Sixty-one obese patients with hip osteoarthritis were randomized to receive 3 months of a fiber-enriched high carbohydrate diet (n=36) or control (free diet; n=25) for the reduction of body weight, and improvement of pain and hip function prior to total hip arthroplasty. Outcomes of interest included weight, body mass index (BMI), cholesterol, Oxford Hip Scores (OHS), Hip Disabilities and Osteoarthritis Outcomes Score (HOOS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). No significant differences in weight, BMI, or OHS scores were observed between the diet and control groups. However, cholesterol levels and WOMAC scores were significantly in favour of the diet group at follow up. HOOS scores at both baseline and follow up were significantly different between the two groups.