We’re starting to understand why some people end up gaining back the weight they lost.

Obese people often lose weight but gain it back, but this may be partly due to permanent changes in the DNA within fat cells, a discovery that could one day lead to new treatments. may lead to.

Approximately 85% of overweight or obese people lose at least one-tenth of their body weight get it back within a year.

Part of the reason is that low-calorie diets are difficult to maintain over long periods of time, but that likely plays a relatively small role, he said. Laura Katarina Hinte at the Federal Institute of Technology Zurich, Switzerland. “There’s no way we all don’t have enough willpower to keep off the weight we lose.”

Research shows that the brain interprets a sudden drop in body fat as dangerous. It responds by reducing the body’s energy expenditure.

To learn more about this process, Hinte and his colleagues sampled adipose tissue from 20 obese patients, who were about to undergo bariatric surgery (a procedure that shrinks the stomach to help you feel full faster) and who had at least lost weight. It was analyzed two years later. 1/4 of the original weight. They also examined adipose tissue in 18 people with healthy weight.

Researchers have sequenced a type of genetic molecule called RNA that codes for proteins in fat cells. They found that obese people had increased or decreased levels of more than 100 RNA molecules compared to healthy weight people, and these differences persisted two years after weight loss.

These changes seem to exacerbate inflammation and disrupt the body’s state. Fat cells store and burn fat, both of which increase the risk of future weight gain, according to team members. Ferdinand von Mayenalso at the Federal Institute of Technology Zurich.

To examine whether these RNA changes could cause rebound weight gain, the researchers first determined that similar changes persisted even after obese mice lost weight. These mice, as well as mice of healthy weight, were then fed a high-fat diet for one month. The previously obese mice gained an average of 14 grams, while the other mice gained only 5 grams.

The researchers also found that fat cells from previously obese mice took up more fat and sugar than fat cells from other mice when cultured in a laboratory dish. Taken together, these results show how obesity-related RNA changes can increase future weight gain, von Mayen said.

Finally, the researchers found that molecular tags, or epigenetic marks, on the DNA of fat cells appear to drive RNA changes associated with obesity. They change RNA levels by changing the structure of the DNA that encodes it.

Although the study did not look for these molecular tags in the people studied or whether they regained the weight they lost, the findings likely apply from mice to humans. states. henriette kirchner At the University of Lübeck, Germany.

This is based on similarities between the physiology of these species and how the environment can change the way their genes work, known as epigenetics, she says. In the coming decades, Kirchner says drugs that target epigenetics could help treat obesity.