Weight Loss Interventions to Reduce Cancer Progression in Prostate Cancer Patients Under Active Surveillance

PRIMARY OBJECTIVES: I. Develop two evidence-based behavioral weight loss intervention programs (IF and CER) with a goal to cause weight loss in prostate cancer (PCa) patients on active surveillance (AS). II. Determine the initial comparative effectiveness of two intervention programs (IF and CER) on weight loss and PCa progression outcomes. SECONDARY OBJECTIVE: I. Compare the effects of the interventions on biomarkers underlying obesity and PCa to provide mechanistic insights and potential surrogate biomarkers for PCa prognosis. OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients undergo the CER intervention consisting of remote lessons containing information and behavioral strategies about weight loss, session with study interventionist to review lessons, and self-monitoring of body weight, physical activity and dietary intake. Patients also undergo collection of blood samples throughout the trial. ARM II: Patients undergo IF intervention consisting of remote lesson containing information and behavioral strategies about fasting, session with study interventionist to review lessons, and self-monitoring of fasting. Patients will undergo fasting 2 days per week and eat according to the National Cancer Institute (NCI) guidelines the remaining 5 days. Patients also undergo collection of blood samples throughout the trial.