Nena Rokx
The last couple of months, social media platforms have been focusing on a new type of lifestyle for losing weight and improving overall health: intermittent fasting. Most of the hype has been about the 16/8 method. This method affects the hours of food intake, which is restricted to 8 hours a day. Another popular method of intermittent fasting includes complete fasting for a minimum of one day a week. If desired, you are allowed to eat one meal of a maximum of 25% of your caloric need on a fasting day [1,2]. In general, intermittent fasting should be followed 2-3 times a year for a period of 6-8 weeks [1]. This made us wonder whether intermittent fasting could really improve your overall health and help to lose weight.
The idea of intermittent fasting is based on the fact that there were periods of food scarcity during the evolution. However, since world war II, food has been in abundance in western countries. Furthermore, in the last decades, the incidence of overweight and western diseases, like diabetes and cardiovascular disease, has increased massively. Possibly, there is a link between both of these events [1,2]. When fasting intermittently, you simulate a period of food scarcity which may contribute to reducing disease risks for obesity, cardiovascular disease, type 2 diabetes and possibly also neurodegenerative disorders. The possible underlying cellular and molecular mechanisms involve activation of adaptive cellular stress response signalling pathways that enhance mitochondrial health, DNA repair and autophagy [2].
For some people, intermittent fasting will result in weight loss which may have two causes. First, because you only eat during the feeding window your overall calorie intake may be lower. Secondly, by fasting you prolong the period of fat burning. After about 10-12 hours of fasting your body turns from sugar to fat burning. Normally, your overnight fast will be about 8-12 hours but following intermittent fasting this period will be prolonged with 4-6 hours. Therefore, you will also prolong the period of fat burning which may result in weight loss [1].
However, the number of studies on intermittent fasting is relatively small and most of the research is performed in animals. Therefore, in spite of the promising results, more research should be done on the effects of intermittent fasting on humans, before it can seen as a wonder diet.
[1] Ludidi, S. De kracht van onderbroken vasten. OrthoFyto 4/2019, 12-17 (2019).
[2] Mattson, M.P., Longo, V.D., Harvie, M. Impact of intermittent fasting on health and disease processes. Ageing Research Reviews 39, 46-58 (2017).