New study explains why yo-yo dieting is so common

Your friends and family will likely applaud your significant weight loss—but your cells may be resisting the changes.

New research reveals that obesity can cause genetic modifications within fat cells that allow the cells to store “memories” of being overweight in their core and make it easier for the body to put the pounds back on.

“We have found a molecular basis for the yo-yo effect,” said Ferdinand von Meyenn, professor of nutrition and metabolic epigenetics at ETH University Zurich in Switzerland.

Yo-yo dieting—a continuous pattern of weight loss and gain—is common in American culture thanks to the popularity of fad diets and quick fixes for weight loss.

When examining mice, ETH Zurich researchers noticed that obesity causes genetic changes in the nucleus of fat cells that remain even after weight loss through diet.

They confirmed these changes in humans by analyzing adipose tissue from people who had undergone gastric reduction or gastric bypass procedures.

Their findings were published Monday in the journal Nature.

What is unclear from the new study is how long fat cells can remember obesity.

“Fat cells are long-lived cells. On average, they live for 10 years before our body replaces them with new cells,” said Laura Hinte, a PhD student in von Meyenn’s group.

It is also unknown whether other cells, such as those in the brain, blood vessels and other organs, can remember obesity.

“Other cells in the body may also play a role in the yo-yo effect,” von Meyenn said.

Unfortunately, the researchers say that drugs cannot reverse the modifications inside the cell nucleus and erase the “memory” of obesity.

“Maybe that’s something we’ll be able to do in the future,” Hinte said. “But for now, we have to live with this memory effect.”

Von Meyenn added: “It is precisely because of this memory effect that it is so important to avoid obesity in the first place. Because that’s the easiest way to fight the yo-yo phenomenon.”

His advice comes as the obesity epidemic continues to grow — research finds that more than 40% of US adults and nearly 20% of American children are obese.

Being overweight or obese significantly increases the risk of more than a dozen types of cancer, including breast, colon, kidney, liver, pancreatic and ovarian cancer.

It also increases the chances of developing heart disease, type 2 diabetes, high cholesterol, breathing problems, joint problems and depression.