Metabolic Impact and Compliance of Controlled, Varying, Mediterranean Diets in Pre-Surgical Prostate Cancer Populations (PROVISIONS)

Inclusion Criteria: * Males 18 to 80 years old scheduled to undergo radical prostatectomy as per standard of care. * BMI between 18.5 and 40 * Ability to read, write, speak, and understand English and/or Spanish. * Ability to provide informed consent. * Willingness to consume provided dietary interventions. * Adequate organ and marrow function as assessed by treating clinician(s) which includes: White blood cell count (WBC) ≥2,500/microliter. Absolute neutrophil count (ANC) ≥1,500/microliter. Platelets ≥100,000/microliter. Hemoglobin ≥9 g/dL (transfusions permitted) Total bilirubin ≤1.5 x the institutional upper limit of normal (ULN). For subjects with Gilbert's disease ≤3.0 mg/dL. Aspartate aminotransferase (AST)/Alanine aminotransferase (ALT) ≤2.5 x institutional ULN. Creatinine clearance ≥51 ml/min as defined by Cockcroft-Gault equation. Exclusion Criteria: * Currently consuming a Mediterranean, lower carbohydrate, ketogenic, vegan, vegetarian, high fiber diet (14g fiber \> per 1,000 Calories) and/or any supplements (including herbal), vitamins, minerals, that would interfere with diets being tested in the study as determined by dietitian and/or investigators as these diets are highly restrictive and may impact objectives/outcomes in the trial. * Previous intolerability to fiber-rich diets. * Colitis, Irritable Bowel Syndrome, or other gastrointestinal condition per clinician discretion. * Food allergies or other major dietary restrictions. * Receiving active medical treatment for Type I or Type II diabetes mellitus. * Recent weight loss or gain (both intentional and unintentional) as defined by 5%+ body weight in the last 30 days. * Undergone any type of weight loss surgery. * Any medical contraindications as determined by investigators. * History of diabetic ketoacidosis. * History of Gout. * Patients that are immunosuppressed (transplant history, on immunosuppression, etc.) as per clinician discretion. * Gallbladder removed or plan to remove per clinician evaluation. * Other malignancies actively receiving systemic treatment as per clinician evaluation. * Previous treatment for prostate cancer. * Previous history of pelvic radiation. * Patients with impaired decision-making capacity.