This report uses 1985-2000 data from the 1979 cohort of the National Longitudinal Survey of Youth to examine the effects of the Food Stamp Program on obesity. The effects are found to differ by gender, level of benefits, and duration of participation. Results suggest that, for females, current program participation increases Body Mass Index (by 0.5 index point on average) as well as the probability of being obese (between 2 and 5 percentage points). Current program participation was not found to have significant effects for males. Long-term participation is found to increase obesity for females and males.