Belly Fat: Why Men and Women Store Fat Differently

Belly fat tends to affect men more than women, who generally get wider in the hips when they gain weight. Now, a new study reveals the reason why.

The reason why men store fat in their midsection and women pack on the pounds in their hips may finally be clear. The fat tissue in women and men is almost completely different, according to a new study.

Researchers examined the genetic makeup of mice, because mice distribute fat in patterns similar to humans. The study showed that of about 40,000 mouse genes, only 138 are found in both male and female fat genes – a fact that came as a surprise to the researchers.

“We expected the exact opposite — that 138 would be different and the rest would be the same between the sexes,” said Dr. Deborah Clegg, senior author of the study and assistant professor of internal medicine at UT Southwestern Medical Center.

The study also found that male mice that were put on a diet high in fat gained more weight and had more highly inflamed tissue, especially belly fat, than the female mice that were put on the same diet.

However, when the female mice had their ovaries removed, which is similar to a woman going through menopause, they had a higher weight gain, and the additional body mass was more likely to result in belly fat.

Researchers admit that the new findings don’t explain why women start storing fat in their midsection after menopause, but the results do indicate that hormones produced by the ovaries play an important role in the tendency for women to gain unwanted belly fat in middle age. Understanding this connection could lead to new innovations in hormone replacement therapy.

The full study appears in the current issue of the International Journal of Obesity.