Background: To examine the association between body size perception (BSP) and body size dissatisfaction (BSD) in elementary school children and to document the potential contribution of individual factors [age, sex, and actual body size (BMI Z-scores: BMIZ)] that may influence their relationship. Methods: This study included 269 children (124 boys and 145 girls) between 6 and 13 years of age (9.2 ± 1.6 years). The BSP score was calculated as the difference between the perceived actual body size and BMIZ (actual body size). A negative BSP score indicated an underestimation of their body size. To assess the BSD score, the difference between perceived actual body size and desired body size was calculated. A positive BSD score indicated a desire to be thinner. Results: Perceived actual body size was smaller than BMIZ, independent of age group and weight status. Overall, 64% of children underestimated their body size. The young children living with obesity demonstrated the highest misperception. Results also showed that the proportion of children who desired to be thinner was higher in overweight and obese subgroups. No significant relationship was found between BSP and BSD scores in the entire sample, while a positive association was observed among younger children in the normal-weight and obese subgroups (r = 0.40; p < 0.001 and r = 0.78; p < 0.05, respectively). Conclusions: Underestimation and dissatisfaction of body size are more prevalent in children living with overweight/obesity. Moreover, there is an association between BSP and dissatisfaction, yet this association is dependent on age and weight status.
Keywords: BMI; body size evaluation; childhood obesity; overweight; self-perception.