The Persistence of Healthy Behaviors in Food Purchasing

When a policy gives temporary incentives for healthy behaviors, how long does the impact last? The U.S. Special Supplemental Nutrition Program for Women, Infants, and Children gives food vouchers to young children and their mothers. Using household-level scanner data, I study the reform of the program that introduced vouchers for healthier products. The difference-in-differences analysis shows that the reform makes purchases healthier during the program participation in the product categories most targeted by the reform (bread and milk). However, the effect is not always persistent. For bread, the effect decreases significantly within a couple of years after participants exit the program. Demand model estimates imply that price differences between healthy and unhealthy products play a large role in decreasing the program’s impact. Therefore, some differences in the persistence can be explained by the relatively higher prices of healthy foods. Counterfactual analysis shows that a modest postprogram subsidy might be a sustainable way to lengthen the program’s impact and lead to long-term healthier purchases.