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Abstract
Childhood obesity has tripled since the 1980s, and in 2001, the U.S. Surgeon General called for policies to change environments to prevent and reduce childhood obesity. This research studies the school food environment. It considers one channel through which unhealthy food is available to students at school and examines its effect on students' weight status. It offers the first study of the economics of obesity to correct self-reporting error in adolescent weight measures.
I use unique student-parent-and-school matched survey responses collected from a small sample of Nebraska schools to estimate the effect of prohibiting junk food in the à la carte lines at breakfast and lunch on the probability students are overweight or obese. I isolate the effect by controlling for various individual and family influences such as genetics, socioeconomic status, the students' self-esteem, electronic media use, and sports participation, and the parents' physical activity, monitoring behavior, and work characteristics.
I account for the potential endogeneity of the school food policy by using several attitude levels of the parents as instruments: the parents' attitude toward obesity as a social issue, toward government control, and toward the economic functioning of advertising. I correct for self-reporting bias in both the dependent and explanatory variables by using an estimation method developed by Lee and Sepanski (1995). Self-reporting bias is induced because the weight status variables are constructed from self-reported versus measured height and weight values. I estimate the standard errors to account for sampling error, a by-product of the correction procedure, by using Haukka's (1995) bootstrap method.
My results suggest that prohibiting junk food sales in school is a potentially effective policy to reduce overweight or obesity among students. The estimated effect indicates that for the typical student attending a school prohibiting foods with minimal amounts of vitamins and minerals and high amounts of added sugars à la carte reduces the probability of being overweight or obese by about 45 percentage points.
