Fat cells have a “memory” of obesity, which may help explain why it’s so difficult to maintain weight loss, according to a new study published Monday in the journal Nature.
Individuals who have lost weight often later gain the weight back, in a phenomenon known as the “yo-yo effect.” Now, the new research suggests changes at the cellular level may be partially responsible for the body’s tendency to revert to obesity after weight loss.
Obesity leads to epigenetic changes, or chemical alterations to DNA that affect gene activity. The new paper suggests that in fat cells, these changes linger even after a person loses weight. And the cells, beyond simply “remembering” their prior state of obesity, “likely aim to return to this state,” says study co-author Ferdinand von Meyenn, an epigeneticist at ETH Zürich, to the Guardian’s Ian Sample.
Scientists studied body fat, also known as adipose tissue, from two groups of participants: One group had never been obese, while the other group had experienced severe obesity. When the researchers compared fat cells between the two groups, they found differences in gene activity.
Certain genes in the fat cells of participants with obesity were more active, and others were less active, compared to the control group, reports Nature News’ Traci Watson. The genes that were more active play a role in the formation of thick, scar-like tissue (called fibrosis), as well as inflammation. The genes that were less active are responsible for helping the fat cells function normally.
These gene activity patterns remained constant, even after the individuals with severe obesity had undergone weight-loss surgeries. Though the participants had lost weight, the genes in their fat cells still behaved as if they were obese.
Scientists are also not sure whether the obesity-linked epigenetic changes are permanent. And, if these DNA changes are reversible, researchers don’t know how long they last. But the findings suggest preventing obesity in the first place is likely easier than trying to lose weight and keep it off.
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By Sarah Kuta / Courtesy of The Smithsonian Institute
