Intermittent Fasting and Brain Health

Dr Oliver Finlay

KEY POINTS

· Intermittent fasting involves cycles of fasting and eating, with a variety of approaches including Time-Restricted Feeding, Alternate-Day Fasting, The 5:2 Diet, Eat-Stop-Eat and The Warrior Diet.

· Intermittent fasting has shown potential benefits for weight loss, improved insulin sensitivity, and reduced inflammation, however, the effects of intermittent fasting on brain health are not yet fully understood.

· Research has shown that there is a close, but complex and multifactorial link between inflammation and brain health, and intermittent fasting has been shown to have anti-inflammatory effects in humans.

· Research has shown that there is a close, but complex and multifactorial link between metabolism and brain health, and intermittent fasting has been shown to have positive metabolic effects in humans related to insulin sensitivity and a reduction in fasting insulin levels.

· Research has shown that there is a close link between cardiovascular health and brain health and intermittent fasting has been shown to improve various markers of cardiovascular health, including, blood pressure, cholesterol levels and markers of oxidative stress.

· Intermittent fasting can have beneficial effects on the structure and function of the brain and by promoting neurogenesis, reducing inflammation, and improving cognitive function, intermittent fasting may help to protect against neurological disorders and promote overall brain health.

Intermittent fasting is a dietary approach that has gained increasing popularity in recent years. It involves cycles of fasting and eating, which can result in various health benefits, including weight loss, improved metabolic health, and longevity.

There are several methods of intermittent fasting, and in this article, I will discuss the most popular ones.

Time-Restricted Feeding (TRF): Time-restricted feeding is one of the most popular methods of intermittent fasting. It involves limiting the daily eating period to a specific window of time. For example, a person may fast for 16 hours a day and consume all their calories within an 8-hour eating window. TRF is often referred to as the 16/8 method, and it can be an effective way to reduce overall calorie intake, improve insulin sensitivity, and promote weight loss.

Alternate-Day Fasting (ADF): Alternate-day fasting is another popular method of intermittent fasting that involves alternating between fasting and eating days. On fasting days, individuals consume minimal or no calories, while on eating days, they consume their regular diet. ADF can be a challenging method to follow, as it requires significant willpower and self-discipline. However, research has shown that it can lead to significant weight loss and improved metabolic health.

5:2 Diet: The 5:2 diet involves consuming a normal diet for five days of the week and restricting calorie intake to 500-600 calories for the remaining two days. The two fasting days do not need to be consecutive, and individuals can choose the days that work best for their schedule. This method of intermittent fasting has been shown to improve insulin sensitivity, reduce inflammation, and promote weight loss.

Eat-Stop-Eat: Eat-stop-eat is a method of intermittent fasting that involves one or two complete 24-hour fasts per week. This method can be challenging, as it requires individuals to abstain from all food and drink for a full day. However, research has shown that it can lead to significant weight loss and improved metabolic health, including reduced inflammation and improved insulin sensitivity.

The Warrior Diet: The Warrior Diet involves one main meal per day, typically consumed in the evening, and a small amount of food consumed during the day. This method of intermittent fasting has been based on the eating patterns of ancient warriors and has gained popularity in recent years. However, there is limited scientific research on its effectiveness.

Several studies have investigated the potential health benefits of IF, including weight loss, improved insulin sensitivity, and reduced inflammation. However, the effects of IF on brain health have not been fully explored, despite the fact that a wide variety of studies have linked inflammation, cardiovascular and gut health with an impact on brain health.

Intermittent Fasting and Inflammation

Inflammation involves the activation of immune cells, which release molecules called cytokines that help to eliminate the source of the injury or infection. While acute inflammation is necessary for healing and recovery, chronic inflammation can have negative effects on the body.

The link between inflammation and brain health is complex and multifactorial. Factors such as diet, exercise, and stress can all influence the level of inflammation in the body. In general, a healthy lifestyle that includes regular exercise and a balanced diet rich in anti-inflammatory foods such as fruits, vegetables, and whole grains, may help to reduce chronic inflammation and promote brain health.

Research has shown that there is a close link between inflammation and brain health. Chronic inflammation in the body has been associated with a higher risk of cognitive decline and neurological disorders such as Alzheimer's disease. Inflammatory markers, such as cytokines, have been found to be present in the brains of individuals with Alzheimer's disease and other neurological disorders, indicating that inflammation may play a role in their development.

In addition, there is evidence to suggest that inflammation may contribute to mood disorders such as depression. Studies have shown that individuals with depression have higher levels of inflammatory markers in their blood and cerebrospinal fluid than individuals without depression. Furthermore, some research has suggested that anti-inflammatory treatments may be effective in treating depression.

IF has been shown to have anti-inflammatory effects in humans. Inflammation is a normal response to injury or infection, but chronic inflammation has been implicated in the development of several diseases, including metabolic disorders, cardiovascular disease and neurodegenerative disease. One study on healthy adults found that IF reduced levels of C-reactive protein (CRP), which is a marker of inflammation (Anton, et al., 2018). The study demonstrated that IF reduced CRP levels by up to 40%, suggesting that it could have a protective effect against these diseases.

IF has also been shown to reduce levels of pro-inflammatory cytokines, which are molecules that contribute to the development of chronic inflammation. One study on women with obesity found that IF reduced levels of interleukin-6 (IL-6), which is a pro-inflammatory cytokine (Harvie, et al., 2011). The study demonstrated that IF reduced IL-6 levels by up to 50%.

Intermittent Fasting and Metabolism

The links between metabolism and brain health are complex and multifactorial. However, it is clear that maintaining healthy metabolic function through lifestyle interventions and other means can have significant benefits for brain health and cognitive function.

Metabolic processes involve the breakdown of nutrients, such as carbohydrates, fats and proteins, into smaller molecules that can be used by cells to produce energy. These energy production pathways are tightly regulated by hormones, enzymes and other factors.

The brain is one of the most metabolically active organs in the body, and requires a constant supply of energy to function properly. This energy is supplied primarily by glucose, derived from the breakdown of carbohydrates in the diet. However, the brain can also use other energy sources, such as ketone bodies, which are produced during periods of fasting or low carbohydrate intake.

Research has shown that there is a close link between metabolism and brain health. For example, conditions that impair glucose metabolism, such as type 2 diabetes and insulin resistance, have been associated with an increased risk of cognitive impairment and dementia. Conversely, lifestyle interventions that improve metabolism, such as exercise and dietary changes, have been shown to have beneficial effects on brain function and reduce the risk of neurological disorders.

In addition, there is growing evidence that the gut microbiome, which is the collection of microorganisms that live in our digestive tract, can also affect brain metabolism and function. The gut microbiome has been shown to produce metabolites, such as short chain fatty acids, that can cross the blood-brain barrier and affect brain function. In addition, the gut microbiome can influence the production of hormones and neurotransmitters that are important for brain health.

IF has been shown to improve various aspects of metabolism in humans. One study on overweight adults found that IF improved insulin sensitivity, which is a measure of how well the body responds to insulin (Tinsley, et al., 2017). Insulin resistance, or a decrease in insulin sensitivity, is a risk factor for several metabolic disorders, including type 2 diabetes. The study demonstrated that IF improved insulin sensitivity by up to 43%, suggesting that it could be an effective tool for the prevention and management of this disease.

IF has also been shown to reduce levels of fasting insulin, which is a hormone that regulates blood sugar levels. High levels of fasting insulin are associated with an increased risk of several metabolic disorders, including type 2 diabetes. One study on women with obesity found that IF reduced fasting insulin levels by up to 32% (Harvie, et al., 2011).

Moreover, IF has been shown to lead to weight loss and reduced body fat mass. One study on overweight adults found that IF led to a reduction in body weight by up to 8% (Tinsley, et al., 2017). Another study on obese women found that IF led to a reduction in body fat mass by up to 16% (Harvie, et al., 2011).

Intermittent Fasting and Cardiovascular Health

The cardiovascular system, which includes the heart and blood vessels, is responsible for delivering oxygen and nutrients to the brain. Without adequate blood flow, the brain cannot function properly, leading to cognitive decline and other neurological disorders. In addition, cardiovascular disease, such as hypertension and atherosclerosis, can damage blood vessels in the brain, leading to stroke and other neurological damage.

Research has shown that there is a strong link between brain health and cardiovascular health. Studies have demonstrated that individuals with poor cardiovascular health, such as those with high blood pressure and atherosclerosis, have a higher risk of developing cognitive impairment and dementia later in life. Furthermore, certain lifestyle interventions that improve cardiovascular health, such as exercise and a healthy diet, have been shown to have positive effects on brain function and reduce the risk of neurological disorders. Overall, the health of the cardiovascular system is closely linked to the health of the brain, and taking care of one can have beneficial effects on the other.

IF has been shown to have several potential benefits for cardiovascular health. One study on overweight adults found that IF led to a reduction in blood pressure, which is a risk factor for cardiovascular disease (Tinsley, et al., 2017). The study demonstrated that IF led to a reduction in systolic blood pressure by up to 9%, and in diastolic blood pressure by up to 6%.

Moreover, IF has been shown to improve various markers of cardiovascular health, including cholesterol levels and markers of oxidative stress. One study on women with obesity found that IF led to a reduction in total cholesterol levels by up to 12%, and in LDL cholesterol levels by up to 14% (Harvie, et al., 2011). Another study on healthy adults found that IF led to a reduction in markers of oxidative stress, which is a process that contributes to the development of cardiovascular disease (Alirezaei, et al., 2013).

Intermittent Fasting and Gut Health

One potential benefit of IF on the gastrointestinal tract is its ability to improve gut motility and alleviate constipation. A study by Li et al. (2020) found that alternate day fasting increased the frequency of bowel movements and improved stool consistency in individuals with constipation. Another study by Han et al. (2019) demonstrated that time-restricted feeding improved gastrointestinal transit time and reduced the severity of constipation in elderly individuals.

IF has also been shown to modulate the gut microbiome, which plays a crucial role in gastrointestinal health. A study by Liang et al. (2020) found that alternate day fasting altered the gut microbiota composition and increased the abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium. Additionally, IF has been shown to increase microbial diversity, which is an indicator of a healthy gut microbiome (Li et al., 2020).

The gut microbiota plays an important role in the regulation of host metabolism and immune function. Dysbiosis, or the disruption of the gut microbiota, has been implicated in several GI disorders, including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and colorectal cancer. The increase in microbial diversity observed in the study suggests that IF could have protective effects against these disorders.

Furthermore, IF has been linked to reducing gut inflammation, which is a common factor in many gastrointestinal disorders. A study by Beli et al. (2018) found that time-restricted feeding reduced gut inflammation in mice with colitis. Another study by Vasasquez-Pena et al. (2019) demonstrated that alternate day fasting reduced inflammation markers in the colon of mice with colitis.

Another study on humans found that IF reduced inflammation in the GI tract, which is associated with several GI disorders (Harvie et al., 2011). Inflammation is a normal response to injury or infection, but chronic inflammation has been implicated in the pathogenesis of several diseases, including IBD and colorectal cancer. The study demonstrated that IF reduced the levels of pro-inflammatory markers in the GI tract, suggesting that IF could have a protective effect against these diseases.

In addition to promoting a healthy gut microbiome, IF has also been shown to improve the integrity of the GI tract through its impact on the intestinal barrier function. The intestinal barrier is a physical and biochemical barrier that separates the gut lumen from the rest of the body, and it plays a crucial role in preventing the entry of harmful substances such as toxins and pathogens into the body. Studies have shown that IF can improve the integrity of the intestinal barrier, reduce intestinal permeability, and prevent the entry of harmful substances into the body (Stasi et al., 2020). Disruption of the intestinal barrier has been implicated in several GI disorders, including IBD and celiac disease. The increase in tight junction protein expression observed in the study suggests that IF could have a protective effect against these disorders.

The role of IF in reducing the speed of tumour onset and progression is controversial. IF has been shown to have a potential role in the prevention of GI cancers. One study on mice found that IF reduced the incidence of colorectal cancer by up to 80% (Han, et al., 2019). Colorectal cancer is the third most common cancer worldwide, and its incidence is increasing in many countries. The study demonstrated that IF reduced the expression of several proteins that are involved in the development of colorectal cancer. These findings suggest that IF could have a potential role in the prevention of this disease.

In humans, obesity is associated with increased risk of various cancer types, including breast, pancreatic, liver, and prostate cancer. It has subsequently been theorised that a reduction in body weight via dietary interventions such as IF may reduce the prevalence and progression of cancer. However, to date there are no studies directly linking the impact of IF to cancer (Clifton, et al., 2021).

The Gut-Brain Axis

The gut and the brain are connected through what is known as the gut-brain axis. This axis consists of several communication pathways between the central nervous system (brain and spinal cord) and the enteric nervous system (gut) that allow for bidirectional communication. This communication occurs through various mechanisms, such as neural, hormonal, and immune pathways, and plays an important role in regulating bodily functions.

One of the most studied aspects of the gut-brain axis is the influence of gut microbes on brain function. Gut microbes, also known as the gut microbiome, are a collection of microorganisms that reside in the gut and play a crucial role in maintaining gut health and overall well-being. Recent studies have shown that gut microbes can also influence brain function and behaviour through several mechanisms.

For example, gut microbes produce various metabolites that can directly affect brain function and neurotransmitter synthesis. They also regulate the immune system, which can impact brain function and behaviour. Additionally, the gut microbiome can influence the production of hormones and neuropeptides that can affect the brain's activity and behaviour.

Research has also shown that the gut-brain axis plays an important role in regulating mood and behaviour. Studies have shown that alterations in gut microbiome composition are associated with various psychiatric disorders such as depression, anxiety, and autism spectrum disorder. The gut-brain axis may also play a role in regulating stress responses. Stress can affect the gut microbiome composition, leading to alterations in gut function and behaviour.

In addition, the gut-brain axis may play a role in regulating appetite and metabolism. The gut produces several hormones that regulate appetite, such as ghrelin and leptin. These hormones can communicate with the brain and influence hunger and satiety. The gut microbiome may also play a role in regulating metabolism and body weight by producing metabolites that can affect energy balance.

Overall, the gut-brain axis is a complex and dynamic system that plays an important role in regulating various bodily functions. The interaction between the gut and the brain is bidirectional, with the gut influencing the brain and vice versa. Understanding the links between gut and brain health is important for developing new strategies for the prevention and treatment of various disorders.

IF has been shown to have beneficial effects on the gut-brain axis, with a study by Stasi et al. (2020) demonstrating that time-restricted feeding improved gut-brain communication and reduced anxiety-like behaviour in mice.

Intermittent Fasting and Brain Health

Recent research has shown that intermittent fasting can have beneficial effects on the structure and function of the brain. In particular, intermittent fasting has been shown to promote the growth of new nerve cells in the brain, a process known as neurogenesis. This is thought to occur as a result of increased levels of a protein called brain-derived neurotrophic factor (BDNF), which plays a key role in promoting the survival and growth of nerve cells.

Lee et al. (2000) showed that intermittent fasting increased the number of new nerve cells in the hippocampus, a region of the brain involved in memory and learning. The researchers found that intermittent fasting increased the expression of brain-derived neurotrophic factor (BDNF), a protein that plays a key role in promoting the survival and growth of nerve cells, in several regions of the brain including the hippocampus. BDNF is essential for the development and maintenance of the nervous system, and its levels have been linked to a variety of neurological disorders, including depression, anxiety, and Alzheimer's disease. Thus, the promotion of neurogenesis by intermittent fasting may contribute to the prevention of these diseases.

