IntroductionThis study explores the associations of weight perceptions with actual body mass index (BMI) and attempts to lose weight in a nationally representative sample of a pediatric population.Material and methodsData were collected from school students of 27 provinces in Iran, as part of “the national survey of school student high risk behaviors”. We used t-test for continuous data and chi square test for categorical data. The correlation between categorical variables was assessed by Cramer's phi test. A multiple nominal logistic regression model was fitted to data to assess the association between perceived body weight and gender by adjusting for potential confounding variables.ResultsThe study participants consisted of 5570 (2784 girls, 70% urban) students with mean age of 14.7 ±2.4 years. Overall, 17.3% of students were underweight, and 17.7% were overweight or obese. Nearly 25% and 50% of participants reported themselves as appropriate weight and very obese, respectively. In both genders, the strength of association between perceived weight and actual BMI was quite high (Cramer's phi coefficient = 0.5, p < 0.0001), and that of perceived body weight with trying to lose weight was moderate (Cramer's phi coefficient = 0.2, p < 0.0001). Overweight students were more likely than their obese peers to try to lose weight. After adjusting for possible confounders, the chance of perceiving oneself as very obese compared to perceiving oneself as very thin was 1.56-fold higher in girls than in boys, i.e. OR (95% CI): 1.56 (1.27-1.91).ConclusionsThis study revealed a considerably frequent “mismatch” between actual weight status and body shape dissatisfaction, which supports the necessity of increasing public awareness in this regard.