The Belly Burden
Forget the scale. New research points to waistline size as a better predictor of health
The connection between fat distribution and sex hormones is only now being explored. The apple shape "tends to be associated with higher male hormone levels in women, and this may be one of the reasons that men and women tend to have a different body fat distribution," says Manson. Men, who naturally have more male hormones than women, also accumulate fat around their waists more frequently than women. Though the role hormones play in fat distribution is not yet clear, the way many women lose their waist at menopause may be due to changes in the relative levels of androgen to estrogen. Clinical trials of hormone replacement therapy, however, did not show that postmenopausal women who took the drugs had a substantial waist-size reduction, says Manson.
Apple vs. pear. Conversely, the pear shape or the hourglass figure may be linked to higher estrogen levels and greater fertility. One study of Polish women indicated that those with large breasts, small waists, and wide hips had higher levels of estrogen than those who were more apple shaped. "It's possible that it's a fat distribution pattern [hourglass] associated with the higher likelihood of reproductive success, and it was something that was selected for" during women's evolution, says Manson.
Some recent studies also indicate that hip and thigh fat--common to pear-shaped people--may actually offer some unique safeguard against cardiovascular disease. "Hip fat is definitely protective," says Marie Savard, a Philadelphia internist who is researching the health effects of body shape. She points to a 2004 Danish study of nearly 3,000 men and women that showed that a larger hip circumference reduced cardiovascular disease and death among women but had no positive effect for men. Similarly, research on 3,000 older adults reported in the Archives of Internal Medicine earlier this year confirmed not only that abdominal fat leads to metabolic syndrome but also that leg and thigh fat--among both women and men--was associated with a lower prevalence of metabolic syndrome and less heart disease.
But not all researchers agree that hip fat is beneficial, and if it is, no one yet knows why. One theory is that hip and thigh fat may act as a metabolic reservoir, storing harmful blood fats that would otherwise circulate throughout the body. Or it could be that fat on the hips, thighs, and legs may just indicate that a person is genetically pear shaped and less inclined to gain the spare tire that plagues the more apple shaped. Still, more lower-body fat generally means more fat--period--which clearly leads to higher risk of heart disease and diabetes.
It will be decades before medicine unravels the metabolic puzzle that is fat. In the meantime, doctors say the important action to take is to stop waist expansion. "We all need to slow down this process of becoming more applelike," says Savard. "Body shape really does matter."
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