Overweight adults can afford a few extra pounds - but there's a catch

A new study suggests that some older adults might not need to lose weight in order to live longer.

The catch, however, is that they can't pack on any extra pounds.

A nationwide survey found that slightly overweight people in their 50s who kept their weight relatively stable had the best chances of survival over the next 16 years. The surprising part? These individuals had better survival rates than even normal-weight individuals who gained a few pounds.

Changes in weight are key

Hui Zheng, lead author of the study and assistant professor of sociology at Ohio State University, said the results indicate that fluctuations in weight may be more important indicators of health than starting weight at a given age.

"You can learn more about older people's mortality risk by looking at how their weight is changing than you can by just looking at how much they weigh at any one time," Zheng said.

Not surprisingly, people in the survey who were very obese in their 50s and continued to gain weight were the most likely to die early. In fact, 7.2 percent of deaths after the age of 51 could be attributed to weight gain among obese people in the study.

Small gain is OK

Participants in the survey were classified into six groups, based on their body mass index (BMI) at the beginning of the study and how it changed over 16 years.

Slightly overweight people - with a BMI of 25 to 29.9 - who maintained a steady weight had the highest survival rates, followed by people who moved from overweight to obese (BMI of 30 to 34.9).

"This suggests that among overweight people at age 51, small weight gains do not significantly lower the probability of survival," Zheng said.

How is being overweight a protective factor? Zheng said that, in the older population, diseases like cancer are more likely, which can cause dangerous weight loss.

"In that case, a small amount of extra weight may provide protection against nutritional and energy deficiencies, metabolic stresses, the development of wasting and frailty, and loss of muscle and bone density caused by chronic diseases."

Younger people, however, aren't protected by extra pounds, Zheng noted. And added weight usually means higher chances of disease, regardless of age.

"Continuing to put on weight can lower your life expectancy," he concluded.

Zheng's study is published in the American Journal of Epidemiology.

Source: Ohio State University