Very fashionable, intermittent fasting is not proven

Intermittent fasting is all the rage, and yet. According to a new randomized clinical trial of JAMAit would not be very effective in losing weight, and would even prevent the proper development of muscles.

Less 1.2 kilos in three months

To reach these conclusions, the team of scientists brought together 116 adults with a body mass index (BMI) between 27 and 43, and randomly divided them into two groups: the first participants ate three meals a day for three months, and the latter followed an intermittent diet over the same period. The intermittent fasting group could eat as they pleased between 12:00 p.m. and 8:00 p.m., but not outside these times. Both groups ate roughly the same number of calories per day.

At the end of the experiment, the researchers measured the weight loss of all the participants, as well as their fat mass and their lean mass. Conclusion: people who followed intermittent fasting lost just under 100 grams per week, or about 1.2 kilos in three months. In addition, they lost more muscle mass than the group following a classic diet of three meals a day.

“The loss of lean body mass is a worrying signal”

“Anyway you look at it, intermittent eating resulted in very modest weight loss,” said Ethan Weiss, co-author of the study. He adds : “Intermittent fasting offered no other metabolic benefit. In addition, the loss of lean mass is a worrying signal”. Note, however, that a period of three months is too short to sustainably lose a lot of weight.

In 2020, intermittent fasting has become one of the most followed diets in the United States, according to the International Food Information Council (IFIC). It also has many followers in France, especially among women.

Intermittent fasting is a term covering a family of diets consisting of alternating periods of fasting and periods of normal eating. Many temporal variations exist.