While a poor body image can be harmful, some women's health may be threatened by an overly positive perception of their shape and size, a study suggests.

In a study of 81 inner-city, mostly minority women, researchers found that while two-thirds of the women were overweight or obese, many seemed to see themselves as thinner.

When shown silhouettes depicting various body types, 70 percent of the women chose a normal-weight or moderately overweight figure as being closest to their own. Only five of the 31 obese women chose a silhouette that correlated with their actual weight and shape.

In addition, 20 percent of obese women selected an obese silhouette as their "ideal" body type, the researchers report in the American Journal of Obstetrics and Gynecology.

The findings suggest that many heavy women may be in the dark about their health risks, according to the researchers.

"So the question for doctors then becomes, 'How can we effectively treat our overweight and obese patients, when they don't feel they're in harm's way?'" senior researcher Dr. Marisa Rose, of Temple University Hospital in Philadelphia, said in a statement from the university.

The findings, from a group of mostly African-American and Hispanic women seen at Temple's family planning clinic, add to evidence that many overweight minority women may see themselves as normal-weight.

The current study, according to Rose, "stresses a need for culturally sensitive education for this population."

That means understanding a woman's lifestyle habits from a social and economic perspective, and giving advice in a way that will be most likely to persuade her to change, she told Reuters Health.

"For example," Rose said, "some inner-city African-American women have a diet heavily based on fried food and/or fast food. This diet is deeply rooted in culture and tradition and may also be economically based. Conventional dietary recommendations to avoid all fried foods are not culturally sensitive and are unlikely to be followed by this patient population."

Asking a woman to add fresh fruits and vegetables, while cutting down on some fried foods, might work better, the researcher noted.

Prior studies, Rose said, have shown that such "culturally sensitive messages" can get patients to adopt healthier eating habits.