Does intermittent fasting work? a visual summary

Is intermittent fasting useful for weight loss? And to improve health indicators?

When trying to answer these types of questions by consulting the latest studies and reviews, things can become more complicated than expected. Intermittent fasting can be compared to not dieting or eating as usual (usual diet). Or also regarding specific eating patterns. Or diets with an equivalent continuous caloric restriction. In addition, there are various modalities of intermittent fasting and little standardization, the most popular being alternate day (ALT) and restricted hours (TRF).

In order to try to provide a global vision of the matter and thus complete the various posts that I have been publishing on the results of the studies, I have tried to visually represent a synthesis of the existing meta-analyses on intermittent fasting.

This is the result (click to enlarge):

I highlight the “I have tried” part, because things have not been easy at all. I have had to use quite a bit of imagination to integrate it all, given the variety of methodologies used by the different authors of each review. The reviews often mixed different types of intermittent fasting and different control diets, without making the conclusions very clear for each case (in those cases I have favored the more “conservative” result). So it should be considered simply an approximate and indicative graphic guide.

As you can see, I have represented the result for different indicators with different colors (weight, BMI, waist circumference, body fat, blood pressure, total cholesterol, LDL, HDL, triglycerides, glucose, insulin, insulin resistance and glycosylated hemoglobin). . Each color shows the result when intermittent fasting is compared to usual diet or continuous calorie restriction, as indicated by the legend below.

At a quick glance, it can be seen that intermittent fasting achieves quite positive results (green) in the left area of ​​the figure, that of the indicators associated with weight and anthropometric measurements. In the right zone, that of the cardiometabolic indicators, the results are more diverse.

For those who want to delve into the details, the meta-analyses included have been the following:

In any case, given the interest that this type of diet arouses, I am sure that this figure will lose its validity quickly. And let’s hope it’s because we reach more uniform and reliable conclusions.