After successful weight loss, the risk of regaining the pounds is high. But why?
A recent study conducted by ETH Zurich has unveiled part of the mystery. Researchers have discovered that obesity causes lasting changes to the epigenome of fat cells. Unlike DNA, which remains unchanged, the epigenome records chemical modifications influenced by our lifestyle and eating habits.
These epigenetic markings act like a biological memory. When a fat cell experiences obesity, it retains this imprint even after weight loss. This memory then makes rapid weight regain more likely after dieting.
In mice, researchers identified these marks in adipocytes following weight loss. They observed that specimens that had lost weight regained fat much faster than those that had never been obese. This experiment suggests that these cells remain programmed to store fat excessively.
Analyses conducted on human samples confirm these findings. In collaboration with the Karolinska Institute and several European hospitals, researchers analyzed the tissues of patients who had undergone stomach reduction surgery. The epigenetic signatures found support the idea of a lasting memory of obesity in our cells.
This discovery disrupts our understanding of weight-gain mechanisms. Researchers emphasize that fat cells are probably not the only ones to retain this molecular memory. Other types of cells, especially in the brain or blood vessels, could also play a key role in the yo-yo effect.
For now, there is no method to erase this epigenetic memory. Fat cells, with their lifespan of nearly ten years, represent a significant challenge for researchers. However, these findings could pave the way for treatments targeting these molecular marks in the future.
In the meantime, preventing obesity from an early age remains the best approach. Understanding that this phenomenon is rooted in our biology also helps reduce the guilt often associated with the yo-yo effect. Researchers hope to encourage a more compassionate perspective on this issue.
What is the epigenetic memory of fat cells?
Epigenetic memory refers to the ability of fat cells to retain chemical modifications to their DNA without altering the genetic sequence itself. These marks influence gene expression, dictating their activation or inhibition.
In individuals who have been obese, these marks persist long after weight loss. They prompt cells to prioritize fat storage and limit fat burning, thereby increasing the likelihood of weight regain.
These marks, formed by influences such as diet and obesity, are stable but could potentially be altered by treatments in the future. Understanding them is essential for developing sustainable strategies to combat the yo-yo effect.
Article author: Cédric DEPOND