Objectives: To describe the relationship between BMI and perceived weight status and to determine how underassessment of weight status is associated with demographic characteristics, self-reported general health, and perceived health risk in relation to one's body weight.

Methods and procedures: In the 2004 Styles surveys, 3,888 US adult participants described their current weight status (underweight, about right, slightly overweight, very overweight), which we compared with self-reported BMI in order to determine concordance. We used multivariable logistic regression to evaluate associations between underassessment of body weight and characteristics of interest.

Results: Among persons with a BMI>or=25, women were more likely than men to recognize their overweight status (slightly or very overweight; 93.0% of women vs. 73.5% of men) and the extent to which they were overweight: 70.4% of obese women vs. 49.5% of obese men described themselves as very overweight. Among the overweight and obese of both sexes, disagreement with regard to current weight as a health risk was associated with underassessment of weight. Additional factors associated with underassessment were education and race/ethnicity among overweight women; race/ethnicity among overweight men; household income and self-rated health among obese women; and self-rated health among obese men (P<0.05).

Discussion: While most of the obese participants recognized that they were overweight, many of them, particularly among the men, did not realize the extent to which they were overweight. Public health messages may be more effective if they are specifically tailored to target audiences, besides emphasizing the health risks associated with excess body weight.