The Supplemental Nutrition Assistance Program, energy balance, and weight gain

• Examined the effect of SNAP participation on food consumption and physical activity.
• SNAP participation is not associated with significant differences in weight gain.
• Unobserved differences in the propensity for obesity may affect SNAP participation.

Between 2001 and 2006, women participating in the U.S. Supplemental Nutrition Assistance Program (SNAP) weighed 15.5 lb more than eligible nonparticipants on average. Using a dataset (NHANES) that contains detailed information on a wide variety of demographic, socioeconomic, health and behavioral characteristics for 2018 SNAP-eligible women, we make three contributions to the growing literature that addresses this weight difference. First, we specify a physiological model of weight gain with which we show that average differences in caloric intake and physical activity are much too small to explain the weight difference. Second, we estimate regression models that show SNAP participation is not associated with changes in energy balance (i.e., caloric intake and physical activity). Third, we estimate regression models that show SNAP participation does not predict significant weight gain. Our results provide no support for the hypothesis that SNAP participation causes weight gain.