When compared to those with normal weight, people who were overweight or obese had no increased risk of death during a follow-up period of six years. People who were severely obese did have a higher risk, but only if they also had diabetes or hypertension.

The findings, which appear in the July-August issue of The Journal of American Board of Family Medicine, call into question previous studies -- using data collected when obesity was less common -- linking higher short-term mortality with any amount of extra weight.

"There is currently a widespread belief that any degree of overweight or obesity increases the risk of death, however our findings suggest this may not be the case," said Anthony Jerant, professor of family and community medicine and lead author of the study. "In the six-year timeframe of our evaluation, we found that only severe obesity was associated with an increased risk of death, due to co-occurring diabetes and hypertension."

Based on the study, Jerant recommends that doctors' conversations with patients who are overweight or obese, but not severely obese, focus on the known negative effects of these conditions on mental and physical functioning, rather than on an increased short-term risk of death.