The Science Behind the Yo-Yo Effect: How Fat Cells “Remember” Obesity
Researchers at ETH Zurich have uncovered a key mechanism behind the frustrating yo-yo effect in weight loss: fat cells retain an “epigenetic memory” of obesity, making it easier to regain lost weight.
Why Dieting Often Fails in the Long Run
Anyone who has ever tried to lose weight knows the struggle—initial success is often followed by rapid weight regain. Scientists now reveal that this is due to epigenetics, a field of genetics that doesn’t rely on DNA sequences but rather on chemical markers that influence gene activity. These markers, shaped by environmental factors like diet and lifestyle, can persist for years and regulate how our cells behave.
Fat Cells Remember Obesity
The research team, led by Professor Ferdinand von Meyenn and doctoral student Laura Hinte, investigated this phenomenon in mice. They found that obesity causes lasting epigenetic changes in fat cells, even after weight loss. These changes make it easier for the body to regain weight when exposed to a high-fat diet. In essence, fat cells “remember” their previous overweight state and revert back to it more easily.
The team extended their study to humans by analyzing fat tissue samples from individuals who had undergone weight-loss surgeries like gastric bypass. Their findings aligned with the results in mice, confirming that fat cells in humans also exhibit this epigenetic memory.
Can We Erase This Memory?
Currently, there are no drugs capable of reversing these epigenetic marks. Fat cells are long-lived, surviving for about ten years before being replaced, meaning this memory effect can persist for a significant portion of a person’s life.
Given this, prevention becomes the best strategy. “Avoiding obesity in the first place is the most effective way to combat the yo-yo effect,” von Meyenn explains. This message is especially critical for children and young adults, whose lifelong metabolic health can be influenced by early weight gain.
The study also raises new questions: Could other cells in the body, such as those in the brain or blood vessels, also store an epigenetic memory of obesity? The researchers now aim to explore whether this hidden memory extends beyond fat cells, potentially offering new insights into long-term weight management.
