Why of those who have already followed a low-calorie diet in order to lose weight have already experienced the yo-yo effect: a recovery of the pounds lost as soon as the diet is stoppeddue to a greater feeling of hunger.

Researchers from the Max Planck Institute for Metabolism Research (Cologne, Germany) and Harvard Medical School (Boston, USA) report observing what happens in the brain when dieting. The yo-yo effect would come from the fact that the nerve cells which play the role of mediator of the hunger pangs receive stronger signals when dieting, so that we want to eat more as soon as it ends.

“ People have mainly studied the short-term effects after dieting. We wanted to see what changes occur in the brain over the long term “, explained Dr. Henning Fenselau, researcher at the Max Planck Institute and co-author of the study, in a press release (source 2).

To do this, the researchers put laboratory mice on a diet and then assessed any visible changes in the brain circuits. In particular, they observed a group of neurons, AgRP neurons, known to control feelings of hunger. They then found that the neural pathways stimulating these neurons sent increased signals when the mice were on a diet, and that this change was present long after the diet.

In a second step, the research team succeeded in inhibiting the neural pathways activating the AgRP neurons, so that the mice had a lesser “yo-yo effect” after the diet. “ In the long term, our goal is to find therapies for humans that could help maintain weight loss after dieting. To achieve this, we continue to explore how we might block the mechanisms that mediate the strengthening of neural pathways in humans. concluded Dr. Fenselau.