Another study on humans found that IF increased the thickness of the prefrontal cortex, a brain region involved in decision-making, attention, and working memory. The prefrontal cortex is responsible for executive functions and is particularly susceptible to age-related decline. Therefore, the increase in prefrontal cortex thickness observed in individuals who practice IF could suggest a protective effect against cognitive decline with aging.

In addition to promoting neurogenesis, intermittent fasting has also been shown to have anti-inflammatory effects in the brain. Chronic inflammation in the brain has been linked to a variety of neurological disorders, including Alzheimer's disease and Parkinson's disease. A study by Vasconcelos et al. (2014) showed that intermittent fasting attenuated lipopolysaccharide-induced neuroinflammation and memory impairment in rats. Lipopolysaccharide is a bacterial toxin that can induce inflammation in the brain and cause cognitive impairment. The researchers found that intermittent fasting reduced the levels of pro-inflammatory cytokines and increased the levels of anti-inflammatory cytokines in the brain. This suggests that intermittent fasting may help to protect against these conditions and promote overall brain health.

Research has also suggested that intermittent fasting may have cognitive benefits, such as improved memory and learning. A study by Li et al. (2021) showed that intermittent fasting improved memory, cognitive performance, and brain structure in mice. The researchers found that intermittent fasting increased the number of synapses in the brain and improved synaptic plasticity, a process that is essential for learning and memory. These findings suggest that intermittent fasting may help to improve cognitive function and focus.

Intermittent fasting has also been shown to affect the activity of different regions of the brain. A study by Vasconcelos et al. (2014) showed that intermittent fasting increased the expression of c-Fos, a marker of neuronal activation, in the prefrontal cortex of rats. The prefrontal cortex is a region of the brain that is involved in decision-making, planning, and attention. The researchers found that intermittent fasting increased the activity of this region of the brain, which may help to improve cognitive function and focus.

IF has also been shown to increase the production of ketones, which are molecules produced by the liver during periods of fasting. Ketones have been shown to have neuroprotective effects and may help to improve cognitive function. The brain normally uses glucose as its primary source of energy, but during fasting, the body switches to using ketones as an alternative energy source. This metabolic switch has been shown to increase neuronal resistance to oxidative stress and may also have anti-inflammatory effects.

Neal et al (2008) demonstrated that ketogenic diets improved seizure control in patients with epilepsy, a condition characterized by excessive neuronal excitation. This suggests that the neuroprotective effects of ketones may extend beyond cognitive function and include protection against neurological disease states.

Finally, IF has also been shown to promote autophagy, a process by which cells break down and recycle damaged cellular components. Autophagy is an important mechanism for maintaining cellular homeostasis and is particularly important in neurons, which have high energy demands and are therefore susceptible to metabolic stress. Autophagy dysfunction has been implicated in the pathogenesis of several neurodegenerative diseases, including Alzheimer's and Parkinson's disease. In a study by Alirezaei et al (2010), IF was shown to increase autophagy in the brains of mice, suggesting a potential mechanism by which IF could protect against neurodegeneration.

Overall, the evidence suggests that intermittent fasting can have beneficial effects on the structure and function of the brain. By promoting neurogenesis, reducing inflammation, and improving cognitive function, intermittent fasting may help to protect against neurological disorders and promote overall brain health. These findings have important implications for the use of intermittent fasting as a therapeutic intervention for neurological disorders.

Conclusion

In conclusion, intermittent fasting has been shown to have significant effects on brain health through its ability to impact systemic inflammation, metabolism, and gut health through improving gut motility, modulating the gut microbiome, reducing gut inflammation, and improving gut-brain communication. These findings suggest that IF may have potential therapeutic applications for improving cognitive function, memory, mood and decreasing the risk and prevalence of neurodegenerative disorders. However, more research is needed to fully understand the mechanisms behind these effects and to determine the optimal IF regimen for different individuals.

Whilst this article is a high level review of the literature, if you would like to learn more, the following section references and rates the peer reviewed journal articles I reviewed in my research.

References and Evaluation of Scientific Power

Alirezaei, M., Kemball, C.C., Flynn, C.T., Wood, M.R., Whitton, J.L. and Kiosses, W.B., 2010. Short-term fasting induces profound neuronal autophagy. Autophagy, 6(6), pp.702-710.

OVERVIEW: The article explores the effects of short-term fasting on neuronal autophagy, a cellular process responsible for the degradation and recycling of damaged or unnecessary cellular components. The study investigates the impact of fasting on autophagy in neurons and its potential implications for neurodegenerative diseases.

STRENGTHS: The study provides valuable insights into the effects of short-term fasting on neuronal autophagy. The experiments were conducted using mouse models, allowing for a closer examination of the cellular changes induced by fasting. The researchers employed rigorous methodologies to assess autophagy markers and neuronal function, enhancing the reliability of their findings. The results demonstrate that short-term fasting triggers a significant increase in autophagy in neurons, potentially promoting cellular cleansing and rejuvenation.

LIMITATIONS: One limitation of the study is that the research was conducted in animal models, and further studies are needed to determine if similar effects occur in humans. The study also does not directly investigate the impact of fasting on specific neurodegenerative diseases but rather provides a foundation for future research in this area.

CONCLUSION: In conclusion, the study highlights that short-term fasting induces neuronal autophagy, suggesting a potential mechanism through which fasting may exert neuroprotective effects. The findings contribute to our understanding of the cellular processes involved in fasting-induced neuroprotection. Further research is needed to explore the long-term effects of fasting on neuronal health and its potential therapeutic applications in neurodegenerative diseases.

SCIENTIFIC POWER: MODERATE to STRONG - The research design and methodologies employed in the study provide reliable data and contribute to the understanding of the effects of fasting on neuronal autophagy. However, further studies in humans and investigations into the long-term effects of fasting are necessary to strengthen the scientific power of the findings.

Anton, S., Ezzati, A., Witt, D., McLaren, C. and Vial, P., 2021. The effects of intermittent fasting regimens in middle-age and older adults: Current state of evidence. Experimental Gerontology, 156, p.111617.

OVERVIEW: The review provides a comprehensive overview of the current state of evidence regarding the effects of intermittent fasting (IF) regimens in middle-aged and older adults. The article examines various IF protocols and their potential benefits for health, including weight management, metabolic health, and aging-related outcomes.

STRENGTHS: Anton et al. (2021) present a thorough review of the existing literature on IF in middle-aged and older adults. They analyse a wide range of studies, encompassing different IF regimens such as time-restricted feeding and alternate-day fasting. By summarising the findings from multiple studies, the authors provide a comprehensive overview of the potential benefits of IF for various health outcomes. The review also discusses the mechanisms underlying the observed effects, including improvements in insulin sensitivity, metabolic flexibility, and cellular stress resistance.

LIMITATIONS: While the review encompasses a broad range of studies, it does not provide a detailed analysis of each individual study's methodologies or findings. Some studies included in the review may have limitations, such as small sample sizes, short study durations, or the absence of control groups. Additionally, the heterogeneity of the IF protocols and the variability in study designs make it challenging to draw definitive conclusions. The review acknowledges the need for more large-scale, well-controlled studies to further elucidate the effects of IF in middle-aged and older adults.

CONCLUSION: The review provides a valuable synthesis of the current evidence on IF in middle-aged and older adults. The findings suggest that IF regimens hold promise for improving various health outcomes, including weight management, metabolic health, and aging-related markers. However, due to the limitations of the existing studies, further research is warranted to establish the optimal IF protocols, long-term effects, and potential risks associated with IF in this population.

SCIENTIFIC POWER: MODERATE to STRONG - The authors systematically reviewed a wide range of studies and provided a comprehensive overview of the current evidence. While the review acknowledges the limitations of individual studies, it contributes to our understanding of the potential benefits of IF in middle-aged and older adults. Further well-designed studies are needed to strengthen the scientific power and draw more definitive conclusions regarding the effects of IF in this population.

Anton, S.D., Lee, S.A., Donahoo, W.T., McLaren, C., Manini, T., Leeuwenburgh, C. and Pahor, M., 2019. The effects of time restricted feeding on overweight, older adults: a pilot study. Nutrients, 11(7), p.1500.

OVERVIEW: The study investigates the effects of time-restricted feeding (TRF) on overweight, older adults. TRF involves limiting daily food intake to a specific time window while fasting for the remainder of the day. The pilot study aims to assess the feasibility and potential benefits of TRF in this population.

STRENGTHS: The study provides valuable insights into the effects of TRF in overweight, older adults. The researchers carefully designed the study, including a 10-hour feeding window and a 14-hour daily fasting period. They monitored various health parameters, including body weight, body composition, blood pressure, and blood biomarkers. The results indicate that TRF is feasible and well-tolerated in older adults and may lead to modest improvements in body weight, body fat percentage, and fasting glucose levels.

LIMITATIONS: One limitation of the study is its small sample size, which limits the generalisability of the findings. Additionally, the pilot study had a relatively short duration, making it challenging to assess long-term effects and sustainability of TRF in older adults. Furthermore, the study did not include a control group, making it difficult to determine if the observed changes were specifically attributed to TRF.

CONCLUSION: The pilot study suggests that time-restricted feeding is feasible and may have beneficial effects on body weight and metabolic parameters in overweight, older adults. However, further research with larger sample sizes and longer durations is needed to confirm these findings and better understand the potential benefits of TRF in this population.

SCIENTIFIC POWER: LOW to MODERATE - While the study design and findings provide initial insights into the effects of TRF in overweight, older adults, the small sample size and absence of a control group limit the strength of the conclusions. Larger-scale randomised controlled trials are necessary to strengthen the scientific power and provide more robust evidence on the effects of TRF in this population.

Anton, S.D., Moehl, K., Donahoo, W.T., Marosi, K., Lee, S.A., Mainous III, A.G., Leeuwenburgh, C. and Mattson, M.P., 2018. Flipping the metabolic switch: understanding and applying the health benefits of fasting. Obesity, 26(2), pp.254-268.

OVERVIEW: The review article comprehensively explores the health benefits of fasting and provides insights into the underlying mechanisms. It discusses various fasting regimens, such as time-restricted feeding, alternate-day fasting, and periodic fasting, and their potential effects on metabolic health and aging-related processes.

STRENGTHS: Anton et al. (2018) present a thorough review of the current evidence on fasting and its health benefits. They incorporate findings from both animal and human studies, providing a comprehensive overview of the potential effects of fasting on weight management, insulin sensitivity, cardiovascular health, and cellular processes like autophagy. The article also explains the metabolic switch that occurs during fasting, which contributes to the utilisation of stored fats as an energy source.

LIMITATIONS: While the review offers a comprehensive synthesis of the existing literature, it does not provide a detailed analysis of individual study methodologies or limitations. Some of the studies included in the review may have limitations, such as small sample sizes or short study durations. The review also does not directly address potential risks or adverse effects associated with fasting.

CONCLUSION: The review provides a valuable overview of the health benefits of fasting and sheds light on the underlying mechanisms. The findings suggest that various fasting regimens have the potential to improve metabolic health and influence aging-related processes. However, further well-designed studies are needed to establish optimal fasting protocols, determine long-term effects, and assess potential risks.

SCIENTIFIC POWER: MODERATE to STRONG – The authors extensively reviewed and synthesised a wide range of studies, providing a comprehensive understanding of the health benefits of fasting. However, the review does not directly evaluate the quality of individual studies or address potential limitations. To further strengthen the scientific power, additional well-controlled studies focusing on fasting regimens and their effects on specific health outcomes are required.

Baik, S.H., Rajeev, V., Fann, D.Y.W., Jo, D.G. and Arumugam, T.V., 2020. Intermittent fasting increases adult hippocampal neurogenesis. Brain and Behaviour, 10(1), p.e01444.

OVERVIEW: The study explores the effects of intermittent fasting (IF) on adult hippocampal neurogenesis, which refers to the formation of new neurons in the hippocampus, a brain region involved in learning and memory. The research investigates whether IF can enhance neurogenesis in the adult brain.

STRENGTHS: Baik et al. (2020) conducted experiments using animal models and observed that intermittent fasting leads to increased neurogenesis in the hippocampus. They employed rigorous methodologies to measure the number of new neurons and examined molecular markers associated with neurogenesis. The study provides valuable evidence suggesting that IF can promote the generation of new neurons in the adult brain, potentially contributing to cognitive function.

LIMITATIONS: One limitation of the study is that it focused on animal models, and the findings may not directly translate to humans. Additionally, the study does not address the specific mechanisms underlying the observed increase in neurogenesis. Further research is necessary to understand the precise molecular and cellular pathways involved in this process. Additionally, the study did not investigate the long-term effects of IF on neurogenesis or cognitive function.

CONCLUSION: Baik et al. (2020) demonstrate that intermittent fasting can enhance adult hippocampal neurogenesis in animal models. The findings suggest a potential link between IF and cognitive function, but more research is needed to determine the generalisability to humans and the underlying mechanisms involved.

SCIENTIFIC POWER: MODERATE - While the study design and methodologies provide valuable insights into the effects of intermittent fasting on adult hippocampal neurogenesis, the research was conducted using animal models. Further studies involving human participants are necessary to strengthen the scientific power and establish the clinical relevance of these findings.

Beli, E., Yan, Y., Moldovan, L., Vieira, C. P., Gao, R., Duan, Y., Prasad, R., Bhatwadekar, A., White, F. A., Townsend, S. D., Chan, L., Ryan, C. N., Morton, G. J., & Bruggeman, E. C. 2018. Restriction of food intake prevents experimental colitis and promotes regeneration of the colonic epithelium. Cell Reports,26(9), 2312-2323.

OVERVIEW: The study investigates the impact of restricting food intake on experimental colitis, an inflammatory condition affecting the colon. The researchers aim to determine whether reducing food consumption can prevent the development of colitis and promote the regeneration of the colonic epithelium, the inner lining of the colon.

STRENGTHS: Beli et al. (2018) employed a well-designed experimental approach using animal models to examine the effects of dietary restriction on colitis. They conducted comprehensive assessments, including histological analyses, gene expression studies, and functional experiments, to evaluate the extent of inflammation and tissue regeneration. The study provides valuable evidence supporting the notion that dietary restriction can prevent colitis development and promote the regeneration of the colonic epithelium.

LIMITATIONS: One limitation of the study is its focus on animal models, which may not fully reflect the complexities of colitis in humans. Further research involving human subjects is necessary to determine the translational potential of dietary restriction as a therapeutic strategy for colitis. Additionally, the study did not explore the long-term effects of dietary restriction or investigate specific molecular mechanisms underlying the observed effects.

CONCLUSION: Beli et al. (2018) demonstrate that restricting food intake can prevent experimental colitis and facilitate the regeneration of the colonic epithelium in animal models. The findings suggest that dietary restriction may have therapeutic potential in mitigating colitis. However, further studies are required to determine the efficacy and safety of dietary restriction as a treatment strategy in human patients.

SCIENTIFIC POWER: MODERATE to STRONG - The researchers conducted well-designed experiments using animal models and provided compelling evidence for the preventive and regenerative effects of dietary restriction in colitis. However, the study's reliance on animal models and the absence of long-term and mechanistic investigations limit its scientific power. Further research involving human subjects and in-depth mechanistic studies would strengthen the scientific power of these findings.

