This page features 50 unique references to scientific papers.

Research analysis by and verified by the Research Team. Last updated on Apr 18, 2018.

Summary of Fasting

Primary Information, Benefits, Effects, and Important Facts

In Progress

This page on Fasting is currently marked as in-progress. We are still compiling research.

The physiology of fasting

Metabolism (phases I, II, III)

Substrate utilization

Glycogen, glucose, fatty acids, glycerol, ketones, triglycerides, cholesterol, amino acids, ammonia / urea / uric acid

Hormonal change

Insulin, glucagon, glucocorticoids, thyroid hormones, GI peptides, adiponectin, leptin, ghrelin, catecholamines

Nutrient / energy sensing



Why and when do animals fast?

Seasonal (hibernation / aestivation), natural period in life (migration / molting / reproduction / development), food shortage, feeding tactics (sit-and-wait)

Evolutionary considerations for humans and fasting

Body composition

Effects on fat-free mass, fat mass, and water balance

Immune system

Effects on innate and adaptive immunity

Adjunct to cancer treatment

Athletic performance


Effects on cognitive function and neurodegeneration


Changes with fasting and refeeding

Gene expression (might be more appropriate within each section)


Frequently Asked Questions

Questions and answers regarding Fasting

Q: Do I need to eat six times a day to keep my metabolism high?

A: Eating food six times a day, or very high meal frequency, does not seem to increase the overall metabolic rate more than simply eating three times a day. If such a meal frequency can help you feel better on a diet then it can be useful but it alone won't cause weight loss or prevent weight gain.

Read full answer to "Do I need to eat six times a day to keep my metabolism high?"

Q: Could fasting help treat MS symptoms?

A: We analyze a study that says fasting could help with MS.

Read full answer to "Could fasting help treat MS symptoms?"

Q: Is it really that bad to skip breakfast?

Read full answer to "Is it really that bad to skip breakfast?"

Q: The lowdown on intermittent fasting

A: We analyze the research on intermittent fasting and how it impacts your health.

Read full answer to "The lowdown on intermittent fasting"

Scientific Support & Reference Citations

Via HEM and FAQ:

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  4. Taylor MA, Garrow JS. Compared with nibbling, neither gorging nor a morning fast affect short-term energy balance in obese patients in a chamber calorimeter. Int J Obes Relat Metab Disord. (2001)
  5. Verboeket-van de Venne WP, Westerterp KR. Influence of the feeding frequency on nutrient utilization in man: consequences for energy metabolism. Eur J Clin Nutr. (1991)
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  8. Verboeket-van de Venne WP, Westerterp KR. Frequency of feeding, weight reduction and energy metabolism. Int J Obes Relat Metab Disord. (1993)
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  17. Shariatpanahi ZV, et al. Effect of Ramadan fasting on some indices of insulin resistance and components of the metabolic syndrome in healthy male adults. Br J Nutr. (2008)
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  20. Food intake patterns and body mass index in observational studies.
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  23. International Society of Sports Nutrition position stand: meal frequency.
  24. Observational Studies Refuting the Effectiveness of Increased Meal Frequency on Weight loss/Fat loss.
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  37. Geliebter A, et al. Skipping breakfast leads to weight loss but also elevated cholesterol compared with consuming daily breakfasts of oat porridge or frosted cornflakes in overweight individuals: a randomised controlled trial. J Nutr Sci. (2014)
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  39. Jakubowicz D, et al. Fasting until noon triggers increased postprandial hyperglycemia and impaired insulin response after lunch and dinner in individuals with type 2 diabetes: a randomized clinical trial. Diabetes Care. (2015)
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  42. Moro T, et al. Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. J Transl Med. (2016)
  43. Farshchi HR, Taylor MA, Macdonald IA. Deleterious effects of omitting breakfast on insulin sensitivity and fasting lipid profiles in healthy lean women. Am J Clin Nutr. (2005)
  44. Mattson MP, Longo VD, Harvie M. Impact of intermittent fasting on health and disease processes. Ageing Res Rev. (2016)
  45. Tinsley GM, La Bounty PM. Effects of intermittent fasting on body composition and clinical health markers in humans. Nutr Rev. (2015)
  46. Longo VD, Mattson MP. Fasting: molecular mechanisms and clinical applications. Cell Metab. (2014)
  47. Masoro EJ. Overview of caloric restriction and ageing. Mech Ageing Dev. (2005)
  48. Mattison JA, et al. Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study. Nature. (2012)
  49. Horne BD, Muhlestein JB, Anderson JL. Health effects of intermittent fasting: hormesis or harm? A systematic review. Am J Clin Nutr. (2015)
  50. Wei M, et al. Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease. Sci Transl Med. (2017)