Why do you put on weight when you hit middle-age?

Wonder why you've started to put on weight despite eating and exercising the same as always? Scientists from Karolinska Institutet, Sweden, discover the reason lies in the decline of your lipid turnover…

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Middle-age spread is a problem for many, even those exercising and eating the same as always. But now scientists from Karolinska Institutet in Sweden have discovered that this is due to your lipid turnover in the fat tissue decreasing as you age. Lipid turnover is the the rate at which lipid (or fat) in fat cells is removed and stored, so basically the body becomes less efficient at processing fat. 


For 13 years, scientists monitored the weight and lipid turnover of 54 men and women, and found all subjects, regardless of whether they gained or lost weight, showed decreases in lipid turnover. Those who didn’t compensate for that by eating less calories gained weight by an average of 20%, according to the study which was done in collaboration with researchers at Uppsala University in Sweden and University of Lyon in France.

“The results indicate for the first time that processes in our fat tissue regulate changes in body weight during ageing in a way that is independent of other factors,” says Peter Arner, professor at the Department of Medicine in Huddinge at Karolinska Institutet and one of the study’s co- authors. “This could open up new ways to treat obesity.”

Previously, science has highlighted one way of speeding up the lipid turnover in the fat tissue is to exercise more, and this new research supports that notion. 

“Obesity and obesity-related diseases have become a global problem,” says Kirsty Spalding, senior researcher at the Department of Cell and Molecular Biology at Karolinska Institutet and another of the study’s co-authors. “Understanding lipid dynamics and what regulates the size of the fat mass in humans has never been more relevant.”


The research was published in www.nature.com