African American women and their female children have the highest obesity prevalence of any demographic group in the United States, and they are also most likely to underestimate their body weight, according to a paper from Rush University Medical Center.

The authors say cultural norms for body size may prevent awareness among many African American women about the potential risks of obesity and the benefits of weight loss.

Led by Elizabeth Lynch, PhD, the study recruited African American women in a low-income neighborhood of Chicago. All 69 participants were full-time caretakers of at least one child and the mean age of the subjects was 38 years. For the study, women were asked to use the Body Image Scale to classify figures on the scale as overweight, obese, or too fat and identify their own body size.

This is a body image scale adapted with permission from Obesity Pulvers et al. (2004). It shows the development of a culturally relevant body image instrument among urban African-Americans. Obesity Res. 2004;12:1641-1651.Credit:  Journal of Nutrition Education and Behavior

Regardless of their weights, women in this study agreed which figures on the Body Image Scale were overweight, obese, and too fat. The majority classified Body Figures 6–9 as overweight and Body Figures 8 and 9 as obese and too fat. Therefore, overweight body sizes were not considered too fat. In fact, having the women classify their own body size according to cultural definitions revealed a large chasm between biomedical and cultural definitions of body size. The 56% of overweight women (BMI 25 or greater) and 40% of obese women (BMI 30 or greater) did not classify their body size as overweight, obese, or too fat. The cultural threshold for overweight was determined to be about a BMI of 35, which is higher than the medical definition of ≥25.

"Interestingly, research suggests that weight threatens mortality at a BMI>35, so perhaps the cultural definition captures some important health effects associated with larger body sizes. But the fact that women felt that overweight body sizes were not too fat suggests that being told they are overweight, even by a physician, may not be sufficient motivation for them to attempt to lose weight," Lynch said.

Although there were limitations to this study, namely self-reporting of height and weight data for BMI calculation, the results further understanding of attitudes among African American women about body weight and image. Specifically, this study goes further than others in identifying the cultural belief that overweight bodies are not too fat. Thus, the researchers believe more effort toward education regarding body size should be exerted, and biomedical definitions of body size should be taught using visual aids.