Fat cells have memories. Not what we might consider memories, as such. But researchers say they’ve discovered fat cells ‘remember’ what it was like to be ‘fat’, and want to go there again. Which is why some of us ‘Yo-Yo’ when dieting…
The effect appears to be a combination of chemistry and epigenetics – the study of small yet char-acteristic chemical markers on our genes. Unlike the genes themselves. though, epigenetic markers, are more dynamic: environmental factors, our eating habits and conditions of our body – such as obesity – can change them over the course of the lifetime.
What happens
“Epigenetics tells a cell what kind of cell it is, and what it should do,” says Laura Hinte, a doctoral student in a team led by Ferdinand von Meyenn, Professor of Nutrition and Metabolic Epigenetics at the Federal Institute of Technology (FIT) in Zurich.
The team analysed fat cells from overweight mice and those that had shed excess weight through dieting. They found that obesity leads to characteristic epigenetic changes in the nucleus of fat cells – changes that they remain even after a diet. “The fat cells remember the overweight state and can return to this state more easily,” von Meyenn says.
Experiments showed that mice with these epigenetic markers regained weight more quickly when they were given access to a high-fat diet, again. “That means we’ve found a molecular basis for the yo-yo effect,” von Meyenn explains.
To cap off their findings, researchers also uncovered evidence for the same mechanism in humans.
Prevention is key
It’s not currently possible to change the relevant epigenetic markers in the cell nucleus with drugs, and effectively ‘erase’ unwanted epigenetic memories.
“Maybe that’s something we’ll be able to do in the future,” Hinte says. “But for the time being, we have to live with this memory effect.”
Von Meyenn adds: “It’s precisely because of this memory effect that it’s so important to avoid being overweight in the first place. Because that’s the simplest way to combat the yo-yo phenomenon.”
My take
So… The bad news is, it’s too late for those of us who have already been overweight or obese at some point in out lives. But the good news is, there may some day be a way to counteract the yo-yo effect by erasing the epigenetic markers that carry its memory.
Meanwhile, von Meyenn says, it’s ‘quite conceivable’ that cells in the brain, blood vessels or other organs also remember obesity, and contribute to the yo-yo effect. Whether this is actually the case is what the researchers want to find out next…