For many people, losing weight is only part of the challenge—the real test often lies in keeping it off. A phenomenon commonly known as the “yo-yo effect” sees individuals regaining lost weight over time, frustrating their long-term health goals. While theories about decreased metabolic rates or behavioral changes have tried to explain this pattern, a groundbreaking study by researchers at ETH Zurich offers a new molecular insight: fat cells retain a “memory” of obesity, making sustained weight loss harder.
The Role of Epigenetics in Obesity’s “Memory”
Published in the prestigious journal Nature, the study reveals that fat cells undergo long-lasting epigenetic changes during obesity. Epigenetics involves modifications that affect how genes work without altering the DNA sequence, influenced by factors such as diet and environment. These changes appear to “lock in” the effects of obesity, impairing the normal functioning of fat cells even after significant weight loss.
“When a person is overweight, their fat cells develop epigenetic markers that persist even after weight loss,” explained Laura Hinte, co-author of the study. “This impacts how fat cells store energy and respond to dietary changes, keeping their behavior similar to their obese state.”
Key Findings from the Study
The researchers studied fat tissue from individuals who had undergone significant weight loss, such as gastric bypass surgery, and compared it to samples from obese participants. Their analysis revealed:
Even two years after weight loss, the fat cells of the participants behaved similarly to those of obese individuals.
In experiments on mice, researchers induced obesity with a high-fat diet, followed by a weight-loss phase using a standard diet. Despite losing weight, the mice's fat cells retained epigenetic markers of obesity.
When reintroduced to a high-fat diet, the mice regained weight more quickly and became obese more easily compared to mice without prior obesity.
“These findings highlight how fat cells ‘remember’ their past, making it easier to regain weight after weight loss,” said study co-author Professor Ferdinand von Meyenn.
Implications for Long-Term Weight Management
One striking conclusion of the study is the importance of preventing obesity in the first place. According to von Meyenn, fat cells can live for up to ten years before being replaced, allowing these epigenetic markers to persist over time.
“It’s precisely because of this memory effect that avoiding becoming overweight is so critical,” von Meyenn emphasized. “This is the most straightforward way to combat the yo-yo phenomenon.”
The study underscores the need for innovative strategies in obesity prevention and treatment. While traditional weight-loss methods like calorie restriction and exercise are important, they may not fully address the underlying cellular memory of obesity.
A Path Forward: Understanding and Addressing Obesity Memory
While the study provides compelling evidence of fat cells' memory, it also raises new questions: How long does this memory last? Can it be reversed? Further research could pave the way for therapies that target these epigenetic changes, potentially offering a more effective solution to combat obesity and the yo-yo effect.
For now, experts stress the importance of long-term lifestyle changes and early intervention to prevent obesity from taking hold.
Source: Euronews
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