ETH Zurich researchers have identified an “epigenetic memory” in fat cells that explains why lost weight often returns quickly after dieting. This biological basis for the frustrating “yo-yo effect” could lead to new approaches for maintaining weight loss.Published in Nature | Estimated reading time: 8 minutes
When people lose weight through dieting, they often regain it rapidly – a phenomenon known as the yo-yo effect that has puzzled scientists for years. Now, researchers at ETH Zurich have discovered that fat cells retain a lasting “memory” of their previous obese state, even after successful weight loss.
The research team found that obesity causes lasting chemical changes, called epigenetic modifications, to genes in fat cells. These modifications persist even after weight loss, making it easier for the cells to return to their previous state.
“The fat cells remember the overweight state and can return to this state more easily,” explains Professor Ferdinand von Meyenn, who led the study. “That means we’ve found a molecular basis for the yo-yo effect.”
The findings come from studies in both mice and humans. The researchers analyzed fat tissue from formerly overweight people who had undergone weight loss surgery, as well as from mice that were fed high-fat diets and then returned to normal diets.
“Fat cells are long-lived cells. On average, they live for ten years before our body replaces them with new cells,” explains Laura Hinte, the study’s lead author. This long lifespan means the epigenetic changes can persist for years.
Currently, there’s no way to erase this cellular memory with drugs. “Maybe that’s something we’ll be able to do in the future,” Hinte notes. “But for the time being, we have to live with this memory effect.”
The research emphasizes the importance of prevention. “It’s precisely because of this memory effect that it’s so important to avoid being overweight in the first place. Because that’s the simplest way to combat the yo-yo phenomenon,” says von Meyenn.
Glossary
- Epigenetics
- The study of biological mechanisms that switch genes on and off without changing the DNA sequence itself.
- Yo-yo Effect
- The cycle of losing weight through dieting, then regaining it quickly after the diet ends.
- Fat Cells (Adipocytes)
- Specialized cells that store energy as fat, playing a crucial role in body weight regulation.
Quiz
What causes the yo-yo effect according to the new research?
Answer: Epigenetic changes in fat cells that create a “memory” of the previous obese state, making it easier to regain weight.
How long do fat cells typically live?
Answer: About 10 years before being replaced by new cells.
Can the cellular memory of obesity currently be erased with drugs?
Answer: No, there are currently no drugs available to erase this epigenetic memory.
What is the main recommendation from researchers to avoid the yo-yo effect?
Answer: Prevention – avoiding becoming overweight in the first place, since the memory effect is difficult to counteract once established.
Enjoy this story? Subscribe to our newsletter at scienceblog.substack.com
