Fat Cells Remember Being Fat, New Yo-Yo Diet Study Explains

If you've gained back fat after losing weight, you aren't alone. And, as it turns out, yo-yo dieting might not be the direct cause of the sudden fluctuation in fat distribution. 

A new study published by scientists at ETH Zurich explains that fat cells "store memories of obesity in their cell nucleus," according to a statement from the Swiss university. As a result, the cells retain these memories even after you lose weight, making you more susceptible to future weight gain. 

It all has to do, they say, with the epigenetics of fat cells. "Epigenetics tells a cell what kind of cell it is and what it should do," researcher Laura Hinte said in a statement. To reach their conclusion, they analyzed fat cells from overweight mice and those that lost weight through dieting. What they found was that obesity leads to epigenetic changes in the nucleus of fat cells as the mice who lost weight regained it more quickly when they were reintroduced to a high-fat diet. 

"The fat cells remember the overweight state and can return to this state more easily," study leader Ferdinand von Meyenn explained. "That means we’ve found a molecular basis for the yo-yo effect."

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Science hasn't advanced enough for us to change epigenetic marks in cells with drugs, so it isn't possible just yet to wipe the so-called memory of your fat cells. "Maybe that’s something we’ll be able to do in the future," Hinte mused. "But for the time being, we have to live with this memory effect." 

It's a groundbreaking find, and it raises more questions about cell behavior throughout the entire body. The team, for example, doesn't believe that this "memory" is limited to just fat cells. "Other body cells might also play a part in the yo-yo effect," von Meyenn said. 

For now, the best strategy to avoid altering your cells in this way is to avoid getting up there at all. 

"It’s precisely because of this memory effect that it’s so important to avoid being overweight in the first place," von Meyenn concluded. "That’s the simplest way to combat the yo-yo phenomenon."