Clinical Research Directory

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