CHICAGO, Ill -- Doctors have discovered something they call the "obesity paradox".
NBC News is reporting that research from Northwestern University's Feinberg School of Medicine is finding that overweight patients with chronic diseases outlive their thinner counterparts.
Data was analyzed from five studies of heart disease and they then zeroed in on those who developed type II diabetes.
Those who had normal body mass indexes were about twice as likely to die during the course of the studies than patients who were overweight or obese.
It is unclear to researchers why this is. Doctors theorize that it may be an issue of the ratio of fat to muscle in body composition. Thinner patients have less muscle, which is critical to controlling blood sugar.