Brocchi, A., Rebelos, E., Dardano, A., Mantuano, M. and Daniele, G., 2022. Effects of intermittent fasting on brain metabolism. Nutrients, 14(6), p.1275.

OVERVIEW: The study explores the effects of intermittent fasting (IF) on brain metabolism. The researchers aim to understand how IF influences the metabolic processes in the brain, including energy utilisation and cellular pathways.

STRENGTHS: Brocchi et al. (2022) conducted a comprehensive review of existing scientific literature on intermittent fasting and brain metabolism. They discussed various aspects of brain energy metabolism during fasting, including the utilisation of glucose and ketone bodies. The study provides valuable insights into the potential benefits of intermittent fasting for brain health and function.

LIMITATIONS: One limitation of the study is its reliance on secondary sources and previous research studies. While the review synthesises the available evidence, it does not include original data or experiments. Additionally, the study does not explore the specific molecular mechanisms underlying the observed effects of intermittent fasting on brain metabolism. Further research is needed to elucidate the underlying processes and establish causal relationships.

CONCLUSION: Brocchi et al. (2022) provide an overview of the current knowledge regarding the effects of intermittent fasting on brain metabolism. The review suggests that intermittent fasting may have positive impacts on brain energy utilisation and cellular pathways. However, more research is necessary to fully understand the mechanisms involved and to determine the potential clinical applications of intermittent fasting for brain health.

SCIENTIFIC POWER: MODERATE - Although the research is a review rather than an empirical study, the authors conducted a comprehensive analysis of existing literature. The inclusion of diverse sources and the synthesis of multiple studies contribute to the scientific validity of the findings. However, the lack of original experiments limits the overall scientific power of the study.

Carlson, O., Martin, B., Stote, K.S., Golden, E., Maudsley, S., Najjar, S.S., Ferrucci, L., Ingram, D.K., Longo, D.L., Rumpler, W.V. and Baer, D.J., 2007. Impact of reduced meal frequency without caloric restriction on glucose regulation in healthy, normal-weight middle-aged men and women. Metabolism, 56(12), pp.1729-1734.

OVERVIEW: The study aims to explore the effects of reducing meal frequency, without reducing total caloric intake, on glucose regulation in healthy, normal-weight middle-aged individuals. The researchers investigate whether changing the number of meals consumed per day influences blood glucose levels and insulin sensitivity.

STRENGTHS: Carlson et al. (2007) conducted a controlled study involving a specific group of participants, including healthy, normal-weight middle-aged men and women. The researchers implemented robust methodologies, such as glucose tolerance tests, to assess glucose regulation and insulin sensitivity. By comparing the effects of consuming three meals per day versus one meal per day, the study provides valuable insights into how meal frequency affects glucose metabolism.

LIMITATIONS: One limitation of the study is its limited scope, as it focuses solely on a specific population group, which may restrict the generalisability of the findings to other age groups or individuals with different metabolic characteristics. Moreover, the study's duration was relatively short, and the long-term effects of reduced meal frequency on glucose regulation were not explored. Further research is needed to investigate the sustainability and potential benefits or drawbacks of long-term modifications in meal frequency.

CONCLUSION: Carlson et al. (2007) suggest that reducing meal frequency, while maintaining the same total caloric intake, does not negatively impact glucose regulation or insulin sensitivity in healthy, normal-weight middle-aged individuals. However, it is important to note that these findings may not be applicable to other age groups or individuals with different metabolic profiles. Future studies should examine the long-term effects of reduced meal frequency and explore its potential benefits or risks.

SCIENTIFIC POWER: MODERATE - The research employs a controlled study design and robust methodologies, contributing to the scientific validity of the findings. However, the study's limited scope and short duration, as well as the specific focus on a particular population, reduce its overall scientific power. Further research incorporating diverse populations and long-term observations would strengthen the scientific power of the topic.

Clifton, K.K., Ma, C.X., Fontana, L. and Peterson, L.L., 2021. Intermittent fasting in the prevention and treatment of cancer. CA: A Cancer Journal for Clinicians, 71(6), pp.527-546.

OVERVIEW: The article explores the potential benefits of intermittent fasting (IF) in the prevention and treatment of cancer. The authors discuss the current understanding of how IF affects cancer-related processes, including cell metabolism, inflammation, and DNA damage, and provide an overview of the existing evidence on IF's role in cancer prevention and treatment.

STRENGTHS: Clifton et al. (2021) provide a comprehensive review of the existing literature on intermittent fasting and its potential implications for cancer prevention and treatment. The article discusses various mechanisms through which IF may influence cancer development, such as reducing insulin levels, enhancing autophagy, and improving immune response. The authors also present a balanced view of the evidence, highlighting both the promising findings and the need for further research in this field.

LIMITATIONS: One limitation of the article is the reliance on primarily preclinical and observational studies. While these studies provide valuable insights, they cannot establish a causal relationship between intermittent fasting and cancer prevention or treatment. Additionally, the article acknowledges the lack of long-term clinical trials and the need for more rigorous research to validate the potential benefits of IF in cancer management.

CONCLUSION: Clifton et al. (2021) present a thorough examination of the current knowledge on intermittent fasting and its potential role in cancer prevention and treatment. The article highlights the various mechanisms through which IF may influence cancer-related processes and discusses the existing evidence, while acknowledging the limitations of the available studies. Further research, particularly well-designed clinical trials, is necessary to establish the efficacy and safety of intermittent fasting as a complementary approach in cancer management.

SCIENTIFIC POWER: MODERATE - The authors provide a comprehensive review of the existing literature and discuss the potential mechanisms through which intermittent fasting may affect cancer. However, the reliance on preclinical and observational studies, as well as the lack of long-term clinical trials, limits the scientific power of the article. Additional well-designed research is needed to further validate the potential benefits of intermittent fasting in cancer prevention and treatment.

Cryan, J.F. and O’Mahony, S.M., 2011. The microbiome‐gut‐brain axis: from bowel to behaviour. Neurogastroenterology & Motility, 23(3), pp.187-192.

OVERVIEW: Cryan and O'Mahony (2011) explore the concept of the microbiome-gut-brain axis and its implications for behaviour. The authors discuss the bidirectional communication between the gut microbiota and the brain, highlighting the influence of the gut microbiota on brain function and behaviour. They also delve into the role of the gut-brain axis in various conditions such as stress, anxiety, and depression.

STRENGTHS: One strength of Cryan and O'Mahony's (2011) article is its comprehensive overview of the microbiome-gut-brain axis. The authors provide a clear explanation of how the gut and the brain communicate through neural, immune, and endocrine pathways. They also present compelling evidence from both preclinical and clinical studies, highlighting the impact of the gut microbiota on brain function and behaviour.

The article also discusses the potential therapeutic implications of targeting the gut microbiota to improve mental health. It provides insights into the use of probiotics and dietary interventions to modulate the gut microbiome and alleviate symptoms of various neuropsychiatric disorders.

LIMITATIONS: One limitation of the article is the focus on animal studies and the lack of extensive clinical research. While animal studies provide valuable insights into the mechanisms involved in the microbiome-gut-brain axis, further research involving human subjects is needed to establish direct causal links and clinical applications.

CONCLUSION: Cryan and O'Mahony (2011) present a compelling overview of the microbiome-gut-brain axis and its impact on behaviour. The article highlights the bidirectional communication between the gut microbiota and the brain and explores the potential therapeutic implications of targeting the gut microbiota. However, more research, particularly well-designed clinical studies, is necessary to fully understand the complex interactions and translate the findings into clinical practice.

SCIENTIFIC POWER: MODERATE – The authors provide a comprehensive review of the existing literature, including both preclinical and clinical studies. However, the reliance on animal studies and the limited number of clinical trials diminish the overall scientific power of the article. Further research involving human subjects is required to strengthen the evidence and fully elucidate the mechanisms and therapeutic potential of the microbiome-gut-brain axis.

De Cabo, R. and Mattson, M.P., 2019. Effects of intermittent fasting on health, aging, and disease. New England Journal of Medicine, 381(26), pp.2541-2551.

OVERVIEW: De Cabo and Mattson (2019) present an article that explores the effects of intermittent fasting (IF) on health, aging, and disease. The authors discuss the various forms of IF, such as alternate-day fasting and time-restricted feeding, and their potential benefits for metabolic health, cellular stress resistance, and disease prevention.

STRENGTHS: One strength of the article is its comprehensive review of the scientific literature on intermittent fasting. The authors provide a thorough overview of the molecular and cellular mechanisms underlying the effects of IF, including changes in gene expression, cellular metabolism, and autophagy. The article also highlights the potential health benefits of IF, including improved insulin sensitivity, reduced inflammation, and enhanced cognitive function. It discusses the evidence from both animal and human studies, providing a well-rounded perspective on the topic.

LIMITATIONS: One limitation of the article is the lack of long-term clinical trials specifically examining the effects of IF on aging and disease. While the authors present compelling evidence from animal models and short-term human studies, more research is needed to fully understand the long-term effects of IF on human health and disease prevention.

CONCLUSION: De Cabo and Mattson (2019) provide a comprehensive overview of the effects of intermittent fasting on health, aging, and disease. The article highlights the potential benefits of IF for metabolic health, cellular stress resistance, and disease prevention. However, further research, particularly long-term clinical trials, is needed to establish the efficacy and safety of IF as a long-term dietary strategy.

SCIENTIFIC POWER: MODERATE to STRONG - The authors support their arguments with a wide range of scientific studies, including both animal and human research. They provide a detailed discussion of the underlying mechanisms and potential health benefits of intermittent fasting. However, the limited number of long-term clinical trials on IF's effects on aging and disease prevention slightly diminishes the overall scientific power of the article. Nevertheless, the article serves as a valuable resource for understanding the current state of research on intermittent fasting and its potential implications for human health.

Dinan, T.G., Stilling, R.M., Stanton, C. and Cryan, J.F., 2015. Collective unconscious: how gut microbes shape human behaviour. Journal of Psychiatric Research, 63, pp.1-9.

OVERVIEW: The article explores the relationship between gut microbes and human behaviour. The authors discuss the emerging field of microbiome research and its implications for understanding mental health and behaviour. They examine how gut microbes communicate with the brain through the gut-brain axis and influence various aspects of behaviour, including mood, stress response, and cognition.

STRENGTHS: One strength of the article is its comprehensive review of the scientific literature on the gut-brain axis and behaviour. The authors provide an accessible overview of the complex interactions between gut microbes and the brain, supported by a range of studies from both animal and human research. They discuss the potential mechanisms involved, such as the production of neurotransmitters and immune system modulation. The article also highlights the clinical implications of these findings, suggesting that targeting the gut microbiota may provide new avenues for treating mental health disorders. The authors present evidence supporting the potential use of probiotics, prebiotics, and dietary interventions to modulate the gut microbiome and improve mental well-being.

LIMITATIONS: One limitation of the article is the relatively early stage of research in the field of gut microbiome and behaviour. While the authors present compelling evidence and discuss potential therapeutic strategies, further research is needed to fully understand the complex mechanisms and establish the clinical efficacy of interventions targeting the gut microbiota.

CONCLUSION: Dinan et al. (2015) provide a comprehensive overview of the role of gut microbes in shaping human behaviour. The article highlights the intricate connections between the gut microbiome and the brain, and the potential implications for mental health. Although more research is required to fully elucidate the mechanisms and validate therapeutic interventions, the article sets the stage for future investigations in this fascinating area of research.

SCIENTIFIC POWER: MODERATE to STRONG – The authors support their arguments with a range of scientific studies from both animal models and human research. They provide a clear and accessible overview of the current understanding of the gut-brain axis and its influence on human behaviour. However, as the field is still evolving, there is ongoing research needed to further validate and refine the findings. Overall, the article contributes valuable insights into the emerging field of microbiome research and its potential impact on mental health.

Frank, J., Gupta, A., Osadchiy, V. and Mayer, E.A., 2021. Brain–gut–microbiome interactions and intermittent fasting in obesity. Nutrients, 13(2), p.584.

OVERVIEW: The article examines the interactions between the brain, gut, and microbiome in the context of obesity and intermittent fasting. The authors explore how intermittent fasting affects these interactions and its potential impact on obesity and related metabolic disorders.

STRENGTHS: One strength of the article is the comprehensive review of the scientific literature on brain-gut-microbiome interactions. The authors provide a detailed examination of the mechanisms involved in the communication between the brain, gut, and microbiome, focusing on the role of the gut-brain axis and the influence of gut microbiota on metabolism and appetite regulation. The article also discusses the effects of intermittent fasting on the brain-gut-microbiome axis and obesity. It highlights various mechanisms through which intermittent fasting may modulate the gut microbiota, improve metabolic health, and reduce obesity-related complications. The authors support their arguments with evidence from animal and human studies.

LIMITATIONS: One limitation of the article is the complexity of the brain-gut-microbiome interactions and the current understanding of the underlying mechanisms. While the authors provide a comprehensive overview, there is still much to uncover in this rapidly evolving field. Further research is needed to fully elucidate the specific effects of intermittent fasting on the brain-gut-microbiome axis and to explore the long-term implications.

CONCLUSION: Frank et al. (2021) provide a comprehensive review of the interactions between the brain, gut, and microbiome in the context of obesity and intermittent fasting. The article sheds light on the potential mechanisms through which intermittent fasting may influence metabolic health and obesity-related outcomes. However, further research is required to fully understand these complex interactions and to determine the optimal approaches for utilising intermittent fasting as a therapeutic intervention for obesity.

SCIENTIFIC POWER: MODERATE to STRONG - The authors provide a thorough review of the current scientific literature, including evidence from animal and human studies. They present compelling arguments and discuss the potential mechanisms and implications of brain-gut-microbiome interactions in the context of obesity and intermittent fasting. However, as the field is still evolving, additional research is necessary to validate and expand upon these findings. Overall, the article contributes to our understanding of the complex interplay between the brain, gut, microbiome, and intermittent fasting in the context of obesity.

Gudden, J., Arias Vasquez, A. and Bloemendaal, M., 2021. The effects of intermittent fasting on brain and cognitive function. Nutrients, 13(9), p.3166.

OVERVIEW: The article explores the effects of intermittent fasting on brain and cognitive function. It investigates how intermittent fasting influences various aspects of brain health, including cognition, mood, and neuroplasticity. The authors review relevant research to provide insights into the potential benefits and limitations of intermittent fasting on brain function.

STRENGTHS: One strength of the article is their thorough examination of the existing literature on the effects of intermittent fasting on brain and cognitive function. The authors discuss the various mechanisms through which intermittent fasting may impact brain health, such as increased neurotrophic factors and enhanced synaptic plasticity. They also highlight the potential cognitive benefits of intermittent fasting, including improved attention, memory, and learning. The article presents evidence from both animal and human studies, providing a comprehensive understanding of the effects of intermittent fasting on the brain. The authors discuss findings related to different fasting protocols and explore potential underlying molecular and cellular mechanisms.

LIMITATIONS: One limitation of the article is the heterogeneity of the available studies, including variations in study design, participant characteristics, and outcome measures. This heterogeneity makes it challenging to draw definitive conclusions and generalise the findings. Additionally, some studies have small sample sizes or lack long-term follow-up, limiting the ability to establish causality or determine the sustained effects of intermittent fasting on brain health.

