The impact of obesity on human capital accumulation: Exploring the driving factors

This paper examines the impact of childhood obesity on Spanish high school students' academic achievement and human capital accumulation. To address potential endogeneity concerns, we exploit exogenous variation in obesity within peer groups, using data from friendship networks. Specifically, we instrument individual obesity with the average body mass index of intransitive friendship triads. Our results indicate that obesity has a negative effect on academic outcomes, particularly on overall grades for girls and on cognitive abilities for both boys and girls. We also find a negative impact of obesity on girls' mathematics scores, whereas boys experience a positive effect. We identify several key drivers underlying these relationships, including class fixed-effects, which potentially reflect teacher bias, psychological well-being, and expectations related to labor market discrimination.