I bet you’ve all heard the term ‘fasting’ thrown around lately, whether it’s word of mouth or online, it is really having a moment in the spotlight. Amongst personal endorsements and marketing promotions, it is good to know that there are many recent studies examining the evidence. However, fasting is not something new, in fact it’s been an integral part of human survival and evolution since the beginning of time. Over the past decade, however, an increase in studies have emerged supporting methods of fasting to reduce various metabolic markers of disease (Longo & Panda, 2016; Mattson, Longo, & Harvie, 2017). Some of these markers include:
- Significant weight loss, with large reductions to total fat mass.
- Reduced triglycerides, LDL and total cholesterol.
- Lowering inflammatory markers including IL-6, homocysteine, and CRP.
- Reducing the development of atherosclerotic plaque.
- Reduced heart rate and homocysteine levels.
- Reduction in glucose, insulin resistance and HbA1C.
So where did it all go wrong? In modern society, we can access food at any time, in any season or location, without even thinking twice about it! Factors such as advertising and marketing of food have seen industry tell us that we need to eat three main meals a day, and perhaps even snack in between. However, constant and convenient access to food has inadvertently led society towards patterns of overconsumption, drawing us away from the eating habits in which humans evolved and impacting on our health. Of course, fasting isn’t for everyone, just as frequent, regular meals aren’t for some. The point is that we are all different, and we need to consider each person’s individual needs and make up to find a dietary pattern that is most appropriate for them.
When it comes to fasting, there are several different methods to consider:
Intermittent: Comprises of extended periods (e.g. 16-48 hours) with little or no energy intake, intervening with normal periods of food intake.
Periodic: Refers to intermittent fasting periods or fasting mimicking diets for two to up to 21 days.
Time-restricted: Limiting daily food intake to 8 hours or less per day (Mattson, Longo, & Harvie, 2017). This method can trigger fasting physiological processes within only a few hours of feeding cessation without the need to reduce calorie intake (Longo & Panda, 2016, p.1048).
The great news is that according to the most recent studies, all of the above fasting methods increase longevity and lessen disease risk due to enhanced cellular and molecular processes. Such processes include the activation of adaptive cellular stress response signaling pathways, boosting DNA repair, autophagy and mitochondrial function (Mattson, Longo, & Harvie, 2017).
So who should practice fasting? First and foremost, although fasting has many benefits, there are also precautions to be aware of. For example, fasting is not recommended in pregnant or breastfeeding women, those under 18 or over 65 years of age, and those with certain health issues such as diabetes, hormone imbalances, and eating disorders, just to name a few. Therefore, it is highly recommended that individuals wanting to practice fasting seek guidance from a qualified health professional who can assess their health and advise them of the appropriate course of action (Malinowski et al. 2019).
Longo, V. D., & Panda, S. (2016). Fasting, Circadian Rhythms, and Time-Restricted Feeding in Healthy Lifespan. Cell Metabolism, 23(6), 1048–1059. http://doi.org/10.1016/j.cmet.2016.06.001
Malinowski, B., Zalewska, K., Węsierska, A., Sokołowska, M. M., Socha, M., Liczner, G., ... & Wiciński, M. (2019). Intermittent fasting in cardiovascular disorders—An overview. Nutrients, 11(3), 673.
Mattson, M. P., Longo, V. D., & Harvie, M. (2017). Impact of intermittent fasting on health and disease processes. Ageing Research Reviews, 39, 46–58. http://doi.org/10.1016/j.arr.2016.10.005