Body image and association with BMI, and purgative behaviours for weight control in adolescents aged 11-14 years.

We aimed to evaluate the association of overweight/obesity based in BMI and purgative behaviours with body image (BI). Methods: Cross-sectional study, with probabilistic sample of 976 adolescents, aged 11-14 years, from the city of Florianópolis, Brazil. Multivariate analyses were performed. Overweight (including obesity) and four variables related to purgative methods for body weight control or eating behaviour were evaluated as outcomes, while BI satisfaction was the primary independent variable in each model. Models were controlled for age, sex, type of school (public or private), intake of fruit and vegetables, number of daily meals, and physical activity scores levels. A total of 31·4 % of adolescents wanted to enlarge their silhouette and 45·6 % wanted to reduce it. Among overweight/obese adolescents, 9·6 % were satisfied with their bodies, while 89·8 % wanted to reduce it, while among the not overweight/obese adolescents, 45·4 % wanted to enlarge their silhouette ( P < 0·001). Multivariate analysis showed that the odds for overweight/obesity is higher among adolescents who wanted to reduce their silhouette (OR = 11·20; 95 % CI = 5·55, 22·58). Adolescents who want to reduce their silhouette are more likely to use diuretics (OR = 3·08; CI = 1·78, 5·32) and to use laxatives (OR = 2·10; CI = 1·20, 3·68). A significant association was also found between dissatisfaction with BI and overeating (among those who want to enlarge their silhouette: OR = 1·78; CI = 1·12, 2·85 and among those who want to reduce their silhouette: OR = 1·81; CI = 1·03, 3·19). Conclusion: BI dissatisfaction was associated with overweight/obesity, as well with overeating, and the use of purgative methods.