Intermittent fasting (IF) is an umbrella term for various diets that cycle between a period of fasting and non-fasting during a defined period. Intermittent fasting can also be used with calorie restriction for weight loss.[1]
Variations
Most popular intermittent fasting protocols can be grouped into 2 categories: whole-day fasting and time-restricted feeding (TRF).
- Whole-day fasting involves regular one-day fasts. The strictest form would be Alternate day fasting (ADF). This involves a 24-hour fast followed by a 24-hour non-fasting period.[2] The 5:2 diet allows the consumption of 500–600 calories on fasting days.[3][4][5][6]
- Time-restricted feeding (TRF) involves eating only during a certain number of hours each day.[7] A common form of TRF involves fasting for 16 hours each day and only eating during the remaining 8 hours, typically on the same schedule each day.[8] A more lax regime would be twelve hours of fasting and a twelve-hour eating window, or a stricter form would be to eat one meal per day, which would involve around 23 hours of fasting per day.[9]
Recommendations vary on what can be consumed during the fasting periods. Some would say only water, others would allow tea or coffee (without milk or sugar) or zero-calories drinks with artificial sweeteners. Yet others would allow "modified fasting" with limited caloric intake (e.g., 20% of normal) during fasted periods rather than none at all.[2]
The 5:2 diet became popular in the UK in 2012[6][10][11] after the BBC2 television Horizon documentary Eat, Fast and Live Longer.[12][13][14] It then spread to the rest of Europe and to the US.[15]
According to NHS Choices as of 2012, people considering the 5:2 diet should first consult a physician, as fasting can sometimes be unsafe.[16] In the UK, the tabloid press reported on research claiming the 5:2 diet could reduce the risk of breast cancer, but there is inadequate evidence for such statements.[17] A news item in the Canadian Medical Association Journal expressed concern that promotional material for the diet showed people eating high-calorie food such as hamburgers and chips, and that this could encourage binge eating since the implication was that "if you fast two days a week, you can devour as much junk as your gullet can swallow during the remaining five days".[18]
Research
A 2014 review[19] described that intermittent fasting has not been studied in children, the elderly, or the underweight, and could be harmful in these populations. It also suggested that people choosing to fast for periods of time greater than 24 hours should be monitored by a physician, as changes to the gastrointestinal system or circadian rhythm can occur.[19] The review concluded that fasting is unlikely to have much effect on conditions other than obesity, such as aging or other chronic condition, unless combined with moderate calorie restriction and a plant-based diet such as the Mediterranean diet.[19]
According to another 2014 review, intermittent fasting can lead to weight loss, though long-term calorie restriction can lead to slightly more weight loss compared to intermittent fasting.[20]
Intermittent fasting has been found to have beneficial effects in healthy and obese adults for reducing basal insulin, triglycerides, and blood glucose in fasting periods shorter than 24 hours. [21]
See also
References
- ^ Mager, D. E. (1 April 2006). "Caloric restriction and intermittent fasting alter spectral measures of heart rate and blood pressure variability in rats". The FASEB Journal. 20 (6): 631–637. doi:10.1096/fj.05-5263com. PMID 16581971.
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: CS1 maint: unflagged free DOI (link) - ^ a b Varady, K. A. (2011). "Intermittent versus daily calorie restriction: Which diet regimen is more effective for weight loss?". Obesity Reviews. 12 (7): e593–601. doi:10.1111/j.1467-789X.2011.00873.x. PMID 21410865.
- ^ Fisher, Roxanne (1 June 2016). "What is the 5:2 diet?". BBC GoodFood, Worldwide.
- ^ Mosley, Michael. "The 5:2 diet: can it help you lose weight and live longer?". The Telegraph. Retrieved 11 September 2012.
With this regimen you eat what you want five days a week...
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(help) - ^ Emma Young, New Scientist (2 January 2013). "Hunger games: The new science of fasting". Thomasville Times Enterprise. Retrieved 3 January 2013.
...I am allowed to eat whatever I want on the five non-fast days.
- ^ a b "How to diet". Live Well - NHS Choices. UK National Health Service. 9 December 2011. Retrieved 10 February 2014.
- ^ Rothschild, Jeff; Hoddy, Kristin K.; Jambazian, Pera; Varady, Krista A. (2014-05-01). "Time-restricted feeding and risk of metabolic disease: a review of human and animal studies". Nutrition Reviews. 72 (5): 308–318. doi:10.1111/nure.12104. ISSN 0029-6643.
- ^ Moro, Tatiana; Tinsley, Grant; Bianco, Antonino; Marcolin, Giuseppe; Pacelli, Quirico Francesco; Battaglia, Giuseppe; Palma, Antonio; Gentil, Paulo; Neri, Marco (2016). "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". Journal of Translational Medicine. 14: 290. doi:10.1186/s12967-016-1044-0. ISSN 1479-5876. PMC 5064803. PMID 27737674.
{{cite journal}}
: CS1 maint: unflagged free DOI (link) - ^ Stote, KS; Baer, DJ; Spears, K; Paul, DR; Harris, GK; Rumpler, WV; Strycula, P; Najjar, SS; Ferrucci, L; Ingram, D. K.; Longo, D. L.; Mattson, M. P. (2007). "A controlled trial of reduced meal frequency without caloric restriction in healthy, normal-weight, middle-aged adults" (PDF). The American Journal of Clinical Nutrition. 85 (4): 981–8. PMC 2645638. PMID 17413096.
- ^ Trueland J (2013). "Fast and effective?". Nursing Standard (Pictorial). 28 (16): 26–27. doi:10.7748/ns2013.12.28.16.26.s28.
- ^ Healy A (11 June 2013). "Dietitians warn against fad diets". Irish Times.
- ^ Mosley, Michael (5 September 2012). "Eat, Fast & Live Longer". Horizon. Episode 49x03. BBC. 2. Retrieved 10 February 2014.
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suggested) (help) - ^ Stone, Philip (22 February 2013). "Public appetite for fasting grows: four intermittent fasting titles earn bestseller status; Mary Berry beats Paul Hollywood in a baking battle; and children's sales slump due to a calendar quirk". The Bookseller: 17.
- ^ Quinn C (2 May 2013). "Latest dieting fad not yet proven safe, warn nutritionists". Irish Independent. p. 7.
- ^ "The UK's Hot New 5:2 Diet Craze Hits The U.S. - Weight Loss Miracle?". Forbes. 17 May 2013. Retrieved 10 February 2014.
- ^ "News analysis: Does the 5:2 intermittent fasting diet work?". Health News. UK National Health Service - NHS Choices. May 2013. Retrieved 23 November 2016.
- ^ "Could 5:2 diet play a role in preventing breast cancer?". NHS Choices. 17 June 2016.
- ^ Collier R (2013). "Intermittent fasting: the science of going without". CMAJ. 185 (9): E363–4. doi:10.1503/cmaj.109-4451. PMC 3680567. PMID 23569168.
- ^ a b c Mattson, MP (February 4, 2014). "Fasting: molecular mechanisms and clinical applications". Cell Metabolism. 19 (1932–7420): 181–92. doi:10.1016/j.cmet.2013.12.008. PMC 3946160. PMID 24440038.
- ^ Barnosky, A. R.; Hoddy, K. K.; Unterman, T. G.; Varady, K. A. (2014). "Intermittent fasting vs daily calorie restriction for type 2 diabetes prevention: A review of human findings". Translational Research. 164 (4): 302–11. doi:10.1016/j.trsl.2014.05.013. PMID 24993615.
- ^ https://www.ncbi.nlm.nih.gov/pubmed/29086496