Health behavior and academic achievement among adolescents: The relative contribution of dietary habits, physical activity, body mass index, and self-esteem

This study tested a structural equation model to estimate the relationship between health behaviors, body mass index (BMI), and self-esteem and the academic achievement of adolescents. The authors analyzed sur-vey data from the 2000 study of Youth in Iceland, a population-based, cross-sectional sample of 6,346 ado-lescents in Iceland. The model demonstrated good fit with chi-square of 2685 (n = 5,810, df = 180), p <.001, Comparative Fit Index value of.94, and a root mean square error of approximation of.049. Lower BMI, phys-ical activity, and good dietary habits were all associated with higher academic achievement; however, health behavior was positively and robustly associated with greater self-esteem. Self-esteem was positively influ-enced both through physical activity (β =.16) and the consumption of fruits and vegetables (β =.14). In con-trast, poor dietary habits negatively influenced self-esteem and academic achievement, and self-esteem was negatively influenced by increasing levels of BMI (β = –.05)