The trend has been on the rise for a few years now: the diet or intermittent fasting brings together various practices with a common point, that ofalternate periods of more or less long food restrictions – sometimes going for a whole day – with periods when it is possible to eat normally.
It is often presented as THE most effective diet, but is it really the case? If some believe that it avoids the frustrations linked to a continuous restriction of food or that it has many benefits on metabolic parameters such as blood pressure, blood sugar or cholesterol and would prevent certain diseases (cancers, inflammatory diseases… ), however, studies are lacking to properly assess these diets. The heterogeneity of practices also complicates the generalization of the benefits or otherwise of a single form of fasting to all so-called “intermittent” diets, indicates theInserm.
What are the three most common intermittent diets?
- THE 5:2 dietwhich consists of eating normally for 5 days and then significantly reducing the number of calories in the following two days;
- THE 16/8 regimewhich consists of fasting for a period of 14 to 16 hours during the day and eating meals for the following 8 to 10 hours;
- I’alternate day fastingwhich consists of fasting every other day.
What do these diets promise? The objective of intermittent diets is relatively simple: to facilitate weight loss, while limiting the constraints associated with other restrictive diets. However, according to Inserm, most scientific publications do not show any superiority of these intermittent diets in terms of weight loss.
For its analysis, the National Institute of Health and Medical Research focuses on several studies dealing mainly with the 5:2 diet. A first, published in 2018 in theInternational Journal of Obesity was conducted among 332 people with obesity divided into three groups (continuous restriction, alternating restriction every other week and intermittent restriction 5:2). Only 146 patients completed the study, with similar weight loss in the three groups (6.6 kg, 5.1 kg and 5 kg on average). Another, also published in 2018 in Tea American Journal of Clinical Nutrition wanted to compare the 5:2 diet and the continuous restriction diet to a “normal” diet without any restrictions in obese subjects as well. If the first two groups are indeed those who lost the most weight, no metabolic difference was found between the two restriction groups.
If they do not seem less effective for weight loss, this are not “miracle diets”. Inserm calls for other factors to be taken into account, in particular the impact that these diets can have on appetite or even on the balance of eating behavior. “As for the question of whether people who practice an intermittent diet ‘overcompensate’ by eating more in the periods when this is allowed to them, it is not yet fully settled”, concludes Inserm.
Source :
- Intermittent diets, more effective for weight loss, really?, Inserm, October 7, 2022
