MONDAY, Nov. 22 (HealthDay News) -- Almost one-quarter of young women who are overweight actually perceive themselves as being normal weight, while a sizable minority (16 percent) of women at normal body weight actually fret that they're too fat, according to a new study.

The study found these misperceptions to be often correlated with race: Black and Hispanic women were much more likely to play down their overweight status compared with whites, who were more apt to worry that they weighed too much (even when they didn't).

Although the study looked mostly at low-income women attending public-health clinics in Texas, the findings do mirror other studies in different populations, including a recent Harris Interactive/HealthDay poll.

That survey found that 30 percent of adult Americans in the "overweight" class believed they were actually normal size, while 70 percent of those classified as obese felt they were simply overweight. Among the heaviest group, the morbidly obese, 39 percent considered themselves merely overweight.

The problem, according to study lead author Mahbubur Rahman, is the "fattening of America," meaning that for some women, being overweight has become the norm.

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

In fact, "they may even be overweight or normal-weight and think they are quite small compared to others," added study senior author Dr. Abbey Berenson, director of the Center for Interdisciplinary Research in Women's Health at UTMBG.

The new findings are published in the December issue of Obstetrics & Gynecology.

The study looked at more than 2,200 women who had arrived at a public-health clinic for reproductive assistance, such as obtaining contraceptives.

According to the study authors, more than half of these reproductive-age women (20 to 39 years), who were the subject of this trial, were above a normal body mass index (BMI). An even higher proportion of black Americans (82 percent) and Mexican Americans (75 percent) were overweight or obese.

Women were classified into one of four groups: "overweight misperceivers," meaning overweight women who thought they were normal-weight or even underweight; "overweight actual perceivers," who accurately perceived their size; "normal-weight misperceivers" who worried they were too heavy; and "normal-weight actual perceivers," meaning those whose perceptions were in sync with the weigh-scale.

According to the study, 23 percent of overweight women saw themselves as being smaller than they were, while 16 percent of normal-weight women worried they were too big.

Race seemed to play a role in self-perceived weight. Among overweight women, 28 percent of blacks and about 25 percent of Hispanics considered their weight within the normal range, compared to 15 percent of overweight white women. The trend was the opposite among normal-weight women, with more whites (16 percent) believing they were fat, compared to just 7 percent of blacks.

Women who had more education and surfed the Internet were more likely to be in tune with their actual body size, the researchers said.

Mistaken notions of one's weight status can have implications for behavior, and perhaps health, the researchers noted. For example, women who were overweight but thought they were normal size were less likely to try to lose any excess weight by dieting or other means. On the other hand, women who saw themselves as fatter than they were, were more likely to use diet pills or diuretics, to induce vomiting or to smoke cigarettes, often as ways to control or lessen their weight.

"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."

Women need to be aware of what "normal" actually is, in terms of numbers. And weighing yourself isn't the only way, and may not even be the best way, to monitor creeping weight gain, Gans said.

"I don't think the only way to maintain body weight is to weigh yourself," she said. "You know when your pants are too tight. You don't need a number to tell you that."

More information

To check your BMI, head to the U.S. National Heart, Lung, and Blood Institute.