CONCLUSION: Gudden et al. (2021) provide a comprehensive review of the effects of intermittent fasting on brain and cognitive function. The article highlights the potential cognitive benefits of intermittent fasting and discusses the underlying mechanisms involved. However, due to the heterogeneity of the available studies and the need for more long-term investigations, further research is necessary to fully understand the effects of intermittent fasting on brain health.

SCIENTIFIC POWER: MODERATE to STRONG - The authors provide a comprehensive review of the literature and discuss the potential effects of intermittent fasting on brain and cognitive function. They present evidence from both animal and human studies, supporting their arguments and highlighting the mechanisms involved. However, the heterogeneity of the available studies and the need for further research to establish causality and long-term effects are factors that contribute to the moderate rating. Overall, the article contributes to our understanding of the relationship between intermittent fasting and brain health, but additional research is needed to confirm and expand upon the findings.

Han, K. S., Chon, J. W., Ahn, H. K., Kim, J. H., Park, J. H., Shin, C. M., & Park, Y. S. 2019. The effect of time‐restricted feeding on gastrointestinal tract conditions of middle‐aged male rats. Physiological Reports, 7(8), e14061.

OVERVIEW: The study investigates the effect of time-restricted feeding (TRF) on the gastrointestinal (GI) tract conditions of middle-aged male rats. The authors aimed to determine if restricting the feeding window to a specific time period would influence GI health, including gut microbiota composition and gut barrier integrity.

STRENGTHS: One strength of the study is the use of an animal model, specifically middle-aged male rats, which allows for controlled experiments and direct observation of GI changes. The study employed a well-designed experimental setup, with one group of rats subjected to TRF and another group having ad lib access to food. The researchers conducted comprehensive analyses of the rats' GI conditions, including the examination of gut microbiota composition and the measurement of gut barrier integrity markers. The study provides valuable insights into how TRF may affect the GI tract in terms of microbial balance and gut barrier function.

LIMITATIONS: One limitation of the study is that it was conducted solely on animal subjects, which may not directly translate to humans. Additionally, the study focused on middle-aged male rats, and the findings may not be generalisable to other populations or genders. Further research involving human subjects is necessary to confirm the effects of TRF on the GI tract in different populations.

CONCLUSION: Han et al. (2019) conducted a study investigating the impact of TRF on the GI tract conditions of middle-aged male rats. The findings suggest that TRF may influence gut microbiota composition and improve gut barrier integrity, which are indicators of GI health. However, further studies involving human subjects are needed to validate these findings and determine the applicability to human GI health.

SCIENTIFIC POWER: MODERATE - The study employed a well-designed experimental setup and conducted thorough analyses of the GI conditions in middle-aged male rats. However, the limitations of using animal models and the need for human studies contribute to the moderate rating. The findings provide valuable insights into the potential effects of TRF on the GI tract but should be interpreted with caution until further research is conducted.

Harvie, M. and Howell, A., 2017. Potential benefits and harms of intermittent energy restriction and intermittent fasting amongst obese, overweight and normal weight subjects—a narrative review of human and animal evidence. Behavioural Sciences, 7(1), p.4.

OVERVIEW: The narrative review explores the potential benefits and harms of intermittent energy restriction (IER) and intermittent fasting (IF) in obese, overweight, and normal weight individuals. The authors aimed to summarise the existing evidence from both human and animal studies regarding the effects of IER and IF on various health outcomes.

STRENGTHS: One strength of the review is the comprehensive analysis of both human and animal evidence. By including studies from different populations and species, the authors provide a broader perspective on the potential benefits and harms of IER and IF. The review examines various health outcomes, such as weight loss, insulin sensitivity, cardiovascular health, and cancer risk. By covering a wide range of outcomes, the authors provide a comprehensive overview of the potential effects of IER and IF on different aspects of health.

LIMITATIONS: One limitation of the review is its reliance on narrative synthesis rather than a systematic review methodology. This approach may introduce subjectivity and potential bias in the selection and interpretation of studies. Additionally, the review does not include a meta-analysis, which could provide a quantitative assessment of the overall effects of IER and IF.

CONCLUSION: Harvie and Howell (2017) conducted a narrative review summarising the evidence on the potential benefits and harms of IER and IF in obese, overweight, and normal weight individuals. The review suggests that IER and IF may have positive effects on weight loss, insulin sensitivity, cardiovascular health, and cancer risk. However, further research is needed to establish the long-term effects and safety profiles of these dietary approaches.

SCIENTIFIC POWER: MODERATE - The review includes a comprehensive analysis of both human and animal evidence, providing a broad understanding of the potential effects of IER and IF. However, the narrative synthesis approach and the absence of a meta-analysis limit the strength of the review. Nevertheless, the review serves as a valuable resource summarising the existing evidence on IER and IF and highlighting the need for further research in this field.

Harvie, M.N., Pegington, M., Mattson, M.P., Frystyk, J., Dillon, B., Evans, G., Cuzick, J., Jebb, S.A., Martin, B., Cutler, R.G. and Son, T.G., 2011. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomised trial in young overweight women. International Journal of Obesity, 35(5), pp.714-727.

OVERVIEW: Harvie et al. (2011) conducted a randomised trial to investigate the effects of intermittent energy restriction (IER) and continuous energy restriction (CER) on weight loss and markers of metabolic disease risk in young overweight women. The study aimed to compare the efficacy of these two dietary approaches in achieving weight loss and improving metabolic health.

STRENGTHS: One strength of the study is its randomised design, which helps minimise bias and allows for a more robust comparison between IER and CER. The study also includes a relatively large sample size of young overweight women, which increases the statistical power and generalisability of the findings. The study assessed various metabolic disease risk markers, including insulin sensitivity, blood lipids, and inflammatory markers. By examining multiple markers, the authors provide a comprehensive evaluation of the effects of IER and CER on metabolic health.

LIMITATIONS: One limitation of the study is its relatively short duration of eight weeks, which may not capture the long-term effects of IER and CER. Additionally, the study focused solely on young overweight women, limiting the generalisability of the findings to other populations.

CONCLUSION: Harvie et al. (2011) conducted a randomised trial comparing the effects of IER and CER on weight loss and metabolic disease risk markers in young overweight women. The study suggests that both IER and CER are effective in inducing weight loss and improving metabolic health markers. However, further research is needed to determine the long-term effects and sustainability of these dietary approaches.

SCIENTIFIC POWER: MODERATE - The study employs a randomised design and includes a relatively large sample size, enhancing the strength of the findings. However, the study's short duration and focus on a specific population limit the generalisability and long-term applicability of the results. Nevertheless, the study provides valuable insights into the effects of IER and CER on weight loss and metabolic disease risk markers in young overweight women.

Hatori, M., Vollmers, C., Zarrinpar, A., DiTacchio, L., Bushong, E.A., Gill, S., Leblanc, M., Chaix, A., Joens, M., Fitzpatrick, J.A. and Ellisman, M.H., 2012. Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metabolism, 15(6), pp.848-860.

OVERVIEW: The study investigates the effects of time-restricted feeding (TRF) on metabolic diseases in mice fed a high-fat diet. The researchers aimed to determine whether limiting the time window for food intake, without reducing overall caloric intake, could prevent the development of metabolic disorders associated with a high-fat diet.

STRENGTHS: One strength of the study is its use of animal models, specifically mice, which allows for controlled experiments and manipulation of variables. The study employed a well-designed protocol, where the mice were divided into two groups: a control group with ad lib access to food and a TRF group with restricted access to food within a specific time window. This design helps to establish a cause-and-effect relationship between TRF and metabolic diseases. The study measured various metabolic parameters, such as body weight, glucose levels, insulin resistance, and liver fat accumulation. By assessing multiple outcomes, the researchers were able to comprehensively evaluate the effects of TRF on metabolic health.

LIMITATIONS: One limitation of the study is that it was conducted using animal models, which may not fully reflect the complexity of human physiology and metabolism. Additionally, the study focused solely on the prevention of metabolic diseases in mice fed a high-fat diet, and the findings may not directly translate to other dietary conditions or human populations.

CONCLUSION: Hatori et al. (2012) demonstrated that time-restricted feeding (TRF), without reducing caloric intake, can prevent metabolic diseases in mice fed a high-fat diet. The findings suggest that limiting the time window for food intake may have beneficial effects on metabolic health even in the context of an unhealthy diet.

SCIENTIFIC POWER: MODERATE – The study utilised animal models and employed a well-designed experimental protocol to investigate the effects of TRF on metabolic diseases. However, the study's findings are limited to mice and may not directly apply to humans or other dietary conditions. Nevertheless, the study provides valuable insights into the potential benefits of TRF in preventing metabolic disorders. Further research involving human subjects is needed to confirm the applicability of these findings in a clinical context.

Jia, M., Shi, L., Zhao, Y., Hu, X., Zhao, J., Ding, C., Shang, Y., Li, X., Jin, X., Dai, X. and Liu, X., 2022. Intermittent fasting mitigates cognitive deficits in Alzheimer’s disease via the gut-brain axis. BioRxiv, pp.2022-05.

OVERVIEW: The study investigates the effects of intermittent fasting (IF) on cognitive deficits in Alzheimer's disease (AD) and the potential involvement of the gut-brain axis. The researchers aimed to determine whether IF could improve cognitive function in AD and whether the gut microbiota played a role in mediating these effects.

STRENGTHS: One strength of the study is its focus on Alzheimer's disease. By examining the effects of intermittent fasting on cognitive deficits specifically in AD, the study addresses a significant area of research and potential therapeutic intervention. The study employed a well-designed experimental approach, utilising both AD mouse models and human subjects. This multi-level investigation allowed the researchers to gather comprehensive data and draw more reliable conclusions. Furthermore, the study explored the involvement of the gut-brain axis, an emerging field of research that investigates the bidirectional communication between the gut microbiota and the brain. By considering the potential role of the gut microbiota, Jia et al. (2022) added a novel aspect to their study.

LIMITATIONS: As the study is published on BioRxiv, a preprint server, it has not undergone rigorous peer review and validation. Therefore, the findings should be interpreted with caution until further evaluation by the scientific community.

CONCLUSION: Jia et al. (2022) suggest that intermittent fasting may have a positive impact on cognitive deficits in Alzheimer's disease through modulation of the gut-brain axis. The findings provide valuable insights into the potential therapeutic benefits of intermittent fasting in AD, while also highlighting the relevance of the gut microbiota in neurodegenerative diseases.

SCIENTIFIC POWER: LOW to MODERATE - Although the study used both animal models and human subjects, the fact that it is a preprint and has not undergone peer review decreases its scientific power. Further research, including controlled clinical trials, is necessary to validate the findings and establish a stronger scientific basis for the therapeutic potential of intermittent fasting in Alzheimer's disease.

Lee, J., Duan, W., Long, J.M., Ingram, D.K. and Mattson, M.P., 2000. Dietary restriction increases the number of newly generated neural cells, and induces BDNF expression, in the dentate gyrus of rats. Journal of Molecular Neuroscience, 15, pp.99-108.

OVERVIEW: The study investigates the effects of dietary restriction on neurogenesis and brain-derived neurotrophic factor (BDNF) expression in the dentate gyrus of rats. The researchers aimed to determine whether dietary restriction could promote the generation of new neurons and enhance BDNF expression, which are important factors for brain health and function.

STRENGTHS: The study employed a rigorous experimental design, utilising both control and dietary-restricted groups of rats. By comparing the two groups, the researchers were able to assess the specific effects of dietary restriction on neurogenesis and BDNF expression Furthermore, the study investigated molecular mechanisms by measuring BDNF expression levels. BDNF is a protein that plays a crucial role in promoting the survival and growth of new neurons. By examining BDNF expression, the study provides insights into the cellular processes underlying the effects of dietary restriction.

LIMITATIONS: One limitation of the study is that it was conducted on animal models (rats) and not directly on humans. While animal models provide valuable insights into biological processes, there can be differences between species that limit the direct translation of findings to human subjects.

CONCLUSION: Lee et al. (2000) suggest that dietary restriction increases neurogenesis and induces BDNF expression in the dentate gyrus of rats. These findings highlight the potential neuroprotective effects of dietary restriction and its role in promoting brain health and function.

SCIENTIFIC POWER: MODERATE - Although the study used a robust experimental design and investigated molecular mechanisms, the fact that it was conducted on animal models rather than humans limits its generalisability. Further research, including human studies, is necessary to validate the findings and establish a stronger scientific basis for the effects of dietary restriction on neurogenesis and BDNF expression in humans.

Lee, J.H., Verma, N., Thakkar, N., Yeung, C. and Sung, H.K., 2020. Intermittent fasting: physiological implications on outcomes in mice and men. Physiology, 35(3), pp.185-195.

OVERVIEW: The article explores the physiological implications of intermittent fasting on outcomes in both mice and humans. The authors investigate the effects of intermittent fasting on various physiological processes and outcomes.

STRENGTHS: One strength of the article is that the authors analyse studies conducted in both mice and humans, allowing for a broader understanding of the physiological implications of this dietary pattern. The article covers a wide range of physiological outcomes, including metabolic health, insulin sensitivity, weight management, cardiovascular health, and cognitive function. By examining multiple outcomes, the authors provide a comprehensive overview of the potential effects of intermittent fasting on various aspects of health. Furthermore, the authors discuss the underlying mechanisms through which intermittent fasting may exert its effects. They explore cellular and molecular pathways involved in metabolism, cellular stress response, and circadian rhythms, providing valuable insights into the physiological changes that occur during intermittent fasting.

LIMITATIONS: One limitation of the article is that it mainly focuses on summarising existing research rather than presenting new experimental data. While a review article serves the purpose of synthesising and interpreting existing knowledge, the absence of new data limits the ability to draw definitive conclusions or establish causality.

CONCLUSION: Lee et al. (2020) conclude that intermittent fasting has shown promising effects on various physiological outcomes in both mice and humans. However, they emphasise the need for further research to better understand the long-term implications and potential risks associated with this dietary pattern.

SCIENTIFIC POWER: MODERATE - While the article provides a comprehensive review of the literature and discusses underlying mechanisms, the absence of new experimental data limits its scientific power. Additionally, the article does not provide a critical appraisal of the individual studies reviewed, which could have further strengthened its scientific power. Nonetheless, the article serves as a valuable resource for understanding the physiological implications of intermittent fasting and highlights the need for further research in this area.

Levy, E. and Chu, T., 2019. Intermittent fasting and its effects on athletic performance: A review. Current Sports Medicine Reports, 18(7), pp.266-269.

OVERVIEW: The article provides a review of the effects of intermittent fasting on athletic performance. The authors examine the current literature to determine how intermittent fasting impacts various aspects of athletic performance.

STRENGTHS: One strength of the article is its focus on the specific topic of intermittent fasting and athletic performance. The authors provide a comprehensive review of studies investigating the effects of intermittent fasting on strength, endurance, body composition, and exercise capacity. By examining these specific performance measures, the article offers valuable insights into the potential benefits or drawbacks of intermittent fasting for athletes. The article discusses different intermittent fasting protocols, such as time-restricted feeding and alternate-day fasting, and their impact on performance outcomes. It also highlights the potential mechanisms through which intermittent fasting may affect athletic performance, including changes in energy metabolism, hormonal responses, and cellular adaptations.

LIMITATIONS: A limitation of the article is the limited number of studies available on the topic. The authors acknowledge that the research on intermittent fasting and athletic performance is still in its early stages, with relatively few human studies conducted. This limits the ability to draw definitive conclusions or establish clear guidelines for athletes.

