Peer Effects, Fast Food Consumption and Adolescent Weight Gain*

Short Summary:

Can friendship influence adolescent weight gain? Using Add Health data on US secondary schools, this paper indeed finds the presence of positive peer effects, significant though small, on junk food consumption. The results indicate for example that, in the long term, an additional weekly meal at a fast food restaurant increases adolescent standardized body mass index by 4.5% when peer effects are ignored and by 5.1% when peer effects are taken into account, this net effect being higher than the individual effect because friendship networks help transmit bad eating habits.