In previous research in Brazil, we found socioeconomic and gender differences in body mass and percent body fat, consistent with a model in which individuals in higher socioeconomic strata, especially women, could achieve a cultural ideal of body size and shape. In this article, using new data, we examine these processes more precisely using measures of cultural consonance. Cultural consonance refers to the degree to which individuals approximate, in their own beliefs and behaviors, the shared prototypes for belief and behavior encoded in cultural models. We have found higher cultural consonance in several domains to be associated with health outcomes. Furthermore, there tends to be a general consistency in cultural consonance across domains. Here we suggest that measures of body composition can be considered indicators of individuals' success in achieving cultural ideals of the body, and that cultural consonance in several domains will be associated with body composition. Using waist circumference as an outcome, smaller waist size was associated with higher cultural consonance in lifestyle (β = −0.311, P < 0.01) and higher cultural consonance in the consumption of high prestige foods (β = −0.260, P < 0.01) for women (n = 161), but not for men (n = 106), controlling for age, family income, tobacco use, and dietary intake of protein and carbohydrates. Similar results were obtained using the body mass index and weight as outcomes, while there were no associations with height. These results help to illuminate the cultural mediation of body composition. Am. J. Hum. Biol., 2008. © 2007 Wiley-Liss, Inc.