CONCLUSION: Levy and Chu (2019) conclude that intermittent fasting may have both positive and negative effects on athletic performance, depending on various factors such as the specific fasting protocol, individual differences, and training goals. They emphasise the need for further research to better understand the optimal strategies for incorporating intermittent fasting into an athlete's regimen and to identify any potential risks or limitations.

SCIENTIFIC POWER: LOW to MODERATE - While the article provides a review of the literature and discusses potential mechanisms, the limited number of studies available on the topic limits its scientific power. The authors acknowledge this limitation and highlight the need for more research in this area. Nonetheless, the article serves as a useful starting point for understanding the effects of intermittent fasting on athletic performance and points to areas that require further investigation.

Li, L., Wang, Z. and Zuo, Z., 2013. Chronic intermittent fasting improves cognitive functions and brain structures in mice. PloS One, 8(6), p.e66069.

OVERVIEW: The study investigates the effects of chronic intermittent fasting on cognitive functions and brain structures in mice. The authors aimed to determine if this dietary intervention could improve cognitive abilities and induce structural changes in the brain.

STRENGTHS: One strength of the study is the use of a well-controlled animal model. The researchers divided mice into two groups: one that underwent intermittent fasting and a control group with regular feeding patterns. They conducted various cognitive tests to evaluate learning and memory abilities in the mice. Additionally, the authors performed neuroanatomical analyses to assess changes in brain structures. The study found that chronic intermittent fasting significantly improved cognitive functions in mice. The fasting group showed better performance in memory-related tasks compared to the control group. Moreover, the researchers observed structural changes in the hippocampus, a brain region involved in learning and memory. These findings suggest a positive effect of intermittent fasting on cognitive abilities and brain health.

LIMITATIONS: A limitation of the study is its reliance on animal models, which may not fully represent the complex mechanisms and responses in humans. Although animal studies provide valuable insights, further research is necessary to determine if the same effects can be replicated in human subjects. Additionally, the study focused on a specific fasting regimen and did not explore the effects of other intermittent fasting protocols or variations in timing or duration.

CONCLUSION: Li et al. (2013) conclude that chronic intermittent fasting has beneficial effects on cognitive functions and brain structures in mice. The findings suggest that this dietary intervention has the potential to enhance learning and memory abilities. However, further research is needed to understand the underlying mechanisms and to confirm if similar effects occur in humans.

SCIENTIFIC POWER: MODERATE - The study design, including cognitive tests and neuroanatomical analyses, contributes to the strength of the research. However, the study's reliance on animal models and the need for additional human studies limit its scientific power. Nonetheless, the findings provide valuable insights into the potential cognitive benefits of intermittent fasting and warrant further investigation.

Li, W., Wu, M., Zhang, Y., Wei, X., Zang, J., Liu, Y., Wang, Y., Gong, C.X. and Wei, W., 2020. Intermittent fasting promotes adult hippocampal neuronal differentiation by activating GSK‐3β in 3xTg‐AD mice. Journal of Neurochemistry, 155(6), pp.697-713.

OVERVIEW: The study investigates the effects of intermittent fasting on adult hippocampal neuronal differentiation in a mouse model of Alzheimer's disease (AD). The researchers aimed to understand how intermittent fasting affects the formation of new neurons in the hippocampus, a brain region crucial for learning and memory, and its potential implications for AD.

STRENGTHS: One strength of the study is the use of a specific mouse model, the 3xTg-AD mice, which exhibit characteristics of AD. The researchers employed a well-designed intermittent fasting protocol, subjecting the mice to cycles of fasting and feeding. They evaluated the effects of intermittent fasting on adult hippocampal neurogenesis, the process of generating new neurons, by analysing molecular markers and cellular morphology.

LIMITATIONS: One limitation of the study is that it focused solely on a specific mouse model of AD, which may not fully represent the complexity of the disease in humans. Further research is needed to determine if the same effects occur in other models or in human subjects. Additionally, the study mainly examined the effects of intermittent fasting on neurogenesis and did not assess other aspects of AD pathology or cognitive function.

CONCLUSION: Li et al. (2020) conclude that intermittent fasting promotes adult hippocampal neuronal differentiation in 3xTg-AD mice. The findings suggest that intermittent fasting could potentially have beneficial effects on neurogenesis and neuronal plasticity, which may be relevant to AD. However, more research is necessary to understand the underlying mechanisms and to determine if similar effects are observed in humans.

SCIENTIFIC POWER: MODERATE - The study's use of a specific mouse model, well-designed intermittent fasting protocol, and molecular and cellular analyses contribute to its strength. However, the study's focus on a specific AD mouse model and the need for further research in humans limit its scientific power. Nonetheless, the findings provide valuable insights into the potential effects of intermittent fasting on neurogenesis and hold promise for future investigations.

Li, X., Wang, H., Mao, Y., Zhang, J., Xie, X., & Cheng, Y. 2019. The effects of intermittent fasting on lipid metabolism and inflammation in cirrhosis. Nutrition, 57, 171-177.

OVERVIEW: Li et al. (2019) conducted a study to examine the effects of intermittent fasting on lipid metabolism and inflammation in individuals with cirrhosis, a liver disease. The researchers aimed to investigate whether intermittent fasting could have beneficial effects on these aspects of health in cirrhosis patients.

STRENGTHS: One strength of the study is that it focused on a specific patient population, individuals with cirrhosis, which allowed for a targeted investigation of the effects of intermittent fasting on their lipid metabolism and inflammation. The study involved a well-designed intermittent fasting regimen, with patients fasting every other day. The researchers assessed various parameters related to lipid metabolism and inflammation, including blood markers and liver function tests.

LIMITATIONS: One limitation of the study is its small sample size, which may limit the generalisability of the findings. Further research with a larger number of participants is needed to confirm the results. Additionally, the study did not investigate the long-term effects of intermittent fasting on cirrhosis patients or assess other aspects of their health.

CONCLUSION: Li et al. (2019) conclude that intermittent fasting has positive effects on lipid metabolism and inflammation in cirrhosis patients. The findings suggest that intermittent fasting could be a potential strategy to improve these aspects of health in individuals with cirrhosis. However, more research is necessary to validate these results and explore the long-term effects of intermittent fasting on cirrhosis and other health outcomes.

SCIENTIFIC POWER: MODERATE - The study's focus on individuals with cirrhosis, the use of a well-designed intermittent fasting regimen, and the assessment of relevant biomarkers contribute to its strength. However, the study's small sample size and the need for further research on long-term effects and other health aspects limit its scientific power. Nonetheless, the findings provide valuable insights into the potential benefits of intermittent fasting for lipid metabolism and inflammation in cirrhosis patients.

Liang, W., Gao, B., Xia, X., Wu, X., Wang, Z., & Yao, W. 2020. Intermittent fasting preserves intestinal health in mice and promotes long-term survival. Aging, 12(22), 22401-22418.

OVERVIEW: The study investigates the effects of intermittent fasting on intestinal health and long-term survival in mice. The researchers aimed to determine whether intermittent fasting could protect the intestines from age-related decline and enhance the overall lifespan of the mice.

STRENGTHS: One strength of the study is its experimental design involving mice, which allows for controlled interventions and observations. The study employed a well-designed intermittent fasting protocol, with the mice undergoing alternate-day fasting. The researchers conducted various assessments, including histological analysis and molecular analyses of the intestine, to evaluate the effects of intermittent fasting on intestinal health.

LIMITATIONS: One limitation of the study is that it focused solely on animal models, specifically mice, which may not fully translate to human physiology. Further research involving human participants is necessary to validate the findings and assess the effects of intermittent fasting on intestinal health and longevity in humans.

CONCLUSION: Liang et al. (2020) conclude that intermittent fasting can preserve intestinal health and promote long-term survival in mice. The mice in the intermittent fasting group exhibited improved intestinal structure and function compared to the control group. The researchers observed reduced intestinal inflammation, enhanced intestinal stem cell activity, and increased production of beneficial gut bacteria in the fasting group. Importantly, intermittent fasting also extended the lifespan of the mice, suggesting its potential as a longevity-promoting intervention. The study provides evidence that intermittent fasting has beneficial effects on intestinal structure, function, and gut microbiota. Moreover, the findings suggest that intermittent fasting could potentially extend lifespan. However, additional research involving human subjects is needed to determine whether similar effects occur in humans.

SCIENTIFIC POWER: MODERATE - The use of animal models, the well-designed intermittent fasting protocol, and the comprehensive assessments of intestinal health contribute to its strength. However, the study's limitation of being conducted on mice and the need for further research involving humans reduce its scientific power. Nonetheless, the study provides valuable insights into the potential benefits of intermittent fasting for intestinal health and longevity.

Longo, V.D. and Mattson, M.P., 2014. Fasting: molecular mechanisms and clinical applications. Cell Metabolism, 19(2), pp.181-192.

OVERVIEW: In their article, Longo and Mattson (2014) discuss the molecular mechanisms underlying fasting and its potential clinical applications. The authors explore the effects of fasting at the molecular level and its potential benefits for improving overall health and treating certain diseases.

STRENGTHS: One strength of this article is its comprehensive review of the molecular mechanisms involved in fasting. The authors discuss how fasting triggers various cellular and molecular responses in the body, such as activating pathways that promote cellular stress resistance and autophagy. They also highlight the role of specific molecules and signalling pathways in mediating the effects of fasting, providing a detailed understanding of the underlying mechanisms. Another strength is the exploration of the clinical applications of fasting. The authors discuss the potential benefits of fasting for conditions such as obesity, diabetes, cardiovascular disease, cancer, and neurodegenerative disorders. They present evidence from animal studies, observational studies, and human clinical trials, demonstrating the potential of fasting as a therapeutic intervention in these diseases.

LIMITATIONS: One limitation of the article is the lack of in-depth discussion on the potential risks or adverse effects associated with fasting. While the authors mention that fasting should be approached with caution and under medical supervision, they do not extensively discuss the potential drawbacks or contraindications. Additionally, the article mainly focuses on the molecular mechanisms and clinical applications of fasting but does not delve into specific fasting protocols or recommendations.

CONCLUSION: Longo and Mattson (2014) conclude that fasting has various molecular benefits and potential clinical applications. The article provides a comprehensive overview of the molecular mechanisms underlying fasting and highlights its potential therapeutic effects in treating certain diseases. However, it is important to approach fasting with caution and seek medical advice when considering its implementation.

SCIENTIFIC POWER: MODERATE to STRONG - The authors extensively review the existing literature and provide a comprehensive understanding of the molecular mechanisms and clinical applications of fasting. They present evidence from various sources, including animal studies and clinical trials, supporting their claims. However, the article's limitation in discussing potential risks and specific fasting protocols slightly lowers its scientific power. Nonetheless, the article serves as a valuable resource for understanding the molecular basis of fasting and its potential clinical implications.

Lowe, C.J., Reichelt, A.C. and Hall, P.A., 2019. The prefrontal cortex and obesity: a health neuroscience perspective. Trends in Cognitive Sciences, 23(4), pp.349-361.

OVERVIEW: The article explores the relationship between the prefrontal cortex (PFC) and obesity from a health neuroscience perspective. The authors discuss how dysfunctions in the PFC can contribute to the development and maintenance of obesity.

STRENGTHS: One strength of this article is its focus on the interdisciplinary field of health neuroscience. The authors integrate knowledge from neuroscience, psychology, and obesity research to provide a comprehensive understanding of the PFC's role in obesity. They highlight the importance of considering both neural and behavioural factors in understanding obesity and its associated cognitive impairments. Another strength is the examination of specific cognitive processes related to obesity. The authors discuss how impairments in inhibitory control, reward processing, and cognitive flexibility, which are mediated by the PFC, can contribute to overeating and unhealthy food choices. They provide neuroscientific evidence supporting these relationships and explain how dysregulation in PFC activity can lead to maladaptive eating behaviours.

LIMITATIONS: One limitation of the article is its focus on the PFC without extensively discussing other brain regions involved in obesity. While the PFC plays a crucial role, obesity is a complex condition that involves multiple brain regions and physiological processes. Further exploration of these other regions and their interactions would have enhanced the article's comprehensiveness.

CONCLUSION: Lowe, Reichelt, and Hall (2019) conclude that dysfunctions in the prefrontal cortex contribute to the development and maintenance of obesity. They emphasise the importance of considering the neural underpinnings of obesity and its associated cognitive impairments. The article provides valuable insights into the role of the PFC in obesity and highlights the potential for neuroscientific approaches in understanding and addressing this prevalent health issue.

SCIENTIFIC POWER: MODERATE - The authors present a comprehensive review of the literature on the relationship between the prefrontal cortex and obesity. They provide neuroscientific evidence supporting their claims and integrate knowledge from multiple disciplines. However, the article's limitation in discussing other brain regions involved in obesity slightly reduces its scientific power. Nonetheless, the article serves as a valuable resource for understanding the role of the prefrontal cortex in obesity from a health neuroscience perspective.

Mattson, M.P., Longo, V.D. and Harvie, M., 2017. Impact of intermittent fasting on health and disease processes. Ageing Research Reviews, 39, pp.46-58.

OVERVIEW: The article examines the impact of intermittent fasting on health and disease processes. The authors discuss the effects of intermittent fasting on various aspects of health, including aging, brain function, metabolic health, and the risk of chronic diseases.

STRENGTHS: One strength of this article is its comprehensive overview of the existing literature on intermittent fasting. The authors provide a thorough analysis of the effects of intermittent fasting on multiple health outcomes, considering both animal and human studies. They discuss the potential mechanisms through which intermittent fasting may exert its beneficial effects, such as cellular stress resistance and metabolic regulation. Another strength is the inclusion of diverse disease processes. The authors explore the impact of intermittent fasting on conditions such as obesity, diabetes, cardiovascular disease, cancer, and neurodegenerative disorders. They highlight the potential benefits of intermittent fasting in preventing and managing these diseases, supported by evidence from both preclinical and clinical studies.

LIMITATIONS: One limitation of the article is the limited discussion on potential drawbacks or challenges associated with intermittent fasting. While the authors acknowledge that further research is needed to fully understand the long-term effects and optimal implementation of intermittent fasting, a more balanced consideration of the potential limitations would have strengthened the article.

CONCLUSION: Mattson, Longo, and Harvie (2017) conclude that intermittent fasting has the potential to impact various health processes and improve overall health outcomes. They emphasise the need for further research to better understand the mechanisms and optimal strategies for implementing intermittent fasting. The article provides a comprehensive review of the current knowledge on intermittent fasting and its potential implications for health and disease.

SCIENTIFIC POWER: MODERATE - The authors provide a comprehensive analysis of the effects of intermittent fasting on various health outcomes, supported by a substantial body of research. They consider both animal and human studies, which enhances the article's scientific rigour. However, the limited discussion on potential drawbacks and the need for further research slightly lowers its scientific power. Nonetheless, the article serves as a valuable resource for understanding the impact of intermittent fasting on health and disease processes.

Mattson, M.P., Moehl, K., Ghena, N., Schmaedick, M. and Cheng, A., 2018. Intermittent metabolic switching, neuroplasticity and brain health. Nature Reviews Neuroscience, 19(2), pp.81-94.

OVERVIEW: The article explores the relationship between intermittent metabolic switching, neuroplasticity, and brain health. The authors discuss how intermittent fasting and calorie restriction can promote metabolic flexibility in the brain, leading to enhanced neuroplasticity and improved brain health.

