Low-income, multi-ethnic women are at elevated risk for obesity and chronic diseases, yet influences at different levels may act as barriers to changing risk behaviors. Following the birth of a child, childrearing and social isolation can exacerbate these influences. The social ecological framework integrates behavior-change strategies at different levels, providing a strong theoretical base for developing interventions in this high-risk population. The primary purpose of this randomized controlled trial is to test the efficacy of an educational model delivered by community-based paraprofessionals in improving diet, activity and weight loss among new mothers over a 12-month postpartum period and a 6-month maintenance period. This model fosters institutional change to support behavior changes influenced at intrapersonal and interpersonal levels, through collaboration with federal programs for low-income families: the Special Supplemental Food Program for Women, Infants and Children (WIC), and the Expanded Food and Nutrition Education Program (EFNEP). Participants are randomized to the Usual Care, e.g. WIC nutrition and breastfeeding education, or Enhanced EFNEP intervention arm, consisting of Usual WIC Care plus a sustained, multi-component intervention including home visits, group classes and monthly telephone counseling. If shown to be efficacious, this program will be readily sustainable through existing federal agencies.