Recent research suggests that obese women often tend to think they are of normal weight and underweight women tend to think otherwise. Most often they even correlate their weight with race.

Black and Hispanic women often tend to play down their overweight status compared to whites. In effect, being overweight has become the norm.

Research has found that 30 per cent of Americans in the "overweight" class believed they were actually normal size, while 70 per cent of those classified as obese felt they were simply overweight.

"If you go somewhere, you see all the overweight people that think they are normal even though they're overweight," said Rahman, assistant professor of obstetrics and gynecology at the Center for Interdisciplinary Research in Women's Health, University of Texas.

Another study looked at more than 2,200 women, at a public-health clinic. More than half of these women between ages 20 and 39 tended to have a higher BMI. About 82 per cent of them who were Blacks and 75 per cent of Mexican Americans were obese.Those who were educated, were inclined to understand their bodies better, researchers noted.

They also noted such notions of an individual’s weight status can have implications for behavior, and perhaps health.

"Unfortunately, women can't do anything to lose weight if they don't perceive themselves as overweight. It does start there," said Keri Gans, a registered dietician based in New York City and a spokeswoman for the American Dietetic Association. "If they don't perceive themselves as overweight, they're not going to adopt healthy behaviors to lose weight and prevent disease. Meanwhile, the normal-weight people who don't recognize they're at normal weight are engaging in behaviors that put them at risk for illness."