Scientists have explained why most people who lose weight gain it back on again over time
A study by American scientists has shown that as people develop obesity, their brains stop responding to satiety signals, which means that they start eating even more. Moreover, when the participants of the experiment lost weight, the brain's reaction to what they ate remained the same - the feeling of satiety did not return. That's why it is so difficult to lose weight - because of the confused settings of the feeling of satiety, they sooner or later start overeating again. About this with reference to the publication in the journal Nature Metabolism told the resource Everudauhealth.When a person eats, the gut normally transmits signals to the brain as nutrients from digested food arrive - a process that scientists believe may be crucial to regulating eating behavior. But a new study found that in obese people, the brain's ability to respond to these signals is significantly reduced.
Researchers used fMRI to monitor brain activity that signals satiety. The experiment tested how the brain responds to two types of nutrients - sugars and fats - in people with a body mass index (BMI) of 25 or less, which is a healthy weight, and in people with a BMI of 30 or higher, which is already considered obese.
The study found that in normal-weight people, eating sugar and fat led to decreased activity in several brain regions involved in regulating feelings of hunger. But the scientists found no brain response to these nutrients in obese people.
"This was surprising," the publication quoted the study's senior author, Dr. Mireille Cearley of the Yale School of Medicine in New Haven, Connecticut, as saying. - "We hypothesized that lean people and obese people would have different responses, but we didn't expect such a complete lack of change in brain activity in obese people.
Even after weight loss, the brain's satiety signals did not return.
To find out if it was possible to reverse this lack of brain response in obese people, the researchers asked obese participants to engage in a weight loss program for 12 weeks and then retested how the brain responded to what they ate. But even in the most weight-loss subgroup (participants who lost at least 10 percent of their weight), the brain's lack of response to sugar and fat remained consistent.
"These results suggest that changes in the brain's response to incoming nutrients in obese people may favor high-calorie intake that reintroduces obesity. Therefore, patients quickly regain weight after the weight loss they achieved with strict diets, " explained the authors of the study.