BACKGROUND: Parent involvement varies widely in school-based programs designed to promote physical activity and healthy nutrition, yet the underlying factors that may limit parent's participation and support of learned behaviors at home are not well understood.

METHOD: We conducted a qualitative study that consisted of one focus group (n = 5) and 52 in-depth interviews among parents whose children participated in a school-based physical activity and nutrition (PAN) promotion program in Williamsburg, Virginia, United States. We sought to identify factors that enabled or constrained parent's support of and involvement in children's programs and to understand the underlying factors that contribute to family success in making dietary and physical activity changes at home.

RESULTS: Parents identified their physical and mental health, self-confidence, time, and decision making as underlying "capacities" in the family health pattern. When strengthened, these capacities encourage healthful family behavior and support of school-based PAN programs. Families that succeeded in adopting lessons learned from school-based PAN programs identified four primary strategies for success: shared goals, meal planning, modeling of good behaviors, and collective activities.

CONCLUSIONS: Interventions that aim to improve child nutrition and physical activity and the broader family health environment should consider underlying capacities of parents and the importance of joint goals and activities.