Mediating effect of fitness and fatness on the association between lifestyle and body dissatisfaction in Spanish youth

Abstract

Background: Previous studies have identified sedentary behaviour, physical activity and eating habits as variables that define a healthy lifestyle. The aims of this investigation were to determine the association between lifestyle and body dissatisfaction, as well as to test the mediating effect of fatness and fitness in this relationship in adolescents.

Methods: The sample comprised 2216 adolescents aged 13.1 ± 0.90 years, of whom 980 were girls (age 13.1 ± 0.86) and 1236 were boys (age 13.1 ± 0.92). Body composition was measured by body mass index, neck circumference, waist to height ratio and body fat percentage, whereas physical activity, sedentary time, body dissatisfaction and eating habits were self-reported. Physical fitness was evaluated through the ALPHA-Fitness Battery.

Results: The results showed that lifestyle was negatively related with body dissatisfaction. Moreover, physical fitness (β = -0.062; SE = 0.022; 95% IC [-0.106, -0.017]) and fatness (β = -0.052; SE = 0.011; 95% IC [-0.075, -0.032]) showed a significant mediation effect on the relationship between lifestyle and body dissatisfaction. The bootstrapped confidence intervals for the indirect effect were statistically significant, suggesting the mediation effect of fatness (percentage of the total effect of 51.0%) and fitness (percentage of the total effect of 21.3%) on the relationship between healthy lifestyle and body dissatisfaction.

Conclusion: The study suggests that adolescents with a healthy lifestyle may have less body dissatisfaction. Fatness and physical fitness can positively affect this relationship, decreasing young people's body dissatisfaction. Therefore, this study highlights the importance of a healthy lifestyle on physical and psychological health in adolescence.

Keywords: Adolescents; Body dissatisfaction; Body mass index; Physical activity; Sedentary behaviour.