High-Fermented Food Intervention Among Locally Advanced Rectal Cancer Patients (The FEED Trial)

Inclusion Criteria for GI Patients: * 18 years of age or older * Diagnosed with locally advanced rectal cancer (Stage II-III) * Will undergo neoadjuvant chemoradiation at Moffitt Cancer Center * Able to pick up FFs once/weekly at Moffitt * Able to speak and read English * Able to consume foods orally * Able to provide informed consent Inclusion Criteria for Thoracic Patients: * 18 years of age or older * Diagnosed with stage II-IV non-small cell lung cancer (NSCLC) * Will undergo Immunotherapy with immune checkpoint inhibitors (+/- chemotherapy or other treatment) at Moffitt Cancer Center * Able to pick up FFs once/weekly at Moffitt * Able to speak and read English * Able to consume foods orally * Able to provide informed consent Exclusion Criteria: * Antibiotic use within 1 month prior to baseline * If currently using probiotics, unwillingness to cease probiotic use * Previous receipt of surgery, immunotherapy, chemotherapy, or radiation for a colon or rectal tumor * Per clinician's discretion, clinician confirmed inflammatory bowel conditions (e.g., ulcerative colitis, Crohn's disease) * Infectious disease diagnosed \<1 month prior to baseline * Already consuming ≥2 servings of fermented foods/day * Previously diagnosed with a mast cell disorder or histamine allergy