Obesity, a globally increasing factor and its impact on healthcare needs to be focused. Geriatric subjects with obesity and osteoarthritis knee changes influences level of dependency, and decrease quality of life. Aims and objectives of this study was to analyse the role of weight reduction exercises, dietary regulations on obesity and physical function, to evaluate the efficacy of exercises based on biomechanical causes and changes that follows. Materials & Methodology: With ethical committee approval and subjects concern, weight reduction exercises with dietary advice along with exercises based on the altered biomechanics in a obese subject with osteoarthritis knee were analyzed in this original experimental case study design, for a period of 3 months from February 2017 to April 2017 at TamilNadu, India. He was treated with non pharmacological means, using specific exercises with weekly twice frequency at 50% - 70% of his M.H.R, Results: statistically highly significant (P<.001) with womac score on physical functioning functional betterment and significant (P<.05) indicating reduction in obesity of this subject with osteoarthritis knee following treatment with =. Conclusions: Apart from routine exercises in subjects with osteoarthritis knee, weight reduction means and treating the underlying cause for altered mechanics of movements with specific exercises makes a huge improvement in therapy outcome were the main outcome of this original research study.