Hugh Pickens writes "Findings of a new study show that underweight people and those who are extremely obese die earlier than people of normal weight — but those who are only a little overweight actually live longer than people of normal weight. 'It's not surprising that extreme underweight and extreme obesity increase the risk of dying, but it is surprising that carrying a little extra weight may give people a longevity advantage,' said one of the coauthors of the study. 'It may be that a few extra pounds actually protect older people as their health declines, but that doesn't mean that people in the normal weight range should try to put on a few pounds.' The study examined the relationship between body mass index and death among 11,326 adults in Canada over a 12-year period. The study showed that underweight people were 70 percent more likely than people of normal weight to die, and extremely obese people were 36 percent more likely to die. But overweight individuals defined as a body mass index of 25 to 29.9 were 17 percent less likely to die than people of a normal weight defined as a BMI of 18.5 to 24.9. The relative risk for obese people was nearly the same as for people of normal weight. The authors controlled for factors such as age, sex, physical activity, and smoking. 'Overweight may not be the problem we thought it was,' said Dr. David H. Feeny, a senior investigator at Kaiser Permanente Center for Health Research. 'Overweight was protective.'"