There appears to be a genetic explanation for yo-yo dieting, where people gain weight, go on a diet, and then put the pounds back on.
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According to new research published in the journal Nature, obesity can prompt fat cells to store “memories” of the body once being overweight.
The genetic change to the cells can help explain yo-yo dieting, says Ferdinand von Meyenn, professor of nutrition and metabolic epigenetics at the Federal Institute of Technology in Zurich, Switzerland.
“The fat cells remember the overweight state and can return to this state more easily,” von Meyenn said in a news release.
Researchers looked for molecular causes of the yo-yo effect in mice and noticed genetic changes to the rodents’ fat cells. When they were put on a diet, the mice lost weight. However, they regained it more quickly when put on a high-fat diet.
After analyzing fat tissue in humans who had the size of their stomachs reduced or gastric bypass surgeries, researchers noticed the samples had the same epigenetic — how cells control gene activity without changing the DNA sequence — markers in the nucleus.
“That means we’ve found a molecular basis for the yo-yo effect,” von Meyenn said.
One thing researchers haven’t investigated is how long fat cells can remember the body being obese.
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“Fat cells are long-lived cells,” said Laura Hinte, a doctoral student who took part in the research. “On average, they live for 10 years before our body replaces them with new cells.”
Hinte adds that there is no way to erase this memory from the cells.
“Maybe that’s something we’ll be able to do in the future,” said Hinte. “But for the time being, we have to live with this memory effect.”
To combat yo-yo dieting, von Meyenn said, there is only one way to avoid this weight cycling.
“It’s precisely because of this memory effect that it’s so important to avoid being overweight in the first place,” he said. “Because that’s the simplest way to combat the yo-yo phenomenon.”