The NTU JO-SMART Study

Inclusion Criteria: * Age: 18 to 75 years. * Obesity status: body mass index (BMI) ≥ 27 kg/m², consistent with the obesity definition defined by the Health Promotion Administration, Ministry of Health and Welfare, Taiwan. * Diagnosis of KOA in at least one knee according to the American College of Rheumatology (ACR) criteria, with a Kellgren-Lawrence (KL) grade of 1, 2, or 3. * Symptomatic disease: defined as a WOMAC pain subscale score (range 0-20) greater than 4 at screening. * Sedentary lifestyle: defined as less than 30 minutes of physical activity per week for the past 6 months. * Informed consent: willing and able to provide written informed consent and comply with all longitudinal study procedures. * Comorbid status: participants may be included regardless of a baseline diagnosis of T2D or CKD. Stratified randomization and subgroup analyses will be conducted based on these baseline conditions. Exclusion Criteria: * KL grade 4 KOA in either knee. * Diagnosis of inflammatory arthritis, such as rheumatoid arthritis or psoriatic arthritis. * Knee arthroscopy within the past 3 months or previous surgical history of TKA. * Recent receipt of intra-articular injections (e.g., corticosteroids, hyaluronic acid) within the past 3 months. * Documented history of osteoporotic fracture in hospital or cloud-based medical records. * Type 1 diabetes. * Presence of conditions precluding safe participation in an exercise program, such as unstable cardiovascular disease or severe neurological disorders. * Participation in another interventional clinical trial within the past 3 months. * Engagement in dietary regimens likely to cause significant weight change (e.g., intermittent fasting, such as the 16:8 time-restricted eating) within 1 month prior to trial initiation. * Use of any FDA-approved weight-loss medications (e.g., semaglutide, tirzepatide) within 3 months prior to trial initiation. * History of any form of surgical treatment for weight loss. * Current use of lithium or antipsychotics at a dose equivalent to olanzapine \>20 mg/day. * Pregnant or breastfeeding women, or women of childbearing potential without adequate contraception. * Current malignancy (within the validity period of a catastrophic illness certificate), or any other clinical condition deemed unsuitable for participation by the investigator (investigator discretion). * Inability to use smart devices or telecommunication tools due to severe visual/hearing impairment or lack of internet access.