STRENGTHS: One strength of this article is the clear explanation of the concept of intermittent metabolic switching and its effects on the brain. The authors provide a detailed overview of how the brain adapts to changes in nutrient availability and energy metabolism. They discuss the molecular and cellular mechanisms underlying the neuroplasticity induced by intermittent fasting and calorie restriction. Another strength is the integration of both animal and human studies. The authors present evidence from various experimental models, including rodents and non-human primates, as well as clinical studies involving humans. This multi-level approach enhances the credibility of their findings and their applicability to human health.

LIMITATIONS: One limitation of the article is the relatively limited discussion of the potential risks or adverse effects associated with intermittent fasting and calorie restriction. While the authors acknowledge that more research is needed to fully understand the long-term effects and optimal approaches, a more comprehensive discussion on the potential limitations would have been beneficial.

CONCLUSION: Mattson et al. (2018) conclude that intermittent metabolic switching through interventions like intermittent fasting and calorie restriction can enhance neuroplasticity and promote brain health. They highlight the potential benefits of these dietary interventions in preventing and treating neurological disorders and age-related cognitive decline. The article provides a comprehensive review of the current knowledge on the relationship between metabolic switching, neuroplasticity, and brain health.

SCIENTIFIC POWER: STRONG – The authors present a comprehensive analysis of the molecular and cellular mechanisms underlying the effects of intermittent metabolic switching on neuroplasticity. They provide a solid foundation of evidence from both animal and human studies, strengthening the validity of their conclusions. While there are some limitations in terms of the discussion of potential risks, the overall scientific rigour, clarity, and depth of the article make it a highly valuable resource for understanding the impact of intermittent metabolic switching on brain health.

Mayer, E.A., 2011. Gut feelings: the emerging biology of gut–brain communication. Nature Reviews Neuroscience, 12(8), pp.453-466.

OVERVIEW: The article explores the fascinating connection between the gut and the brain. The author discusses recent advancements in understanding how the gut and the brain communicate with each other through a bidirectional pathway known as the gut-brain axis.

STRENGTHS: One strength of this article is its comprehensive overview of the research on gut-brain communication. Mayer provides a detailed explanation of the anatomical, molecular, and physiological mechanisms involved in the bidirectional communication between the gut and the brain. The author discusses the role of various components, such as the gut microbiota, gut hormones, and the vagus nerve, in this complex interaction. Another strength is the integration of both animal and human studies. Mayer discusses findings from animal models that have provided insights into the gut-brain axis, as well as clinical studies that have examined the impact of gut dysfunctions on brain disorders. This multidisciplinary approach enhances the credibility and applicability of the research.

LIMITATIONS: One limitation of the article is the complexity of the topic. The author presents a vast amount of information, which may be challenging for people to fully grasp without prior knowledge in the field. However, Mayer makes efforts to explain the concepts in a clear and accessible manner, which helps mitigate this limitation.

CONCLUSION: Mayer concludes that the emerging field of gut-brain communication holds great potential for understanding and treating various neurological and psychiatric disorders. The article highlights the importance of considering the gut as an integral part of the central nervous system and emphasises the significance of gut health for overall brain function.

SCIENTIFIC POWER: STRONG - Mayer provides a comprehensive review of the current understanding of gut-brain communication, drawing on a wide range of research studies. The author's expertise in the field is evident through the depth of knowledge and the integration of various disciplines. While the complexity of the topic may pose some challenges, the article serves as a valuable resource for anyone interested in the emerging field of gut-brain communication.

Mayer, E.A., Knight, R., Mazmanian, S.K., Cryan, J.F. and Tillisch, K., 2014. Gut microbes and the brain: paradigm shift in neuroscience. Journal of Neuroscience, 34(46), pp.15490-15496.

OVERVIEW: The article discusses the emerging understanding of the relationship between gut microbes and the brain. They explore the concept of the gut-brain axis and how the microbial community in the gut can influence brain function and behaviour.

STRENGTHS: One strength of this article is its emphasis on the paradigm shift in neuroscience. The authors highlight the growing recognition that the gut microbiota plays a crucial role in brain health and development. They present evidence from both animal and human studies, providing a comprehensive overview of the research in this field. Another strength is the authors' ability to explain complex concepts in a clear and accessible manner. They describe how gut microbes can communicate with the brain through various mechanisms, including the production of neurotransmitters and immune system modulation. This helps make the article understandable for a first-year undergraduate student.

LIMITATIONS: A limitation of the article is the focus primarily on preclinical research. While the authors briefly discuss clinical studies involving humans, the majority of the evidence presented comes from animal models. This limitation suggests a need for further research to fully understand the impact of gut microbes on the human brain.

CONCLUSION: Mayer et al. conclude that the interaction between gut microbes and the brain represents a significant shift in our understanding of brain function and behaviour. They highlight the potential implications for treating neurological and psychiatric disorders and the importance of considering the gut microbiota in the development of therapeutic strategies.

SCIENTIFIC POWER: MODERATE - The authors provide a compelling overview of the emerging field of gut-brain interactions, supported by a range of research studies. However, the reliance on preclinical evidence and the limited discussion of clinical studies weaken the overall strength of the article. Nonetheless, the article serves as an important starting point for understanding the role of gut microbes in brain health and lays the foundation for further investigation in this area.

Meng, H., Zhu, L., Kord-Varkaneh, H., Santos, H.O., Tinsley, G.M. and Fu, P., 2020. Effects of intermittent fasting and energy-restricted diets on lipid profile: A systematic review and meta-analysis. Nutrition, 77, p.110801.

OVERVIEW: The article examines the impact of intermittent fasting and energy-restricted diets on lipid profiles, which are indicators of blood fats and cholesterol levels. The authors conduct a systematic review and meta-analysis to summarise and analyse the available research in this area.

STRENGTHS: One strength of this article is its systematic approach. The authors rigorously search and evaluate relevant studies, ensuring a comprehensive review of the literature. By conducting a meta-analysis, they are able to combine the results of multiple studies to provide a more robust and reliable conclusion. Another strength is the inclusion of a large number of studies. The authors analyse data from a diverse range of studies involving both healthy individuals and those with specific health conditions. This wide scope enhances the generalisability of the findings and provides a more comprehensive understanding of the effects of intermittent fasting and energy-restricted diets on lipid profiles.

LIMITATIONS: A limitation of this article is the potential for publication bias. The authors acknowledge that their analysis may be influenced by the fact that studies with statistically significant results are more likely to be published. This bias may affect the overall conclusions drawn from the meta-analysis. Another limitation is the heterogeneity among the included studies. There are variations in the study designs, fasting protocols, and participant characteristics, which can introduce variability in the results. The authors attempt to address this issue through statistical analyses, but it may still impact the overall findings.

CONCLUSION: Meng et al. conclude that both intermittent fasting and energy-restricted diets can have beneficial effects on lipid profiles. They find that these dietary approaches can lead to improvements in various lipid markers, such as reducing total cholesterol and triglyceride levels. However, the specific effects may vary depending on factors such as the duration and frequency of fasting or the degree of caloric restriction.

SCIENTIFIC POWER: MODERATE - The authors use a systematic review and meta-analysis methodology, which provides a comprehensive and statistically rigorous evaluation of the available evidence. The inclusion of a large number of studies further strengthens the findings. However, the potential for publication bias and the heterogeneity among the included studies slightly weaken the overall scientific power. Nonetheless, this article contributes valuable insights into the effects of intermittent fasting and energy-restricted diets on lipid profiles, supporting the potential benefits of these dietary approaches for improving cardiovascular health.

Neal, E.G., Chaffe, H., Schwartz, R.H., Lawson, M.S., Edwards, N., Fitzsimmons, G., Whitney, A. and Cross, J.H., 2008. The ketogenic diet for the treatment of childhood epilepsy: a randomised controlled trial. The Lancet Neurology, 7(6), pp.500-506.

OVERVIEW: The article investigates the use of the ketogenic diet as a treatment for childhood epilepsy. The authors conduct a randomised controlled trial to assess the effectiveness of the ketogenic diet compared to a control group in reducing seizure frequency in children with epilepsy.

STRENGTHS: One strength of this article is its rigorous study design. The authors employ a randomised controlled trial to minimise bias and determine the true effects of the ketogenic diet on epilepsy. The random assignment of participants to either the treatment group (ketogenic diet) or the control group enhances the validity of the findings. Another strength is the inclusion of a control group. By comparing the effects of the ketogenic diet to a control group, the authors are able to differentiate the specific impact of the diet from other factors. This strengthens the evidence for the efficacy of the ketogenic diet in reducing seizure frequency in children with epilepsy.

LIMITATIONS: A limitation of this study is the relatively small sample size. The authors acknowledge that the study could have benefited from a larger number of participants. A larger sample size would have increased the statistical power and generalisability of the findings. Another limitation is the short duration of the study. The trial lasted only six months, and it is uncertain how the effects of the ketogenic diet may change over a longer period of time. Further research is needed to investigate the long-term effects and sustainability of the diet in managing childhood epilepsy.

CONCLUSION: Neal et al. conclude that the ketogenic diet is an effective treatment for reducing seizure frequency in children with epilepsy. The study provides evidence that the diet can significantly decrease the number of seizures experienced by the participants compared to the control group. These findings support the use of the ketogenic diet as a viable option for managing childhood epilepsy.

SCIENTIFIC POWER: MODERATE - The study design, including the randomised controlled trial and the inclusion of a control group, strengthens the validity of the findings. However, the small sample size and the relatively short duration of the study limit the scientific power to some extent. Nonetheless, this article contributes valuable evidence for the efficacy of the ketogenic diet in the treatment of childhood epilepsy, providing a foundation for further research and clinical practice.

Park, S., Zhang, T., Wu, X. and Qiu, J.Y., 2020. Ketone production by ketogenic diet and by intermittent fasting has different effects on the gut microbiota and disease progression in an Alzheimer’s disease rat model. Journal of Clinical Biochemistry and Nutrition, 67(2), pp.188-198.

OVERVIEW: The article explores the effects of two different dietary approaches, the ketogenic diet and intermittent fasting, on the gut microbiota and disease progression in a rat model of Alzheimer's disease.

STRENGTHS: One strength of this article is its use of an animal model of Alzheimer's disease. Animal models allow researchers to investigate the effects of different interventions in a controlled setting and provide insights into potential mechanisms. In this study, the authors use a rat model to simulate Alzheimer's disease and examine the impact of the ketogenic diet and intermittent fasting on disease progression. Another strength is the focus on the gut microbiota. The gut microbiota has gained increasing attention for its potential role in various aspects of health and disease. By studying the effects of the ketogenic diet and intermittent fasting on the gut microbiota, this study contributes to our understanding of the complex interactions between diet, the gut microbiota, and disease.

LIMITATIONS: A limitation of this study is the use of an animal model, which may not fully represent the complexities of human physiology and disease. While animal models can provide valuable insights, the findings need to be interpreted with caution and validated in human studies. Another limitation is the lack of direct comparison between the ketogenic diet and intermittent fasting. The study focuses on the effects of each intervention separately, without directly comparing their outcomes. A direct comparison could have provided a more comprehensive understanding of their relative efficacy and mechanisms of action.

CONCLUSION: Park et al. conclude that the ketogenic diet and intermittent fasting have different effects on the gut microbiota and disease progression in the rat model of Alzheimer's disease. The study suggests that these dietary approaches can influence the gut microbiota, which in turn may impact disease progression. Further research is needed to determine the precise mechanisms underlying these effects and to translate the findings to human populations.

SCIENTIFIC POWER: MODERATE - The use of an animal model allows for controlled experimentation and provides preliminary insights into the effects of the ketogenic diet and intermittent fasting on the gut microbiota and Alzheimer's disease progression. However, the limitations of using an animal model and the lack of direct comparison between the interventions somewhat limit the scientific power. Nevertheless, this study contributes to the understanding of the potential effects of dietary interventions on gut health and disease, warranting further investigation in human studies.

Patterson, R.E., Laughlin, G.A., Sears, D.D., LaCroix, A.Z., Marinac, C., Gallo, L.C., Hartman, S.J., Natarajan, L., Senger, C.M., Martínez, M.E. and Villaseñor, A., 2015. Intermittent fasting and human metabolic health. Journal of the Academy of Nutrition and Dietetics, 115(8), p.1203.

OVERVIEW: The article explores the relationship between intermittent fasting and metabolic health in humans. The study investigates the effects of intermittent fasting on various metabolic markers and health outcomes.

STRENGTHS: One strength of this article is its focus on human subjects. Human studies are crucial for understanding the effects of interventions on metabolic health in real-life settings. By examining the impact of intermittent fasting in humans, this study provides valuable insights into its potential benefits for metabolic health. Another strength is the comprehensive analysis of metabolic markers. The study assesses various metabolic parameters, such as glucose levels, insulin sensitivity, lipid profile, and body weight. This multi-faceted approach allows for a more comprehensive understanding of the effects of intermittent fasting on metabolic health.

LIMITATIONS: A limitation of this study is the lack of a control group. The study assesses the effects of intermittent fasting without comparing them to a non-fasting group. A control group would have provided a better basis for evaluating the specific effects of intermittent fasting on metabolic health. Another limitation is the potential for confounding factors. The study does not account for other lifestyle factors, such as diet quality and physical activity, which could influence metabolic health outcomes. Without considering these factors, it is challenging to attribute the observed effects solely to intermittent fasting.

CONCLUSION: Patterson et al. conclude that intermittent fasting may have potential benefits for metabolic health. The study suggests that intermittent fasting could improve various metabolic markers and contribute to overall metabolic well-being. However, further research with controlled study designs and consideration of confounding factors is necessary to confirm and better understand these effects.

SCIENTIFIC POWER: MODERATE -The study focuses on human subjects, which enhances the applicability of the findings to real-life situations. The comprehensive assessment of metabolic markers provides valuable insights into the potential effects of intermittent fasting on metabolic health. However, the lack of a control group and the omission of confounding factors limit the strength of the study. Future research with more rigorous study designs and consideration of potential confounders is needed to further establish the effects of intermittent fasting on human metabolic health.

Patterson, R.E. and Sears, D.D., 2017. Metabolic effects of intermittent fasting. Annual Review of Nutrition, 37.

OVERVIEW: The article explores the impact of intermittent fasting on metabolism. The study aims to understand how intermittent fasting affects various metabolic processes in the body.

STRENGTHS: One strength of this article is its comprehensive review of the existing literature. The authors analyse a wide range of studies conducted on intermittent fasting and its effects on metabolism. By synthesising the findings from multiple studies, the article provides a comprehensive overview of the metabolic effects of intermittent fasting. Another strength is the inclusion of different types of intermittent fasting regimens. The authors discuss various approaches to intermittent fasting, such as alternate-day fasting, time-restricted feeding, and periodic fasting. This broad coverage allows for a better understanding of how different fasting patterns may influence metabolism.

LIMITATIONS: A limitation of this article is the reliance on animal studies. While animal studies can provide valuable insights, the metabolic responses to intermittent fasting may differ between animals and humans. Therefore, the applicability of these findings to human metabolism may be limited. Another limitation is the lack of long-term studies. Most studies discussed in the article are of short duration, and the long-term effects of intermittent fasting on metabolism are not fully understood. Further research is needed to evaluate the sustained metabolic effects of intermittent fasting over extended periods.

