Dec 03, 2024 08:00:00

The possibility that the 'memory of when you were obese' that fat cells have may be the cause of rebound

Many people have experienced losing motivation to diet after a while because they rebounded after dieting. A new study suggests that fat cells retain 'memory' of their obese state even after they lose weight, which may be the cause of rebound.

Adipose tissue retains an epigenetic memory of obesity after weight loss | Nature

https://www.nature.com/articles/s41586-024-08165-7

Fat cells have a 'memory' of obesity, study finds | Live Science
https://www.livescience.com/health/fat-cells-have-a-memory-of-obesity-study-finds

People who end up regaining the weight they lost after dieting may be told that they 'didn't have enough willpower' or that they let their guard down after losing weight, but recent research suggests that biological factors beyond the individual's efforts may also be involved in the rebound.

To understand the molecular mechanisms behind rebound, a new research team from ETH Zurich and the University of Leipzig has studied epigenetics in the DNA of mice and humans.

Epigenetics is a mechanism by which the function of genes is controlled by modifications made to DNA later, without changing the base sequence of DNA. The main processes that control epigenetics are DNA methylation and histone modification , and these processes change the function of cells even though they have the same DNA.

In a study, mice were put on a high-fat diet to gain weight, then allowed to lose weight back to normal. Although these dieting mice were metabolically no different from mice that had never been fed a high-fat diet, their fat cells still retained the epigenetic changes that had occurred during weight gain.

'We know that fat cells undergo a kind of identity crisis when they become obese. They forget who they are and what they're supposed to do,' said Laura Hinte, lead author of the study and a doctoral student at ETH Zurich. 'These changes suggest that these changes continue even after weight loss.'

Next, when they exposed fat cells from formerly obese mice and never-obese mice to

glucose and palmitate , they found that the obese mice took up more glucose and palmitate than the non-obese mice.

'The epigenetic changes had no effect on the mice when they were in a healthy environment,' said Hinte.

Although this study did not prove that epigenetic changes in obesity cells directly cause rebound, it suggested that some mechanism may be involved in this. It is also possible that obesity 'memory' remains in neurons and other cells, just like fat cells, and that this may affect other obesity factors such as appetite.