How To Avoid The Yo-Yo Effect
A new study published in Nature shows that intestinal bacteria play an important role in weight gain following a period of slimming, commonly known as the “yo-yo effect”. And this phenomenon could be avoided thanks to supplementation in flavonoids.
After a diet, many people have to deal with a phenomenon called “yo-yo effect” which results in a recovery of lost weight or even more, within 12 months after weight loss. And this effect is accentuated with each new diet. With each cycle of weight loss and weight gain, the proportion of body fat increases, as well as the risk of developing a metabolic syndrome (diabetes, fatty liver or other obesity related disorders). More and more studies suggest the role of an imbalance of the intestinal microbiota (dysbiosis) in the development of obesity. Dietary changes play a central role in the composition and function of the intestinal microbiota. The intestinal microbiota of obese people is different from that of people of normal corpulence.
In this study, the researchers carried out a series of experiments on mice to mimic cycles of weight loss and weight gain in order to determine the mechanisms explaining the yo-yo effect. They noticed that after a cycle of gain and then weight loss, all the body systems of the mouse returned to normal except the intestinal microbiota: about 6 months after weight loss, the mice retained an abnormal intestinal microbiota of Obese mouse.
” We have shown in obese mice that after a successful diet and therefore weight loss, the intestinal microbiota keeps a memory of the previous obesity, ” the researchers said. ” And the persistence of this obese mouse microbiota accelerates the recovery of weight when mice return to a high calorie diet or eat too much .”
However, researchers have developed therapeutic approaches to mitigate the impact of the intestinal microbiota on weight gain. For example, by depleting intestinal bacteria in mice by administering a broad-spectrum antibiotic, they did not observe excessive weight gain after dieting. In another experiment, the researchers introduced intestinal bacteria from mice with a history of obesity in mice without microbiota. They then observed that these mice had accelerated weight gain when consuming a high calorie diet (which promotes overweight and obesity), compared to mice receiving intestinal bacteria from other mice without a history of obesity . But by implanting to previously obese mice, intestinal bacteria from mice that have never been, researchers have managed to erase this memory of obesity and prevent excessive weight gain upon a return to a rich diet in calories.
Scientists have also identified two molecules that play a role in the impact of the intestinal microbiota on weight recovery. These molecules belong to the family of flavonoids. In obese mice, after the diet, the intestinal microbiota rapidly degrades these flavonoids so that the level of these molecules is significantly lower than in mice without a history of obesity. However, the researchers found that under normal circumstances, these two flavonoids promote energy expenditure in the metabolism of fats. The fact that they are present in smaller amounts leads to an accumulation of extra fats when the mice return to a more caloric diet.
The researchers also tried to supplement mice with flavonoids after dieting. This made it possible to reduce their level of flavonoids to normal and thus their energy expenditure. This supplementation prevented excessive weight gain in the post-diet period. This strategy could prevent the yo-yo effect after dieting.
Christoph A. Thaiss, Shlomik Itav, Daphna Rothschild, Mariska Meijer, Maayan Levy, Claudia Moresi, Lenka Dohnalová, Sofia Braverman, Shachar Rozin, Sergey Malitsky, Mally Dori-Bachash, Yael Kuperman, Inbal Biton, Arieh Gertler, Alon Harmelin, Hagit Shapiro, Zamir Halpern, Asaph Aharoni, Eran Segal, Eran Elinav. Persistent microbiome alterations modulate the rate of post-dieting weight regain. Nature, 2016; DOI: 10.1038/nature20796