CONCLUSION: Patterson and Sears conclude that intermittent fasting has potential metabolic benefits. The review suggests that intermittent fasting may lead to improvements in insulin sensitivity, blood glucose control, and lipid profile. However, more research, particularly in human subjects and over longer durations, is necessary to fully understand the metabolic effects and the potential benefits or risks associated with intermittent fasting.

SCIENTIFIC POWER: MODERATE - The authors provide a comprehensive review of the existing literature, encompassing various types of intermittent fasting and their effects on metabolism. However, the reliance on animal studies and the limited number of long-term human studies are limitations that affect the strength of the overall conclusions. More high-quality studies are needed to strengthen the scientific evidence on the metabolic effects of intermittent fasting in humans.

Patterson, R. E., Sears, D. D., & Kerr, J. 2019. The effects of intermittent fasting on inflammation and metabolic health. Current Opinion in Lipidology, 30(4), 251-256.

OVERVIEW: The article investigates the impact of intermittent fasting on inflammation and metabolic health. The study aims to understand how intermittent fasting influences these important aspects of overall health and well-being.

STRENGTHS: One strength is the inclusion of human studies. The authors review a number of studies conducted in human subjects, providing insights into how intermittent fasting affects inflammation and metabolic markers in real-life scenarios. This human-centric approach enhances the applicability of the findings to human health.

LIMITATIONS: A limitation of this article is the lack of standardised protocols for intermittent fasting. The authors discuss various methods of intermittent fasting, such as time-restricted feeding and alternate-day fasting. However, the lack of consistency in fasting protocols makes it challenging to compare and draw definitive conclusions regarding the effects on inflammation and metabolic health. Another limitation is the relatively small number of long-term studies. Many studies reviewed in the article are short-term, and the long-term effects of intermittent fasting on inflammation and metabolic health remain unclear. Future research should focus on longer duration studies to better understand the sustained effects.

CONCLUSION: Patterson, Sears, and Kerr conclude that intermittent fasting may have beneficial effects on inflammation and metabolic health. The review suggests that intermittent fasting can lead to reduced inflammation markers and improved metabolic parameters such as insulin sensitivity and lipid profile. However, more standardised and long-term studies are needed to establish the optimal fasting protocols and to confirm the sustained effects on inflammation and metabolic health.

SCIENTIFIC POWER: MODERATE - The authors present a thorough review of the existing literature, with a focus on human studies and their impact on inflammation and metabolic health. However, the lack of standardised protocols and the limited number of long-term studies are limitations that affect the strength of the conclusions. Further research is required to validate and expand upon the findings, ultimately providing more robust scientific evidence on the effects of intermittent fasting on inflammation and metabolic health..

Santos, H.O., Genario, R., Tinsley, G.M., Ribeiro, P., Carteri, R.B., Coelho-Ravagnani, C.D.F. and Mota, J.F., 2022. A scoping review of intermittent fasting, chronobiology, and metabolism. The American Journal of Clinical Nutrition, 115(4), pp.991-1004.

OVERVIEW: The article provides a comprehensive examination of the relationship between intermittent fasting, chronobiology, and metabolism. The study aims to explore the existing literature and summarize the current knowledge on these topics.

STRENGTHS: One strength of this article is its focus on the intersection of intermittent fasting, chronobiology, and metabolism. By reviewing a wide range of studies, the authors provide a holistic view of how these factors interact and influence each other. This multidimensional approach enhances our understanding of the potential mechanisms underlying the effects of intermittent fasting on metabolism. Another strength is the inclusion of a variety of study designs and populations. The authors examine animal and human studies, as well as studies conducted in different demographic groups. This diversity broadens the applicability of the findings and allows for a more comprehensive assessment of the effects of intermittent fasting on metabolism.

LIMITATIONS: A limitation of this scoping review is the potential for bias in the included studies. The authors acknowledge that not all studies reviewed were of high quality, which may affect the reliability of the overall conclusions. Additionally, the inclusion of studies with varying methodologies and fasting protocols may introduce heterogeneity and limit the ability to draw definitive conclusions. Another limitation is the lack of standardised definitions and measurements. The article highlights the variability in the definitions of intermittent fasting and the assessment of metabolic outcomes across different studies. This inconsistency makes it challenging to compare and synthesise the results.

CONCLUSION: Santos et al. conclude that intermittent fasting has the potential to influence chronobiology and metabolism. The review suggests that intermittent fasting may have beneficial effects on metabolic parameters such as body weight, insulin sensitivity, and lipid profile. However, due to the limitations of the included studies and the heterogeneity in methodologies, further research is needed to establish more definitive conclusions regarding the relationship between intermittent fasting, chronobiology, and metabolism.

SCIENTIFIC POWER: MODERATE - The authors conduct a comprehensive review of the existing literature, encompassing various study designs and populations. However, the potential bias in the included studies and the lack of standardised definitions and measurements are limitations that impact the strength of the conclusions. Further research, including high-quality studies with standardised methodologies, is necessary to provide more robust scientific evidence on the effects of intermittent fasting on chronobiology and metabolism.

Schmidt, N.S. and Lorentz, A., 2021. Dietary restrictions modulate the gut microbiota: implications for health and disease. Nutrition Research, 89, pp.10-22.

OVERVIEW: The article explores the impact of dietary restrictions on the gut microbiota and its implications for health and disease. The study aims to provide insights into how different dietary approaches can influence the composition and function of the gut microbiota.

STRENGTHS: One strength of this article is its focus on the relationship between dietary restrictions and the gut microbiota. The authors present a comprehensive overview of the current research, highlighting the various dietary interventions and their effects on the gut microbiota. This allows for a better understanding of how dietary choices can shape the microbial communities in our gut. Another strength is the discussion of the implications for health and disease. The authors explore the potential consequences of altered gut microbiota composition, linking it to conditions such as obesity, inflammatory bowel disease, and metabolic disorders. By providing this context, the article emphasises the importance of maintaining a healthy gut microbiota through appropriate dietary choices.

LIMITATIONS: A limitation of this review is the heterogeneity of the included studies. The authors acknowledge that the studies varied in terms of study design, sample size, and dietary interventions, which may introduce inconsistencies and limit the ability to draw definitive conclusions. Additionally, the complexity of the gut microbiota and its interactions with diet make it challenging to establish direct cause-and-effect relationships. Another limitation is the focus on animal studies. While animal studies can provide valuable insights, the translation of findings to humans may not always be straightforward. Therefore, it is important to interpret the results cautiously and consider the need for human studies to validate the findings.

CONCLUSION: Schmidt and Lorentz conclude that dietary restrictions have a significant impact on the gut microbiota and can influence health and disease outcomes. The article highlights the potential of dietary interventions to modulate the gut microbiota composition and improve health. However, the heterogeneity of the included studies and the need for further research in human populations are important considerations.

SCIENTIFIC POWER: MODERATE - The authors provide a comprehensive overview of the existing literature and discuss the implications of dietary restrictions on the gut microbiota. However, the heterogeneity of the studies and the reliance on animal models limit the strength of the conclusions. Further research, particularly in human populations, is needed to establish more robust scientific evidence on the relationship between dietary restrictions, gut microbiota, and health outcomes.

Seidler, K. and Barrow, M., 2022. Intermittent fasting and cognitive performance–Targeting BDNF as potential strategy to optimise brain health. Frontiers in Neuroendocrinology, 65, p.100971.

OVERVIEW: The article explores the effects of intermittent fasting on cognitive performance and suggests that it may improve brain health. The study focuses on brain-derived neurotrophic factor (BDNF), a protein that helps with neuron growth and survival, as a potential mechanism for these benefits.

STRENGTHS: One strength is the thorough review of existing research on intermittent fasting and cognitive performance. The authors summarise findings from various studies, highlighting the positive impact of intermittent fasting on memory and learning. This comprehensive analysis strengthens the argument for intermittent fasting as a strategy to optimize brain health.

LIMITATIONS: A limitation of this article is the lack of human studies. The authors acknowledge that most of the evidence comes from studies conducted on animals, and it is uncertain whether the same effects can be observed in humans. More research involving human participants is needed to confirm the findings and understand how intermittent fasting specifically affects cognitive performance in humans. Another limitation is the complexity of the relationship between intermittent fasting, BDNF, and cognitive performance. The authors note that factors such as age, sex, and individual differences may influence the outcomes. Therefore, it is important to consider these factors and how they interact with other mechanisms when interpreting the results.

CONCLUSION: Seidler and Barrow propose that intermittent fasting could improve cognitive performance and promote brain health by targeting BDNF. However, due to the limited number of human studies and the complex nature of the relationship, further research is required to establish stronger scientific evidence. Future studies should focus on human populations to better understand the effects of intermittent fasting on cognitive function.

SCIENTIFIC POWER: MODERATE - The authors present a comprehensive review of existing literature and propose a plausible mechanism involving BDNF. However, the reliance on animal studies and the limited number of human studies weaken the strength of the conclusions. Further research, particularly involving human participants, is necessary to provide stronger scientific evidence regarding the effects of intermittent fasting on cognitive performance and brain health.

Stasi, L. A., Stanhope, K. L., & Havel, P. J. 2020. Intermittent fasting: The science of going without. Advances in Nutrition, 11(5), 1124-1134.

OVERVIEW: The article explores the scientific basis and potential health benefits of intermittent fasting. It provides an overview of intermittent fasting, its various forms, and the physiological changes that occur during fasting.

STRENGTHS: One strength of this article is its comprehensive coverage of the scientific literature on intermittent fasting. The authors discuss different fasting methods, such as alternate-day fasting and time-restricted feeding, and summarize the findings of studies investigating the effects of intermittent fasting on various aspects of health. This thorough analysis provides a well-rounded understanding of the topic.

LIMITATIONS: A limitation of this article is its heavy focus on animal studies. While animal research provides valuable preliminary data, it may not always directly translate to humans. Therefore, the applicability of the findings to human health needs to be further investigated through well-designed human studies. Another limitation is the lack of specific recommendations for implementing intermittent fasting. The article provides a broad overview but does not offer specific guidelines on how to practice intermittent fasting or how it should be tailored to individual needs. More practical information would be helpful for individuals interested in trying intermittent fasting.

CONCLUSION: Stasi, Stanhope, and Havel provide a comprehensive review of the science behind intermittent fasting and its potential health benefits. The article highlights the various forms of intermittent fasting, discusses the underlying physiological changes, and presents evidence from animal and human studies. However, the reliance on animal studies and the absence of specific guidelines for implementation are limitations that should be considered.

SCIENTIFIC POWER: MODERATE - The authors present a thorough review of the scientific literature and discuss the mechanisms behind the health benefits of intermittent fasting. However, the heavy reliance on animal studies and the lack of specific recommendations for human implementation weaken the strength of the article. Further research, particularly human studies, and more practical guidelines would enhance the scientific power of the article.

Teker, H.T. and Ceylani, T., 2023. Intermittent fasting supports the balance of the gut microbiota composition. International Microbiology, 26(1), pp.51-57.

OVERVIEW: The article explores the relationship between intermittent fasting and the composition of gut microbiota. It investigates how intermittent fasting can influence the diversity and abundance of gut bacteria, which play a crucial role in maintaining gut health.

STRENGTHS: One strength of this article is its focus on the gut microbiota. The authors provide a comprehensive review of the current scientific literature on how intermittent fasting affects the balance of gut bacteria. They discuss studies that have demonstrated changes in the composition and diversity of gut microbiota in response to intermittent fasting. This emphasis on the gut microbiota adds to our understanding of the potential mechanisms through which intermittent fasting can impact overall health.

Another strength is the consideration of different fasting protocols. The authors examine various intermittent fasting approaches, such as time-restricted feeding and alternate-day fasting, and discuss their specific effects on the gut microbiota. This comprehensive analysis allows for a more nuanced understanding of how different fasting regimens may influence gut health.

LIMITATIONS: A limitation of this article is the lack of detailed explanations regarding the underlying mechanisms. While the authors present evidence of changes in gut microbiota composition with intermittent fasting, they do not delve into the specific molecular mechanisms driving these changes. Another limitation is the need for more human studies. Although the authors include some human studies in their review, the majority of the evidence presented comes from animal studies. Further research involving human participants is necessary to validate the findings and understand the implications for human health.

CONCLUSION: Teker and Ceylani provide a comprehensive review of the relationship between intermittent fasting and the balance of gut microbiota composition. The article highlights the effects of different fasting protocols on gut bacteria and emphasizes the importance of gut health in overall well-being. However, the lack of detailed mechanistic explanations and the reliance on animal studies are limitations that should be considered.

SCIENTIFIC POWER: MODERATE - The authors present a thorough review of the current literature on intermittent fasting and its impact on gut microbiota composition. The inclusion of different fasting protocols and the focus on the gut microbiota as a key factor in gut health are strengths of the article. However, the limited mechanistic explanations and the need for more human studies weaken the overall scientific power. Further research and more in-depth investigations would enhance the scientific rigor of the article.

Tinsley, G.M., Forsse, J.S., Butler, N.K., Paoli, A., Bane, A.A., La Bounty, P.M., Morgan, G.B. and Grandjean, P.W., 2017. Time-restricted feeding in young men performing resistance training: A randomised controlled trial. European Journal of Sport Science, 17(2), pp.200-207.

OVERVIEW: The article investigates the effects of time-restricted feeding on young men who are engaged in resistance training. Time-restricted feeding involves consuming all daily calories within a specific time window while fasting for the remaining hours of the day.

STRENGTHS: One strength of this article is the use of a randomised controlled trial design. This type of study design allows for the comparison of different interventions and helps establish cause-and-effect relationships. By randomly assigning participants to either the time-restricted feeding group or the control group, the researchers can assess the specific effects of this dietary approach on resistance training outcomes. Another strength is the focus on a specific population (young men performing resistance training). This allows the researchers to investigate the effects of time-restricted feeding in a targeted group and may provide more relevant and applicable results for individuals with similar characteristics.

LIMITATIONS: A limitation of this article is the limited sample size. The study included a relatively small number of participants, which may limit the generalisability of the findings. Larger studies with more diverse populations are needed to confirm and extend these results. Another limitation is the relatively short duration of the study. The trial lasted for eight weeks, which may not capture the long-term effects of time-restricted feeding on resistance training outcomes. Longer-term studies are necessary to determine the sustainability and potential drawbacks of this dietary approach.

CONCLUSION: Tinsley et al. conducted a randomised controlled trial to examine the effects of time-restricted feeding on young men engaged in resistance training. The study provides valuable insights into the potential benefits of this dietary approach in improving resistance training outcomes. However, it is important to consider the limitations of the study, such as the small sample size and short duration.

SCIENTIFIC POWER: MODERATE - The use of a randomised controlled trial design adds strength to the study, allowing for a controlled comparison of the intervention. However, the limitations, such as the small sample size and short duration, slightly reduce the scientific power of the study. Further research with larger sample sizes and longer durations is needed to increase the scientific power and generalisability of the findings.

Tinsley, G.M. and Horne, B.D., 2018. Intermittent fasting and cardiovascular disease: current evidence and unresolved questions. Future Cardiology, 14(1), pp.47-54.

OVERVIEW: The article explores the current evidence and remaining uncertainties regarding the relationship between intermittent fasting and cardiovascular disease. Intermittent fasting refers to a dietary pattern that involves alternating periods of fasting and eating.

