Why We're Fat
Gender and age matter more than you may realize
Women are also at a disadvantage after giving birth, says Wadden of the University of Pennsylvania, simply because they spend more time than men do around food. "[Women] tend to be grazers, and over the course of a day they can easily pick up an extra 500 calories." African-American women need to be particularly careful, notes a study in this week's Journal of the American College of Cardiology. Just the slightest weight gain, researchers found, puts them at higher risk of hypertension and heart failure.
Exercise can help, but here again women have a harder time than men. Tracy Horton, at the University of Colorado's Center for Human Nutrition, found that men and women use up fat at different rates during exercise. Women tend to burn relatively more fat. But in the hours after a workout, that may come back to haunt them, Horton says. Women's bodies can detect the fat deficit and so try to replenish fat stores as soon as possible by putting fat from meals right back on their thighs and hips. Men, on the other hand, burn more carbohydrates, so their bodies are more likely to hold on to new carbos and less likely to hang on to the fat. It may not be fair, but ultimately, women simply have to restrain their intake of food more than do men.
As if wrinkles and gray hair weren't enough, men and women in their 50s are more likely to be obese than at any other time of their lives. And where that fat sits on the body matters. The potbelly that men often grow in their middle years is not just unattractive, it's dangerous--considerably more so than the fat that women typically carry on their hips, thighs, and arms.
The midlife paunch, which doctors call "visceral fat," poses a risk because it surrounds the internal organs. It releases fatty acids that make their way into the liver, diminishing the organ's ability to process the hormone insulin, eventually causing diabetes. The fat also affects how the kidneys process insulin, a factor that scientists say may lead to high blood pressure. For every 10 percent increase over normal weight, men and women have about a 20 percent jump in risk for heart disease.
For women, these middle years can be a double whammy. In menopause, when women stop producing estrogen, gravity pulls down on hips, thighs, and buttocks, but abdominal fat often starts creeping upward. "This may be why, after menopause, the rate of heart disease in women equals that of men," says Aviva Must of Tufts University School of Medicine. Before that the rate of heart disease in women is significantly lower than that of men. Fortunately, hormone replacement therapy can minimize this abdominal weight gain.
As men and women reach their 60s and beyond, their body weight typically starts to decline. "As we get older we lose lean tissue, or muscle mass," Must says. "We have less body mass and less caloric need, so we gradually lose weight." Chronic diseases and medications can also interfere with appetite, as can depression and a diminished sense of taste. Weight-bearing exercises will help maintain muscle mass and keep the body strong. Weightlifting is especially important for women because it can stave off osteoporosis by maintain- ing bone density--and because women have less muscle to lose to begin with. "If a woman loses a significant portion of her muscle mass, she will be far weaker than a man who loses the same amount," Must says.
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