Association for Public Policy Analysis & Management

Since the 1964 Food Stamp Act, the Supplemental Nutrition Assistance Program (SNAP) has grown to be the nation's largest means-tested welfare program. Despite its goal of providing adequate nutrition for the poor, the program has been questioned for being responsible for the contemporaneous growth of obesity among low-income population. Although evidence of SNAP effects on obesity is mixed and estimated effects on diet quality range from modest improvement in healthy food consumption to contributing to unhealthy obesogenic diet, lawmakers have proposed modification of SNAP rules to ban SNAP usages on unhealthy food items and subsidize healthier items.

This study uses the National Household Food Acquisition and Purchase Survey (FoodAPS) to examine whether SNAP benefits have an effect on nutritional quality of diet. Specifically, this study examines (1) whether additional SNAP dollars result in either more or less healthful diet of households, and (2) whether the effect of SNAP dollars on diet quality is different from the effect of income from other sources. 

The FoodAPS is a survey of nationally representative sample of 4,826 households on detailed records of foods acquired or purchased for both at-home and away-from-home consumption during the seven-day reporting period. Based on the food acquisition record, nutritional measures directly relevant to obesity such as energy density and percent of empty calories are computed. Beside extensive demographic and program participation information at the individual level, the FoodAPS also contains SNAP benefit amounts based on self reports, mathematical simulations, and administrative match. To address the endogeneity or selectivity bias of SNAP benefits, we follow Almada & Tchernis (2016) and identify the exogenous variation of benefit amounts due to the variability of the share of family members eligible for school-based food assistance programs. 

Preliminary results suggest that SNAP has no significant impact on energy density or on percent of calories from solid fat, alcohol, and added sugars. Findings from this study contributes to more accurate assessment of the feasibility of potential modification of SNAP rules.