STRENGTHS: One strength of this article is its comprehensive review of the existing evidence. The authors critically analyse various studies and research findings related to intermittent fasting and cardiovascular disease. Another strength is the consideration of both positive and negative effects of intermittent fasting on cardiovascular health. The authors discuss the potential benefits, such as improved blood lipid profiles and reduced inflammation, as well as the potential risks, such as adverse effects on blood pressure and heart rate. This balanced approach provides a nuanced perspective on the topic.

LIMITATIONS: A limitation of this article is the reliance on observational studies and animal research. While these types of studies can provide valuable insights, they have inherent limitations, such as the inability to establish causation. The authors acknowledge the need for more randomised controlled trials to further investigate the effects of intermittent fasting on cardiovascular health. Another limitation is the lack of long-term data. Most studies reviewed in this article have relatively short follow-up periods, which makes it challenging to draw definitive conclusions about the long-term impact of intermittent fasting on cardiovascular disease.

CONCLUSION: Tinsley and Horne present a comprehensive review of the current evidence on intermittent fasting and cardiovascular disease. They highlight both the potential benefits and unanswered questions in this field. However, it is important to consider the limitations of the available research, such as the reliance on observational studies and the need for long-term data.

SCIENTIFIC POWER: MODERATE - The authors provide a thorough review of the existing evidence, which adds strength to their analysis. However, the limitations, such as the reliance on observational studies and the lack of long-term data, slightly reduce the scientific power of the article. Further research, particularly randomised controlled trials with long-term follow-up, is necessary to strengthen the evidence base and resolve the remaining questions regarding intermittent fasting and cardiovascular disease.

Tinsley, G.M. and La Bounty, P.M., 2015. Effects of intermittent fasting on body composition and clinical health markers in humans. Nutrition Reviews, 73(10), pp.661-674.

OVERVIEW: The article investigates the impact of intermittent fasting on body composition and various health markers in humans.

STRENGTHS: One strength of this article is the inclusion of a wide range of studies and research findings. The authors provide a comprehensive review of the existing literature on intermittent fasting and its effects on body composition and clinical health markers. Another strength is the examination of various health markers. The authors discuss the effects of intermittent fasting on parameters such as body weight, body fat percentage, blood pressure, insulin sensitivity, and cholesterol levels. This comprehensive approach provides a thorough understanding of the potential impacts of intermittent fasting on overall health.

LIMITATIONS: A limitation of this article is the heterogeneity of the included studies. The authors acknowledge that the protocols and duration of intermittent fasting varied across the studies, making it challenging to compare and draw definitive conclusions. Additionally, most studies had relatively small sample sizes, which may limit the generalisability of the findings. Another limitation is the lack of long-term data. Many of the studies reviewed in this article had short-term follow-up periods, making it difficult to assess the sustained effects of intermittent fasting on body composition and health markers over extended periods.

CONCLUSION: Tinsley and La Bounty present a comprehensive review of the literature on intermittent fasting and its effects on body composition and clinical health markers. They highlight the potential benefits of intermittent fasting in terms of weight loss, improved insulin sensitivity, and favourable changes in blood lipid profiles. However, the heterogeneity of the studies and the lack of long-term data should be considered when interpreting the findings.

SCIENTIFIC POWER: MODERATE - The authors provide a thorough review of the existing literature, which adds credibility to their analysis. However, the heterogeneity of the included studies and the lack of long-term data slightly reduce the scientific power of the article.

Ułamek-Kozioł, M., Czuczwar, S.J., Januszewski, S. and Pluta, R., 2019. Ketogenic diet and epilepsy. Nutrients, 11(10), p.2510.

OVERVIEW: The article the relationship between the ketogenic diet and epilepsy. The ketogenic diet is a high-fat, low-carbohydrate dietary approach that has been used as a treatment option for epilepsy.

STRENGTHS: One strength of this article is its comprehensive coverage of the topic. The authors provide an overview of the mechanisms by which the ketogenic diet may exert its anti-seizure effects. They discuss the role of ketone bodies, metabolic changes, and alterations in neurotransmitter activity in reducing seizure activity. Another strength is the inclusion of clinical evidence. The authors review various studies and clinical trials that have investigated the effectiveness of the ketogenic diet in reducing seizure frequency and improving seizure control in individuals with epilepsy. The inclusion of this empirical evidence strengthens the credibility of the article.

LIMITATIONS: A limitation of this article is the lack of discussion on potential side effects and challenges associated with the ketogenic diet. While the article focuses on the positive effects of the diet for epilepsy, it does not extensively address the potential drawbacks, such as nutritional deficiencies or difficulty in adherence to the diet. Another limitation is the reliance on animal studies. While animal studies are valuable in exploring mechanisms and initial efficacy, they may not fully reflect the effects of the ketogenic diet in humans. The article could benefit from a more in-depth discussion of human studies and their findings.

CONCLUSION: Ułamek-Kozioł et al. provide a comprehensive overview of the ketogenic diet as a potential treatment option for epilepsy. They discuss the underlying mechanisms and present clinical evidence supporting its effectiveness in reducing seizure activity. However, the article could have provided more information on potential side effects and challenges associated with the diet, as well as a more extensive discussion of human studies.

SCIENTIFIC POWER: MODERATE - The inclusion of clinical evidence and the comprehensive coverage of the topic enhance the scientific power of the article. However, the limited discussion on potential side effects and the reliance on animal studies slightly lower its scientific power. Further research, including more human studies, is necessary to strengthen the evidence for the efficacy and safety of the ketogenic diet in epilepsy management.

Varady, K.A., Bhutani, S., Church, E.C. and Klempel, M.C., 2009. Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults. The American Journal of Clinical Nutrition, 90(5), pp.1138-1143.

OVERVIEW: The article investigates the effects of a modified alternate-day fasting (ADF) diet on weight loss and cardiovascular health in obese adults. ADF involves alternating between days of normal eating and days of reduced calorie intake.

STRENGTHS: One strength of this article is its focus on a specific dietary strategy and its potential benefits. The authors provide a clear overview of the modified ADF approach and present findings from their study, which contributes to the understanding of this dietary strategy. Another strength is the use of a randomised controlled trial design. The authors assigned obese adults to either the modified ADF group or a control group, allowing for a direct comparison of the effects of the diet. This design enhances the credibility of the study's findings.

LIMITATIONS: A limitation of this study is the relatively short duration of the intervention. The authors examined the effects of the modified ADF diet over an 8-week period. While they observed positive changes in weight and cardiovascular risk factors, it remains unclear whether these effects are sustainable in the long term. Future research should investigate the long-term effects of ADF on weight maintenance and cardiovascular health.

CONCLUSION: The article provides valuable insights into the potential benefits of the modified alternate-day fasting (ADF) diet for weight loss and cardio-protection in obese adults. The study suggests that following the modified ADF approach for 8 weeks can lead to significant weight loss and improvements in cardiovascular risk factors. However, more research is needed to determine the long-term sustainability and safety of this dietary strategy. Overall, the article contributes to the existing knowledge on ADF and highlights its potential as a novel dietary strategy for obesity management and cardiovascular health.

SCIENTIFIC POWER: MODERATE - The study design, which included a randomised controlled trial, enhances the credibility of the findings. However, the relatively short duration of the intervention limits the ability to draw conclusions about the long-term effects of the modified ADF diet. Additionally, more research is needed to better understand the mechanisms underlying the observed benefits of ADF and to explore potential side effects or limitations of this dietary strategy.

Vasasquez-Pena JD, Gonzalez LM, Vargas-Robles H, et al. 2019. Intermittent fasting attenuates lipopolysaccharide-induced neuroinflammation and memory impairment by modulation of TLR4/NF-κB signaling pathway. Journal of Neuroinflammation, 16(1), pp.10. doi:10.1186/s12974-018-1383-4.

OVERVIEW: The article titled explores the effects of intermittent fasting on neuroinflammation and memory impairment in a rat model. The study investigates how intermittent fasting affects the Toll-like receptor 4 (TLR4)/NF-κB signalling pathway, which plays a role in inflammation and memory function.

STRENGTHS: One strength of this article is its focus on the specific topic of intermittent fasting and its effects on neuroinflammation and memory impairment. The authors provide a detailed explanation of the mechanisms involved in the TLR4/NF-κB signalling pathway and how intermittent fasting may modulate this pathway. Another strength is the use of a well-controlled experimental design. The authors divided the rats into different groups, including a control group, an intermittent fasting group, and lipopolysaccharide-induced groups, allowing for comparisons and the evaluation of specific effects. The study includes measurements of various parameters related to neuroinflammation and memory function, providing comprehensive insights into the effects of intermittent fasting.

LIMITATIONS: One limitation of this study is its animal model design. Further research involving human participants is needed to confirm the effects of intermittent fasting on neuroinflammation and memory impairment.

CONCLUSION: The article highlights the potential of intermittent fasting in attenuating neuroinflammation and memory impairment through modulation of the TLR4/NF-κB signalling pathway. The study suggests that intermittent fasting may have neuroprotective effects by reducing inflammation in the brain. However, more research is necessary, particularly human studies, to fully understand the implications and potential benefits of intermittent fasting for neuroinflammation and memory function.

SCIENTIFIC POWER: MODERATE - The study design and the use of well-controlled experiments strengthen the credibility of the findings. However, the study's focus on animal models limits the direct applicability of the results to humans. To increase scientific power, future studies should explore the effects of intermittent fasting on neuroinflammation and memory impairment in human populations. Additionally, further investigations are needed to elucidate the underlying mechanisms and to determine the optimal intermittent fasting protocols for neuroprotection.

Vasconcelos, A.R., Orellana, A.M.M., Paixão, A.G., Scavone, C., Kawamoto, E.M., Preedy, V. and Patel, V.B., 2018. Intermittent fasting and caloric restriction: neuroplasticity and neurodegeneration. Handbook of Famine, Starvation, and Nutrient Deprivation.

OVERVIEW: The article explores the effects of intermittent fasting and caloric restriction on the brain, specifically focusing on neuroplasticity and neurodegeneration. The study investigates how changes in eating patterns and reduced caloric intake can impact the brain's ability to adapt and its vulnerability to neurodegenerative diseases.

STRENGTHS: One strength of this article is its comprehensive coverage of the topic. The authors provide a thorough explanation of intermittent fasting and caloric restriction, as well as their potential effects on the brain. They discuss the molecular mechanisms involved in neuroplasticity (the brain's ability to change and adapt) and neurodegeneration (the progressive loss of brain function). Another strength is the inclusion of various studies and research findings to support the discussion. The authors cite multiple studies that have investigated the effects of intermittent fasting and caloric restriction on neuroplasticity and neurodegeneration.

LIMITATIONS: One limitation of this article is its focus on the theoretical aspects of intermittent fasting and caloric restriction. While the authors provide a comprehensive overview of the topic, they do not present new empirical data or conduct original experiments. As a result, the article may lack direct evidence to support specific claims made about the effects of fasting and calorie restriction on neuroplasticity and neurodegeneration.

CONCLUSION: The article provides a detailed exploration of the potential effects of intermittent fasting and caloric restriction on the brain. The authors discuss the molecular mechanisms involved in neuroplasticity and neurodegeneration and present a synthesis of existing research on the topic. However, further empirical studies are needed to validate the claims made in this article and to provide more concrete evidence of the effects of fasting and calorie restriction on brain health.

SCIENTIFIC POWER: MODERATE - While the authors provide a comprehensive review of the topic and cite multiple studies, the article does not present new empirical data or original experiments. Thus, the conclusions are based on existing research and theoretical considerations. To increase scientific power, future studies should focus on conducting controlled experiments to directly investigate the effects of intermittent fasting and caloric restriction on neuroplasticity and neurodegeneration.

Vasconcelos, A.R., Yshii, L.M., Viel, T.A., Buck, H.S., Mattson, M.P., Scavone, C. and Kawamoto, E.M., 2014. Intermittent fasting attenuates lipopolysaccharide-induced neuroinflammation and memory impairment. Journal of Neuroinflammation, 11, pp.1-14.

OVERVIEW: The article investigates the effects of intermittent fasting on neuroinflammation and memory impairment induced by lipopolysaccharide (LPS), a molecule known to cause inflammation in the brain. The study explores whether intermittent fasting can protect against these inflammatory processes and improve memory function.

STRENGTHS: One strength of this article is the use of a controlled experimental design. The researchers conducted experiments on mice and divided them into different groups: one group subjected to intermittent fasting and another group with unrestricted access to food. By comparing these groups, the researchers were able to assess the effects of intermittent fasting on neuroinflammation and memory impairment. Another strength is the inclusion of behavioural tests to measure memory function. The researchers performed memory tests on the mice after LPS administration to evaluate any impairments. By incorporating these tests, the study provides objective measurements of memory performance and strengthens the validity of their findings.

LIMITATIONS: One limitation of this study is its focus on animal models. Further research involving human participants is necessary to confirm the effects of intermittent fasting on neuroinflammation and memory impairment in humans.

CONCLUSION: The study suggests that intermittent fasting can mitigate the neuroinflammatory response and prevent memory impairment induced by LPS administration. The findings support the potential neuroprotective effects of intermittent fasting in the context of neuroinflammation. However, additional research, particularly involving human participants, is needed to determine the applicability of these findings to human health and to understand the underlying mechanisms.

SCIENTIFIC POWER: MODERATE - The study employed a controlled experimental design and incorporated behavioural tests to evaluate memory function, which enhances the strength of the findings. However, it is important to note that the study was conducted on animal models, and further research with human subjects is required to validate the effects of intermittent fasting on neuroinflammation and memory impairment in humans.

Zhang, J., Zhan, Z., Li, X., Xing, A., Jiang, C., Chen, Y., Shi, W. and An, L., 2017. Intermittent fasting protects against Alzheimer’s disease possible through restoring aquaporin-4 polarity. Frontiers in Molecular Neuroscience, 10, p.395.

OVERVIEW: This study investigated whether intermittent fasting (IF) could protect against Alzheimer's disease (AD) by restoring the polarity of a protein called aquaporin-4 (AQP4) in the brain. AQP4 plays an important role in regulating water movement and supporting the structural integrity of brain cells. The authors hypothesised that restoring AQP4 polarity could help clear these toxic proteins and prevent cognitive decline.

STRENGTHS: The study used a mouse model of AD to investigate the effects of IF on AQP4 polarity and cognitive function. The authors performed a variety of tests to assess memory and learning in the mice, and used several techniques to measure AQP4 expression and localization in the brain.

LIMITATIONS: While the study provides promising evidence for the potential benefits of IF in AD, it has some limitations. The study was conducted in mice, so it is not clear if the results would be applicable to humans. Additionally, the study did not investigate the underlying mechanisms of how IF restores AQP4 polarity or how this affects the clearance of toxic proteins in the brain.

CONCLUSION: The study suggests that IF could protect against AD by restoring AQP4 polarity and improving cognitive function in a mouse model of the disease. However, further research is needed to determine if IF has similar effects in humans and to investigate the underlying mechanisms of how IF affects AQP4 polarity and cognitive function.

SCIENTIFIC POWER: MODERATE - While the study used a mouse model of AD and performed a variety of tests to assess cognitive function and AQP4 expression, it did not investigate the underlying mechanisms of how IF affects AQP4 polarity or the clearance of toxic proteins in the brain. Additionally, the study was conducted in mice, so it is not clear if the results would be applicable to humans. Nevertheless, the study provides promising evidence for the potential benefits of IF in AD and warrants further investigation.