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In 2012, the Healthy, Hunger-Free Kids Act (HHFKA) placed strict nutritional mandates on food served at public schools. This policy change offers a unique opportunity to study household response to a large, exogenous change in healthiness of food available to their children. Did more healthy school meals lead households to substitute towards them, and away from grocery food purchases? Or did the opposite happen as detractors of the HHFKA had predicted? Which households were more responsive to the nutritional mandates? And was there a spillover effect on the healthiness of their grocery food purchases? We examine these questions in this research.
We first estimate average effects of the policy on grocery food quantity and quality with a Difference-in-Difference analysis of changes in the shopping of treatment households (with school-age kids) and a matched control group of households without kids. We document a meaningful decrease in the quantity of grocery food purchased in response to the HHFKA, and a small decrease in quality. Consistent with substitution towards now-healthier school meals, much of this shift comes from items likely to be purchased for children and categories traditionally associated with breakfast and lunch (the meals served at school).
We then examine household heterogeneity in the treatment effect by exploring the role of financial constraints, time constraints, and nutrition knowledge (three factors that are known to drive both school meal participation and healthiness of food choices). We do this both with a moderated D-i-D analysis and heterogeneous treatment effects estimated using causal forest. We find that the HHFKA attracted even greater participation from financially and time constrained households for whom the pre-existing benefits of school meals were already important and were now coupled with the additional benefit of healthier food. It also had a stronger pull among those who were previously purchasing less healthy grocery food.