The mirror's curse: Weight perceptions mediate the link between physical activity and life satisfaction among 727,865 teens in 44 countries

Purpose The purpose of the present study was to examine the link between physical activity (PA) and life satisfaction in a large international study of adolescents. We also aimed to test whether overweight and underweight perceptions act as mediators and whether age and sex acted as moderators. Methods For this purpose, we analyzed data from the Health Behavior in School-aged Children study, which comprises 727,865 observations from 44 nations at 4 measurement occasions. Results Multilevel analyses revealed a positive link between PA and life satisfaction. In addition, underweight and overweight perceptions mediated the effect of PA on life satisfaction. We further found that age and sex acted as moderators. In older adolescents, stronger effects were found in the links between PA and life satisfaction, PA and overweight perception, and both weight perceptions and life satisfaction. In addition, in female adolescents, the link between overweight perception and life satisfaction was stronger. Conversely, the links between PA and both weight perceptions were stronger for boys. Conclusion The results suggest that weight perception explains part of the relationship between PA and life satisfaction in adolescents and that these effects vary as a function of age and sex.