Obese people have a blind spot when it comes to their own weight problem, according to a study that showed only 15 percent of people in that category view themselves as obese.

Such a lack of self-awareness can be deadly.

"If somebody doesn't perceive themselves to be obese, they are most likely not going to pay attention to any public health information about the consequences of obesity," said Kim Truesdale, a nutrition researcher at the University of North Carolina at Chapel Hill.

Among those consequences are heightened risk of heart disease, diabetes, high blood pressure and arthritis.

The study of 104 adults, ages 45 to 64, showed that only 15 percent of people who fit the body type for obese correctly classified themselves that way.

In contrast, 71 percent of normal-weight people and 73 percent of people classified as overweight were accurate in their self-assessments.

"I think part of the disconnect is just the overall image people have when you say 'obesity,'" said Truesdale, who presented her findings recently at conference in San Francisco. "They see someone who's 400 pounds, maybe morbidly obese. They don't think about the person who's 5-10 and you weigh 208, 209 pounds and you are technically obese. You can probably think of a lot of men who are 5-10 and over 200 pounds."

A 5-foot-10-inch adult — both male and female — is overweight at 174 pounds and obese at 209, according to the U.S. Centers for Disease Control and Prevention.

John Cawley, a researcher at Cornell University who has studied body image, questioned the study's reliance on body-mass index as a measure of obesity. He said many researchers view BMI — a ratio of a person's weight and height — as being of limited use.

"BMI does not take into account body composition — weightlifters and other athletes may be classified as clinically obese because their weight is high even though they have almost no fat," Cawley said.

On a Web page that discusses BMI, the federal Centers for Disease Control and Prevention makes a similar point, giving the example of a 6-foot-3 man who weighs 220. A BMI ratio of 27.5 defines that man as overweight when in reality he could be anything from a musclebound bodybuilder to a schlumpy couch potato.

"BMI is only one piece of a person's health profile," the CDC notes.

Unfortunately, as many experts note, most Americans are not overweight because of an excess of muscle. And more than two-thirds of the country is fat.

The CDC's latest survey reported 71 percent of men are overweight and 31 percent are obese. For women, it's 62 percent overweight and 33 percent obese.