Fat cells remember obesity making weight loss harder to maintain, study finds

Many factors contribute to the frustrating cycle of weight gain and weight loss, but recent research suggests that fat cells may play a key role in this process. A study published in the journal Nature last fall found that fat cells have a memory of obesity, which can influence abnormal metabolic pathways in the body long after weight loss, making it easier for people to regain weight.

The study, conducted by a team of Swiss scientists, compared chemical markers on fat cells in mice who were fed a high-fat diet and then transitioned to a standard meal. The researchers found that even after losing weight, the mice who were previously obese continued to exhibit unhealthy changes in metabolism, such as difficulty in regulating sugar metabolism, inflammation, and abnormal fat storage. These mice also gained weight faster when reintroduced to a high-fat diet, indicating a continued impairment in metabolism after weight loss.

The study also analyzed human samples, looking at how genes in fat cells can lead to unhealthy changes in the body. Participants who underwent bariatric surgery showed that genes from fat cells continued to function abnormally two years after weight loss, leading to inflammation and metabolic problems. This suggests that fat cells retain a memory of obesity, which can impact weight management and overall health.

Gretchen Zimmermann, a registered dietitian and vice president of clinical strategy at Vida Health, confirms that fat cells indeed have a memory of being obese, making it easier to regain weight and maintain a state of inflammation and metabolic issues. However, she emphasizes that while biology plays a significant role in obesity, it is not the only factor at play. A combination of genetics, biology, environment, psychology, medications, and social determinants all contribute to obesity.

Zimmermann recommends maintaining healthy habits such as regular physical activity, a balanced diet rich in protein and fiber, and phytonutrients from plants to counteract the genetic factors that promote weight gain. Building muscle, reducing inflammation, improving blood sugar control, and supporting a healthy microbiome are essential for long-term weight management, even if weight loss is minimal.

Dr. Caroline Apovian, a professor of medicine at Harvard Medical School, points out that obesity is a chronic condition with an epigenetic cause, meaning that a person’s behaviors and environment can influence how genes work in the body. People who are genetically predisposed to storing calories may struggle more with weight loss and maintenance compared to others.

In conclusion, the study highlights the importance of understanding the role of fat cells in weight management and the challenges of maintaining weight loss. By adopting healthy habits and addressing genetic and environmental factors, individuals can better manage their weight and overall health.