Losing weight can be difficult
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people who obesity those who lose weight often put it back on, which may be due in part to permanent changes in the DNA of their fat cells, a discovery that could one day lead to new treatments.
About 85 percent of people who are overweight or obese lose a tenth of their body weight. recovered in.
That’s partly because it’s hard to stick to low-calorie diets for long, though that probably plays a relatively small role, he says. Laura Catharina Hinte at the Federal Institute of Technology in Zurich, Switzerland. “It’s impossible for all of us to lack the willpower to maintain the weight we’ve lost.”
Research has also shown that the brain perceives a significant decrease in body fat as dangerous the body responds by burning less energy.
To learn more about this process, Hinte and his colleagues analyzed adipose tissue taken from 20 obese people before they had bariatric surgery, which shrinks the stomach to make people feel fuller sooner, and again two years later when they had lost at least the weight. a quarter of the initial body weight. They also analyzed the fat tissue of 18 healthy weight people.
The researchers sequenced a type of genetic molecule called RNAwhich encodes proteins in fat cells. They found that obese people had increased or decreased levels of more than 100 RNA molecules compared to people of a healthy weight, and these differences persisted two years after weight loss.
These changes seem to increase inflammation and disrupt how it works fat cells store and burn fat, both of which increase the risk of future weight gain, the team says Ferdinand von MeyenneAlso at the Federal Institute of Technology in Zurich.
To examine whether these RNA changes could cause rebound weight, the researchers first confirmed that similar changes persisted after the obese mice lost weight. These healthy-weight mice and rats were then fed a high-fat diet for a month. While the previously obese mice gained 14 grams of weight, on average, the other mice gained just 5 grams.
The team also found that fat cells from previously obese mice took up more fat and sugar when grown in a lab dish than other mice. Together, the results show how obesity-related RNA changes can increase future weight, says von Meyenne.
Finally, the team found that molecular tags, or epigenetic marks, in the DNA of fat cells drove obesity-related RNA changes. These change the level of RNA, changing the structure of the DNA that encodes it.
Although the study did not look for these molecular markers in the people they studied, or whether they regained the weight they lost, he says the findings likely translate from mice to humans. Henriette Kirchner at the University of Lübeck in Germany.
It is based on the similarities between the physiology of these species and how the environment can change the way their genes work, ie. epigeneticshe says In the coming decades, drugs that target epigenetics may help treat obesity, Kirchner says.
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