Effects of physical activity, fitness and fatness on children's body image: The Australian LOOK longitudinal study

Background: Among children relationships between body image and body fat are well documented but less attention has been given to relationships with physical activity and fitness. This study examined longitudinal relationships of children's body image with physical activity, fitness and percent body fat whilst accounting for a number of potential confounding variables. Method: Participants were 821 elementary-school children across 29 schools from the Lifestyle of our Kids (LOOK) study. Measures of body image, body fat (DXA), physical activity (pedometers) and fitness (shuttle run) were collected in grades two, four and six. Results: The current study found longitudinal evidence that increases in %BF among primary school-aged girls is associated with greater body dissatisfaction and cross-sectional evidence of the same relationship among boys. Among both boys and girls, lower levels of cardiovascular fitness were associated with greater body dissatisfaction cross-sectionally, even after adjusting for percent body fat. Weaker evidence was found for the relationship between physical activity and body dissatisfaction and these relationships were no longer significant after adjusting for percent body fat. At the between-school level we found significant and positive relationships between body dissatisfaction and physical activity among girls and with percent body fat for boys, indicating that school culture may significantly affect body dissatisfaction. Conclusion: Increased adiposity is a strong predictor of body dissatisfaction, particularly among girls. Higher levels of cardiovascular fitness may act as a protective buffer to body image concerns, regardless of a child's body composition. Future interventions may benefit from targeting change in school culture.