The results also show that stereotypes about body size can be misleading and that even "less voluptuous" people can have risk factors commonly associated with obesity, said study author MaryFran Sowers, a University of Michigan obesity researcher.
"We're really talking about taking a look with a very different lens" at weight and health risks, Sowers said.
In the study, about 51 percent of overweight adults, or roughly 36 million people nationwide, had mostly normal levels of blood pressure, cholesterol, blood fats called triglycerides and blood sugar.
Almost one-third of obese adults, or nearly 20 million people, also were in this healthy range, meaning that none or only one of those measures was abnormal.
Yet about a fourth of adults in the recommended-weight range had unhealthy levels of at least two of these measures. That means 16 million of them are at risk for heart problems.
It's no secret that thin people can develop heart-related problems and that fat people often do not. But that millions defy the stereotypes will come as a surprise to many people, Sowers said.
Not sure we want to float this kind of information out there. Americans are already fat enough. And according to this report, obesity and clumsiness could go hand in hand—via Reuters.