An examination of the effectiveness and feasibility of two obesity prevention interventions--the Preschool Obesity Prevention Series (POPS) and POPS plus the Incredible Years Series (IYS), an evidence-based approach to improving self-regulation among preschool-aged children, delivered by community-based nutrition educators and Head Start staff to low income preschoolers and their parents, based on data from 600 low income Michigan Head Start preschoolers and their parents