Project Summary Adolescent-onset type 2 diabetes (T2D) is on the rise and a leading cause of severe medical complications, premature morbidity, and early mortality, particularly among adolescent girls of color. Treatment is challenging, making prevention a high priority. Yet, standard lifestyle interventions aimed at preventing T2D show insufficient effectiveness. Extant interventions likely fall short, at least in part, because they primarily focus on directly modifying health behaviors (e.g., physical activity), without addressing the role of broader, developmentally-salient core principles that propel health behavior change. It is critical to identify novel modifiable targets. Extant theory and empirical data suggest that one such target is executive functioning (EF), a set of neurocognitive skills key for executing goal-directed behavior. The aims of this Diversity Supplement application are 1) to examine within-person EF and stress as antecedents of same day and next day changes in physical activity, and 2) to characterize temporal dynamics between EF, stress, and physical activity. Knowledge gained from completion of this project will help guide the development and optimization of future, tailored T2D preventive interventions that leverage neurocognitive processes and the promise of “just-in-time” adaptive interventions (i.e., tailored interventions that provide the right type and amount of support, at the right time, based on an individual’s real-time internal state) as a supplement or alternative to traditional lifestyle approaches. This 2-year Diversity Supplement will also support the career development and research program of the candidate, an early-stage diverse investigator, by providing specialized training and access to outstanding mentors, the resources of premier research institutions, and a committed team dedicated to advancing the training and development of promising behavioral scientists. Together, the research and career development plans outlined in this proposal will allow Dr. Gutierrez-Colina to develop a programmatic line of research and the skills necessary for the submission of a future NIDDK career development (K) award that will facilitate her transition to independence.