In Brief

Overweight linked to lower death risk in older women

According to the National Heart, Lung, and Blood Institute (NHLBI), the 97 million overweight or obese people in the United States are at risk for various chronic diseases as well as death from all causes. But some research suggests that this may not always be true — at least for older women.

To determine the health effects of overweight and obesity, the NHLBI relies on body mass index (BMI), a measure of weight related to height. (You can determine your BMI using the NHLBI's online BMI calculator, www.nhlbisupport.com/bmi.) You're classified as "underweight" if your BMI is less than 18.5; "normal weight" if it's 18.5 to 24.9; "overweight," if 25 to 29.9; and "obese," if 30 or more.