A recent study found that women with a body mass index (BMI) of 25 to 29.9 considered overweight by the National Institutes of Health had a 23 percent lower risk of dying from any cause within 12 years than women who had "normal" BMIs. Why? "Combined with regular exercise and eating right, being a little overweight may help protect the body as we age," says study coauthor Mark Kaplan, Dr.P.H. Women who don't sweat their curves may remain worry-free, and "lower stress levels and a healthy lifestyle can add up to longer life," he says. Want to dance at your 100th birthday party? Focus less on getting slim and more on being strong.