Project Summary Racial disparities in overweight and obesity among Black children compared to White children begin early in development and continue throughout the lifespan. Infancy is a critical period for later obesity risk, and rapid weight gain during infancy is one of the most consistent risk factors associated with later overweight and obesity. Despite these well-established associations and the clear need for intervention, there has been limited attention to modifiable behavioral, social/contextual, and biological determinants of early rapid weight gain and to approaches to prevent excess infant weight gain among African American infants living in underserved, low SES contexts. Multi-component responsive parenting programs that teach parents to interact with their child in ways that are responsive, appropriate, and contingent hold great promise in reducing rapid weight gain and later obesity risk, but remain largely untested in this population and may be too burdensome to implement in their existing form in these high-stress contexts. Furthermore, the potential for moderation of intervention effectiveness by stressors common to underserved populations, including depressive symptoms, poverty, and relationship strain, has not been considered. The current proposal seeks funding to examine the impact of a responsive parenting intervention focused on infant sleep and soothing to reduce rapid weight gain among African Americans living in underserved, low SES contexts in the rural South. To do this, we propose a microtrial, a short-term longitudinal randomized experimental design that can provide a more focused test of the efficacy of a single intervention component and the conditions under which this component is efficacious. Specifically, we plan to pursue the following specific aims: (1) To assess the effects of responsive parenting, focused on infant sleep and soothing, on reducing rapid weight gain from 2 weeks to 8 weeks among African American infants; (2) To assess effects of responsive parenting on parental and infant behaviors (sleep, soothing, and feeding), and whether these behaviors mediate effects on infant growth; and (3) To examine moderation of intervention effects by individual and contextual factors common among African American mothers. The proposed microtrial represents an important step in efforts to better intervene to reduce obesity risk among rural African Americans by understanding factors in infancy that affect long-term outcomes. Data from this project will be used to inform the development of a multi-component program tailored to this high- need context in order to prevent child obesity.