The yo-yo effect of diets linked to epigenetic cellular memory

(Keystone-ATS) Anyone who has ever tried to get rid of a few extra pounds knows the frustration: the weight initially drops, then returns after a few weeks, the yoyo effect. Laura Hinte, a doctoral student in the group led by Ferdinand von Meyenn, professor of nutrition and metabolic epigenetics at ETH Zurich, was able to demonstrate that this phenomenon is due to epigenetics.

Epigenetics is the part of genetics which is based not on the sequence of genetic elements, but on chemical markers likely to be influenced by environmental factors, our eating habits or even the state of the body, such as obesity.

They can change over the course of life, but they can also remain stable for many years, sometimes decades. During this period, they play a key role in determining which genes are active in our cells and which are not.

An epigenetic memory of obesity

Scientists looked for the molecular causes of the yo-yo effect in mice. They analyzed fat cells from overweight mice and those who had lost excess weight through diet. Their research revealed that obesity leads to characteristic epigenetic changes in the nucleus of fat cells.

The particularity of these changes is that they persist even after a diet: “Adipose cells remember the state of overweight and can return to it more easily,” explains Professor von Meyenn, quoted in the press release.

The scientists were able to show that mice with these epigenetic markers regained weight more quickly when they again had access to a high-fat diet. They also found evidence of this mechanism in humans.

Long-lived cells

Adipose tissue biopsies from overweight people who underwent stomach reduction or gastric bypass surgery were analyzed. The results are consistent with those of mice.

Scientists have not yet studied how long fat cells can remember obesity. These are long-lived cells. “On average, they live ten years before our body replaces them,” notes Laura Hinte.

Furthermore, other body cells could also play a role in the yoyo effect, according to Professor von Meyenn. It is entirely conceivable that brain cells, blood vessels, or other organs contribute to the memory effect.

As it is currently impossible to modify these epigenetic markers in the cell nucleus, we have to live with this, the authors conclude. And first of all, avoid gaining weight.