From the Guidelines
A weight loss of 5-10% of body weight is generally recommended to improve osteoarthritis pain. For example, a person weighing 200 pounds should aim to lose 10-20 pounds to experience meaningful pain reduction. This amount of weight loss has been consistently shown to decrease pain and improve function in patients with knee and hip OA, as supported by the 2019 American College of Rheumatology guideline for the management of osteoarthritis of the hand, hip, and knee 1. Even modest weight loss reduces the mechanical load on weight-bearing joints, with each pound lost resulting in approximately four pounds less pressure on the knees during walking. Weight loss also helps reduce inflammation throughout the body, which contributes to joint pain and cartilage degradation in OA. The benefits are most pronounced when weight loss is combined with exercise, particularly low-impact activities like swimming, cycling, or walking that strengthen muscles around affected joints without causing additional stress. For best results, patients should aim for gradual, sustainable weight loss of 1-2 pounds per week through a combination of calorie reduction and increased physical activity rather than rapid, extreme dieting which is difficult to maintain long-term.
Some key points to consider:
- A dose-response has been noted with regard to the amount of weight loss that will result in symptom or functional improvement in patients with OA, with a loss of ≥5% of body weight associated with changes in clinical and mechanistic outcomes 1.
- Clinically important benefits continue to increase with weight loss of 5–10%, 10–20%, and >20% of body weight 1.
- The efficacy of weight loss for OA symptom management is enhanced by use of a concomitant exercise program 1.
- Sustained weight loss has been shown to benefit pain and, to a lesser extent, function in overweight and obese patients with knee osteoarthritis, with no risk or downside to sustained weight loss and obvious other health benefits 1.
Overall, the evidence suggests that a weight loss of 5-10% of body weight, combined with regular exercise and a healthy lifestyle, can lead to significant improvements in osteoarthritis pain and function, and is a recommended treatment approach for patients with knee and hip OA 1.
From the Research
Weight Loss and Osteoarthritis Pain Improvement
Research studies have investigated the relationship between weight loss and improvement in osteoarthritis (OA) pain. The key findings are:
- A dose-response relationship exists between weight loss and symptom improvement in persons with knee OA 2, 3.
- Greater weight loss results in superior clinical and mechanistic outcomes, with the highest weight loss group (≥20% group) distinguishing itself on all measures compared with the <5% and ≥5% groups 2.
- Long-term weight loss of 10-19.9% of baseline body weight has substantial clinical and mechanistic benefits compared with less weight loss 2.
- A weight loss of ≥7.7% is required to achieve a minimal clinically important improvement in function 3.
- For every 1% weight loss, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) pain, function, and stiffness scores decrease by about 2% points 4.
- A 25% weight reduction from baseline is necessary to obtain a 50% reduction of each subscale of the WOMAC score 4.
Effective Weight Loss Interventions
The following weight loss interventions have been shown to be effective in improving OA symptoms:
- Bariatric surgery 4
- Low-calorie diet and exercise 4
- Intensive weight loss and exercise 4
- Diet-induced weight loss plus exercise 5
- Weight loss diet with reduced fat and carbohydrates 6
Key Takeaways
- Weight loss is a therapeutic intervention that can improve OA symptoms and clinical conditions.
- The amount of weight loss required to improve OA pain varies, but a weight loss of ≥7.7% to 10% is recommended.
- Combining weight loss with exercise is essential to preserve lean body mass and avoid sarcopenia 4.