This study examines the dynamic relationship between a household’s Food Stamp Program (FSP) participation and the extent to which children in the household are overweight or obese. In contrast to previous studies employing static models, our results suggest that FSP participation significantly affects the deviation of current body mass index (BMI) from the ideal level in older male children who are currently underweight and for older female children who are already overweight. For older male children, the effect is desirable; for older females, however, our findings indicate that FSP participation has an adverse effect on their health and may contribute to being overweight or obese.