A new study finds that being overweight -- but not obese -- might help you live longer.
In the study of more than 11,000 Canadian adults, overweight people lived longer than normal-weight people, while those who were either extremely obese or underweight died at an earlier age than normal-weight people.
The findings do not mean that normal-weight people should try to pack on extra pounds, the researchers said.
"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," said study co-author Mark Kaplan, a professor of community health at Portland State University.
The study followed 11,326 adults in Canada for 12 years. Compared to normal-weight people, those who were underweight were 70 percent more likely to die and those who were extremely obese were 36 percent more likely to die, the researchers found.
On the other hand, overweight people were 17 percent less likely to die than those of normal weight. The risk for obese people was the same as for people of normal weight, the study authors noted.
Overweight was defined as a body mass index (BMI) between 25 and 30, and obesity was defined as BMI of 30 and above. BMI is a measurement based on weight and height. For example, a 5-foot 10-inch man weighing 181 pounds has a BMI of 26; a 5-foot 6-inch woman weighing 210 pounds has a BMI of about 34.
The study was published online June 18 in the journal Obesity.
"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," co-author David Feeny, a senior investigator at the Kaiser Permanente Center for Health Research in Portland, Ore., said in a Kaiser news release.
But Kaplan noted that there's more to health than just living longer. "Our study only looked at mortality, not at quality of life," he pointed out, "and there are many negative health consequences associated with obesity, including high blood pressure, high cholesterol and diabetes."
Being healthy involves more than body mass index (BMI) or the number on a bathroom scale, said Dr. Keith Bachman, a weight management specialist with Kaiser Permanente's Care Management Institute.
"We know that people who choose a healthy lifestyle enjoy better health: good food choices, being physically active every day, managing stress, and keeping blood pressure, cholesterol and blood sugar levels in check," Bachman said in the news release.