It's not a license to pig out, but a recent study found that women considered overweight by some measures had lower mortality than their skinnier counterparts.

A study of more than 8,000 women ages 65 and older participating in the Study of Osteoporotic Fractures found those with body mass indexes (BMI) ranging from 24.6-29.8 kg/m2 had the lowest mortality. BMI charts typically place women with a BMI of 25-29.9 kg/m2 as overweight.

During the study's eight-year follow-up period, 945 women died, and mortality was lowest among those in the middle of the distribution of each body size measure used. The study's authors pointed out that using a single set of numbers to define overweight and obesity in different age groups "may not be appropriate" because several studies have shown the increase in death risk among women as BMI increases is greater among younger women than older women. "It is not surprising that the women at lowest risk for mortality are neither the most thin nor the most obese," the study's authors said.

What was a surprise: women with the lowest mortality rate would be classified as overweight or almost obese by traditional BMI charts.

[From: "Associations between body composition, anthropometry, in mortality of women aged 65 and older." Contact: Chantal Matkin Dolan, PhD, Stanford University.]