Keeping weight off after significant weight loss can be a frustrating and challenging task for many people, Deutsche Welle reports.
New research suggests that one of the reasons this is so difficult may lie in the “memory” of fat cells, which appear to retain a record of past obesity, making it easier to regain weight even after successful dieting and exercise.
A recent study published in Nature reveals that fat cells do not simply increase in number when a person gains weight, but instead change the way they store nutrients. This “fat cell memory” could persist for years, even after a person has lost weight, making them more susceptible to regaining lost pounds.
Researchers at the University of Zurich’s Institute of Food, Nutrition, and Health found that the key to understanding this phenomenon lies in epigenetic changes within fat cells. Epigenetic changes refer to modifications in gene expression that occur due to environmental factors, meaning that weight gain can have lasting effects on our cells, even if the tendency toward obesity is not inherited.
The team investigated fat tissue from individuals who had undergone weight loss surgery, comparing it to tissue from people without a history of obesity. They discovered that certain genes were more active in the fat cells of those who had been obese, and these genetic changes persisted long after the weight loss. This molecular memory is what makes it harder to maintain a healthy weight once it’s been lost.
In animal models, particularly mice, the researchers observed that fat cells in those that had been obese responded more aggressively to high-calorie diets. These cells took up more nutrients and grew larger more quickly than those of mice that had never been obese. This phenomenon also appeared to occur in humans, suggesting that the “memory” of obesity in fat cells may prime the body to regain weight faster after dieting.
In addition to the changes in fat cells, the researchers speculated that other factors throughout the body, such as the brain, could contribute to the challenges of weight maintenance. Evolutionarily, the human body is adapted to resist weight loss, as periods of food scarcity were common throughout history. This could explain why the body works so hard to defend its fat stores, especially after weight loss.
While the epigenetic changes in fat cells appear to be significant, it is still unclear how long these memories persist. The study found that these changes remained evident in both humans and mice over a period of two years and eight weeks, respectively. Fat cells can live for up to 10 years, so it’s possible that the “memory” of obesity could last for many years.
For now, there are no pharmacological treatments available to erase this fat cell memory. However, researchers are hopeful that with further investigation, it may become possible to reprogram fat cells or develop treatments to help prevent weight regain. Some experts believe that maintaining a healthy weight over a long period of time could potentially help reverse this memory, but more research is needed to confirm this.
