Body-weight perception and related preoccupations in a large national sample of adolescents.

Summary Objectives This study aimed to investigate the association between body-weight (BW) perception, weight preoccupation and behaviour, including weight control practices and compulsive over-eating episodes, across gender and actual BW classes. Design This study used a cross-sectional observational study. Participants A large, nationally representative sample of 6404 ninth-grade French adolescents was randomly selected from schools throughout France. Methods Weight and height were measured, and BW preoccupation, BW control practices and compulsive over-eating were self-reported using standardized questionnaires. Results Nearly one-third of adolescents misperceived their BW. Misperception was more frequent among girls than boys (42.2% vs. 27.3%, P < 0.01). Underestimation of BW among overweight adolescents, like BW overestimation among underweight adolescents, was associated with less preoccupation with weight and fewer weight control practices than accurate perception of BW. Normal weight adolescents who overestimated their BW were more likely to declare weight preoccupations (ORa = 8.66 [6.67–11.25]), dieting (ORa = 4.81 [3.68–6.27]) and recurrent compulsive over-eating episodes (ORa = 2.36 [1.72–3.23]) compared with their counterparts who correctly estimated their BW. Conclusion Our study underlines the role of these associations in each category of actual BW (underweight, normal weight and overweight) in a large national sample.