Project Summary Childhood obesity remains a significant public health problem and obesity risk begins early in life. There is a need for accessible and comprehensive interventions focused on modifiable behaviors in infancy. This proposal is an efficacy trial for the virtual Mothers and CareGivers Investing in Children (MAGIC) FEED+ program designed to foster responsive bottle and infant feeding and healthy eating habits starting in infancy, compared to an attention control arm. Our pilot work has successfully implemented the MAGIC-FEED program with responsive feeding coaching and focusing on complementary feeding to under and un-insured families in the Austin area. The proposed research builds upon our partnerships and expands the intervention period to earlier in infancy to include responsive bottle- and breast-ffeeding and includes longer-term follow up of infants to disentangle the role of the intervention on child self-regulatory behaviors and longer-term adiposity. Our trial will enroll 266 predominately low-income and Hispanic caregivers in early infancy and will deliver the intervention starting at child age 3 weeks with intervention visits at 3 weeks, and 3, 6, 8, and 10 months. In- person assessments of growth and body composition and child self-regulation will occur at child age 3 weeks, and 13 and 24 months. Aim 1 focuses on main intervention effects on child growth and body composition. Aim 2 focuses on intervention effects on caregiver nutrition knowledge, and quality, caregiver responsive feeding and child self-regulation, and examines the effect of MAGIC-FEED+ and the role of potential drivers of growth (caregiver feeding practices and child self-regulatory skills) in infancy on children’s propensity to eat in the absence of hunger and adiposity/body fat at 24 months. Aim 3 determines whether MAGIC-FEED+ demonstrates the factors necessary to be a successful intervention for broader dissemination. This proposal is the first dynamic and interactive virtual trial designed to support heathy breast-, bottle and complementary feeding with robust measurements of responsive feeding, self-regulation and adiposity. These results will inform a pragmatic trial, and if effective, the MAGIC-FEED+ program is poised for wide dissemination and public health impact.