Belly Fat: Men's vs. Women's Risks
Men tend to collect more belly fat than women, and it starts early in life. "In adolescence and postadolescence, men start collecting abdominal fat," Kuller tells WebMD. "It's one of the reasons men have more coronary disease than women."
In one study, men with excess belly fat and a large waist were most at risk for what researchers call "all-cause mortality" -- early death from any cause. And because belly fat can trigger cardiovascular problems, a large belly has also been linked to erectile dysfunction in men over age 60.
Women tend to be protected before menopause, when their fat tends to collect on the buttocks and thighs. That type of fat may protect women from heart damage, research suggests. The below-the-waist fat cells are believed to produce a hormone that fights some of the heart-damaging effects of belly fat.
At menopause, however, women's fat tends to settle in the belly, most likely the effect of lower levels of estrogen, Kuller explains. That abdominal fat is much more dangerous than buttocks fat -- greatly increasing a woman's risk of death from heart disease, studies show.
- A woman is nearly five times more likely to die of heart disease if she has both a big waist and a high level of fats in her blood, according to one Danish study.
- Women are twice as likely to need gallstone surgery if they have a large waistline.
- Women may also have trouble getting pregnant if their belly is larger than their hips, a condition known as central obesity.
- Women are at one-third higher risk of breast cancer if they have excess belly fat, one study shows. In fact, several types of cancer -- breast cancer, uterine, cervix, colon, kidney, and pancreas -- have been linked with obesity.
Here's what happens: As fat cells break down, chemicals released "act as very powerful cell-proliferating agents," Kuller tells WebMD. "This may be why obesity is a risk factor for various cancers... because it stimulates cancer cells to proliferate more rapidly."
Kuller believes that breast cancer risk is due more to a woman's overall body fat -- not just belly fat.
"There is substantial evidence that body fat causes the body to produce more estrogen than necessary," Kuller says. "Obesity is probably the No. 1 risk factor for postmenopausal breast cancer, especially estrogen-receptor-positive breast cancer."