Intermittent fasting has gained extreme relevance in recent years, both among people who tested and “discovered” the Holy Grail of diets, and among nutritionists and other professionals linked to the science of weight loss.
But what does science tell us?
Science is quite pragmatic and showed us that fasting did not always lead to weight loss, and it even increased in one of the cases studied. In most cases and studies, it was not clear whether the positive results were due to fasting or just the induced energy deficit. What is important to remember, and what science reinforces, is that intermittent fasting results in the same way as energy deficit (energy expenditure greater than the total energy consumed), when the objective is to lose weight.
Does intermittent fasting work or not?
Without a doubt, intermittent fasting can work if the result is an energy deficit, leading to weight loss. Something that we must take into account when opting for such a “severe” strategy as narrowing the window in which we eat food, is also the social aspect. And we cannot forget that food is much more than calories and macronutrients, but family, social life and pleasure.
If for someone, doing intermittent fasting is something that does not require any sacrifice, or even fits into their work schedule, and this leads to an energy deficit, intermittent fasting will undoubtedly be a very valid option. However, if for someone else this means having to make a big sacrifice, this option should be discarded, because as science reports, intermittent fasting results in the same way as energy deficit when we talk about weight loss.
In short, we should look at intermittent fasting as an option for weight loss, but not as the cure for all diseases and the 'Holy Grail' of diets. Even more important, we must be careful and know how to filter what we read and hear on the internet, whether on websites, blogs or social networks, as many professionals try to sell their ideas and defend them to the end, leaving science aside.
Rui Jorge Lopes
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Intermittent fasting: What questions should we be asking? Physiol Behav [Internet]. 2020;218(December 2019): 112827. Available from: https://doi.org/10.1016/j.physbeh.2020.112827