A study by a team from the German Diabetes Research Centre shows that the brain's response to the hormone insulin adapts to short-term changes in diet even before weight gain occurs. As a result, this contributes to the development of obesity and other secondary diseases.
The findings are based on an experiment with 29 average-weight men. The first group followed a normal diet, while the second group was given an extra 1,500 calories to their usual diet. The extra calories came from processed and high-calorie snacks, such as chips and chocolate bars. The experiment was conducted for five days, after which the participants in the second group switched to a normal, balanced diet.
Before and after the experiment, all volunteers underwent MRI and laboratory tests. The results were disappointing. First, the second group showed a significant increase in liver fat. Second, the scientists recorded reduced insulin sensitivity - this effect persisted even a week after returning to normal nutrition.
"Previously, this effect was observed only in obese people. Now, for the first time, we see that even short negative changes in the diet of healthy people cause significant changes in the brain. Thus, the brain can contribute to the development of obesity, diabetes, and other diseases," the authors concluded.
In another study, scientists found that fat cells retain the memory of obesity for a long time. It turned out that they carry the memory of obesity even after dramatic weight loss and maintaining normal physical fitness for a long time.