This clinical trial evaluates remotely delivered, community-aligned weight loss interventions in Latina breast cancer survivors. Breast cancer is the second leading cause of cancer death among women in the US. There are population differences in breast cancer mortality, based on specific risk factors, including obesity. Cancer is the leading cause of death among Latinos, and among Latinas, breast cancer is the leading cause of cancer death. An estimated 80% of Latinas in the United States have overweight/obesity, which is associated with poorer breast cancer outcomes. However, few, if any, effective interventions exist to promote and maintain weight loss in Latina breast cancer survivors. The development of an adaptive program that provides survivors with the support they need, as opposed to what is typically available, to improve breast cancer survivorship.

OUTLINE: This sequential multiple assignment randomized trial (SMART) will test four different community-aligned 12-month adaptive weight loss interventions.

BASELINE: Participants receive written instructions and website link to complete surveys along with supportive materials including a measuring tape, Bluetooth-enabled scale, and may receive an Actigraph accelerometer to be worn for 7 days at baseline. Participants also undergo blood sample collection at baseline.

STAGE ONE: Eligible participants from the baseline run-in are randomized to participate in Stage One. In Stage One, participants are randomized to one of two groups: ¡Vida! or ¡Vida! Plus.

STAGE TWO: Percent weight loss is measured at week 8. Women who lose ≥2% of their body weight at week 8 will be considered "Responders" and will continue with their original randomization assignment in Stage Two.

Women in the Stage One ¡Vida! group who lose <2% of their body weight will be re-randomized in Stage Two to receive either ¡Vida! Plus or ¡Vida! Plus + health coaching (HC). Women in the Stage One ¡Vida! Plus group who lose <2% of their body weight will be re-randomized in Stage Two to receive either ¡Vida! Plus + HC or ¡Vida! Plus + HC + mailed toolkits (MT).

Inclusion Criteria:

• Biologically female
• Age >= 18 years
• Self-identifies Hispanic/Latina
• Able to read and write in Spanish and/or English
• Previous diagnosis of stage I-III BC within the past 5 years
• No evidence of current, recurrent, or metastatic disease
• 60 days post treatment, including chemotherapy, radiation therapy, and cancer-related surgery (NOTE: current allowed therapies include endocrine therapy, CDK4/6 inhibitors (e.g. palbociclib,ribociclib, abemaciclib), HER2-directed therapies (e.g., trastuzumab, neratinib), and monoclonal antibodies (e.g., pertuzumab, pembrolizumab); surgery for breast reconstruction is allowed during the trial)
• Body mass index (BMI) >= 27 kg/m^2 initially assessed via self-reported height and weight and confirmed prior to randomization via a tape measure and Bluetooth-enabled scale
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1
• Willingness to participate in all study activities
• Access to phone for study contacts
• Access to internet to participate in the online program and to be able to sync study devices
• Successful completion of at-home baseline assessments prior to randomization

Exclusion Criteria:

• Body mass index (BMI) < 27 kg/m^2 at time of baseline data collection
• Diabetic with current use of insulin or sulfonylurea medications (note: current use of metformin is allowed)
• Use of glucagon-like peptide-1 (GLP1) receptor agonist medications reported at baseline
• Current use of cytotoxic chemotherapy medications (e.g., capecitabine) or drug-antibody conjugates (e.g., trastuzumab emtansine [T-DM1], trastuzumab deruxtecan [T-DXd])
• Major comorbidities or physical limitations that would preclude from healthy weight loss, reducing energy intake or engaging in PA
• Pregnant, breastfeeding, or planning to become pregnant during the study period
• Use of exogenous hormones for gender affirmation
• For stool sample collection only: Self-reported use of oral or intravenous antibiotics, antifungals, or anti-parasitics during the past 6 months
• For stool sample collection only: Presence of self-reported ileostomy or colostomy
• For stool sample collection only: Presence of self-reported inflammatory bowel diseases (e.g., Crohn's disease, ulcerative colitis)
• Anticipated major surgical procedure (e.g., hysterectomy) within 3 months after study registration. Breast reconstruction is allowed during study participation.
• Concurrent enrollment in another weight loss or physical activity trial