Keeping weight off may be stymied by fat cells’ ‘memory’ of obesity

Fat tissue may commit weight to memory.

For folk living with obesity, shedding pounds might help reduce the chance of health problems reminiscent of type 2 diabetes or heart problems (SN: 2/29/24). But shedding pounds and keeping it off is challenging, and it’s unclear why. A new study in mice and human cells shows that the struggle may in part be on account of genetic changes which is able to persist even after weight reduction.

Chemical tags on DNA that act as genetic switchboards, often sometimes called epigenetics, can regulate which genes are turned on or off (SN: 2/18/15). In fat tissue, the status of some genes and these tags appear to create a cellular “memory” of obesity, researchers report November 18 in Nature. That memory may suppress metabolism and speed nutrient intake, making it challenging for weight reduction efforts to stick, the findings suggest.

The findings point toward a explanation for the “yo-yo” cycle, at some stage in which people over and over lose and regain weight, says Ferdinand von Meyenn, an epigeneticist at ETH Zurich. “How will we give a boost to that? How will we alter that? Because otherwise [the genetic changes] could be there and people will have a challenging time getting over that,” he says.

Von Meyenn and colleagues when put next adipose tissue — which contains fat cells and other sorts of cells — from people with and without obesity. Genes linked to metabolism were less active in tissue from people with obesity, even after those people lost weight.

Experiments in mice also showed that some genes desirous about metabolism were still turned off in formerly obese animals. Many of those genes were linked to epigenetic changes which may influence how DNA gets switched on or off, von Meyenn says.

What’s more, fat cells from formerly obese mice take in nutrients a extremely good deal faster than cells from lean mice, the team found. After the mice lost weight, animals with obesity memory were faster to gain weight.

While shedding pounds can give a boost to metabolic health, the epigenetic changes that stick around suggest that for some people, keeping it off is an uphill battle, von Meyenn says. People taking weight reduction and diabetes drugs like Ozempic may regain weight if they stop treatment, hinting that the medication don’t adjust the genetic changes (SN: 12/13/23). But possibly other drugs or a mix of treatments could one day wipe fat cells’ memories.