Intermittent Fasting

Is this popular diet trend right for you?
Intermittent Fasting

Intermittent fasting is a trendy diet strategy that has been around for ages, literally.  Researchers believe that the human genome evolved from 600,000 BC to 25,000 BC (de Azevedo, Ikeoka, & Caramelli, 2013).  During this time, humans were hunter-gathers who experienced significant energy oscillations; sometimes, there was plenty of food, but other times there was not.  This constant flux in energy availability shaped the development of the human genome to regulate metabolism for efficient energy use and increased fat storage (de Azevedo et al., 2013; De Cabo & Mattson, 2019).  Today, while the human genome remains mostly unaltered, our environment has changed drastically.  Humans no longer face food shortage, lead sedentary lives, and eat at least three meals per day.  However, there is little to no scientific evidence to support the notion that eating at least three meals per day is optimal for health (Caramoci et al., 2016).  Indeed, eating at least three meals per day, every day, is, arguably, not even in alignment with our genome’s design (de Azevedo et al., 2013).  At the same time, the health consequences for overfeeding are dire since overfeeding seriously affects human morbidity and mortality (Caramoci et al., 2016).  Therefore, bodyweight reduction is a valuable tool to improve health, enhance the quality of life, and reduce public health outcomes.  Caloric restriction is one of the most efficient ways to lose weight, but caloric restriction may also improve the health of normal-weight people.  Caloric restriction through intermittent fasting, which is fasting and eating only for designated periods, may mimic the ancestral eating patters for which our genome was designed.  Many find fasting is a model of caloric restriction that is easier to adhere to than general calorie restriction (Barnosky, Hoddy, Unterman, & Varady, 2014).

There are three popular intermittent fasting models; alternate day fasting, 5:2 intermittent fasting in which eating is unrestricted five days per week and restricted to 500 calories per day two days per week, and daily time-restricted feeding (De Cabo & Mattson, 2019).  Intermittent fasting does not require adherence to a specific diet, only to nutrient timing alternating “feed” days or times with “fast” days or times (Barnosky et al., 2014).  More research is required to determine if one fasting model is more beneficial than another.  However, it is worth considering that one of the ideas behind intermittent fasting is that the more time one spends fasting, the better since ketosis is achieved in the fasting state (Aragon et al., 2017).  Nonetheless, intermittent fasting a more viable dieting option for some people compared with caloric restriction, and ketosis may be easier to achieve through intermittent fasting. 

One incredible benefit of intermittent fasting is how our cells respond to periods without food.  Researchers believe cells respond to intermittent fasting by engaging in a coordinated adaptive stress response that promotes DNA repair, down-regulation of inflammation, protein quality control, mitochondrial biogenesis and autophagy, and increased expression of antioxidant defenses (De Cabo & Mattson, 2019).  This cellular pathway, also known as ketosis, is mostly untapped in people who overeat or are sedentary.  Other benefits of intermittent fasting disassociated with weight loss include improved glucose regulation, increased abdominal fat loss, and improved blood pressure and heart rate efficacy during endurance training.  While the effects of fasting on athletic performance is a field that requires more study, some research suggests intermittent fasting does not cause muscle loss or decrease muscle force generation (Caramoci et al., 2016).  Research shows that intermittent fasting promotes longevity and increase the life span of humans (De Cabo & Mattson, 2019).  Brain health and cognitive ability may improve through intermittent fasting (Cherif, Roelands, Meeusen, & Chamari, 2016).  The benefits of intermittent fasting are plentiful for many populations. 


Aragon, A. A., Schoenfeld, B. J., Wildman, R., Kleiner, S., VanDusseldorp, T., Taylor, L., … Antonio, J. (2017). International society of sports nutrition position stand: Diets and body composition. Journal of the International Society of Sports Nutrition, 14(1), 1–20.

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. TRSL, 164(4), 302–311.

Caramoci, A., Mitoiu, B., Pop, M., Mazilu, V., Vasilescu, M., Inonescu, A. M., & Eugenia, R. (2016). Is intermittent fasting a scientifically-based dietary method? Journal of Romanian Sports Medicine Society, XII(2), 2747–2755.

Cherif, A., Roelands, B., Meeusen, R., & Chamari, K. (2016). Effects of intermittent fasting, caloric restriction, and Ramadan intermittent fasting on cognitive performance at rest and during exercise in adults. Sports Medicine, 46(1), 35–47.

de Azevedo, F. R., Ikeoka, D., & Caramelli, B. (2013). Effects of intermittent fasting on metabolism in men. Revista Da Associação Médica Brasileira (English Edition), 59(2), 167–173.

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

Photo by Brooke Lark on Unsplash

Posted 2 years ago by Aspen Streetman


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