PROJECT SUMMARY / ABSTRACT Breast cancer (BC) is the leading cause of cancer death among US Latinas. Latinas are at high risk of obesity and obesity-related diseases, which are associated with poorer cancer outcomes. There is a significant lack of an effective intervention to address the diverse needs of Latina BC survivors to achieve a healthy weight. We have developed and tested multi-component weight loss, dietary change, and physical activity (PA) interventions among BC survivors, with a focus on experiential learning (EL) among Latinas. As the next step, we propose a sequential multiple assignment randomized trial (SMART) testing 12 month adaptive culturally- tailored weight loss interventions in a geographically diverse group of Latina BC survivors. The adaptive interventions will use the CDC’s Diabetes Prevention Program (DPP), an evidence-based weight loss program, as the central educational component. Based on our prior work, we will adapt the DPP to be remotely delivered, include information specific to BC survivors, and be culturally-tailored to Latinas. Women will be recruited via 3 West Coast SEER registries. Inclusion criteria: Diagnosis of stage I-III BC within 5 years, no evidence of recurrent disease, >60 days post-treatment, and body mass index (BMI) 30 kg/m2. Baseline, 1, 3, 6, and 12 month assessments will include questionnaires on medical history, diet, and patient-reported psychosocial/quality of life outcomes; objectively measured weight; accelerometer measured PA; and dried blood spots to measure inflammatory/cardiometabolic biomarkers. Qualitative interviews with a subset of participants will take place at 1 and 12 months. The goal of the 12 month ¡Vida! (Life!) program is to achieve 7% weight loss. Following baseline assessments, participants (n=410) will be randomized to ¡Vida! or ¡Vida! + EL. At 1 month, responders (2% weight loss) will continue with their intervention and non-responders (<2% weight loss) will be re-randomized to receive augmented behavioral support (i.e., combinations of EL, individualized health coaching, and delivered groceries). Aim 1) To compare the effectiveness of four adaptive interventions for weight loss in Latina BC survivors, beginning with ¡Vida! or ¡Vida! + EL (Stage 1) followed by augmented behavioral support for 11 months for non-responders (Stage 2). Aim 2) To use a novel data-driven approach to determine whether key individual baseline characteristics moderate the effect of the adaptive interventions on weight loss, and thus lay the groundwork for more personalized adaptive weight loss strategies. Exploratory Aims will i) assess whether intervention engagement moderates the effect of the adaptive interventions on weight loss; ii) compare the effects of adaptive interventions on changes in inflammatory and cardiometabolic biomarkers, diet quality, and PA; iii) quantitatively assess biopsychosocial predictors/mediators of behavior change; and iv) qualitatively assess the participant e...