Inclusion Criteria:  Age ≥ 55 years Fulfills the American College of Rheumatology Criteria for symptomatic and radiographic osteoarthritis of the knee Body mass index > 30.0 kg/m2 Baseline (Month 0) WOMAC pain subscale score ≥ 40  Exclusion Criteria:  Dementia, neurological disease, cancer, cardiovascular disease, renal disease, liver disease, or other serious medical conditions limiting ability to participate in the programs. Factors known or likely to impact the intestinal microbiota or known to be associated with microbial translocation: antibiotic or probiotic use within the previous 4 weeks, gastrointestinal morbidity (irritable bowel syndrome, inflammatory bowel disease, history of gastrointestinal cancer or surgical resection, or acute, severe gastrointestinal symptoms requiring medical attention), opportunistic infection, and evidence of hepatitis B or C virus infection