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#300 No Gain, No Pain? – What is the effect of diet-induced weight loss on osteoarthritis-related knee pain?

Will diet-induced weight loss reduce osteoarthritic knee pain in overweight and obese adults?

Observational data suggests that obesity may be a risk factor for developing osteoarthritis, however trials reporting diet-induced weight loss alone (example 5% weight loss) demonstrate limited, likely clinically insignificant improvements in osteoarthritic pain (~5 points on 100-point pain scale) compared to control. Studies are limited by the small magnitude of weight loss.

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  • Highest quality systematic review and meta-analysis, 4 randomized, controlled trials (RCTs), 676 patients, BMI~35.1
    • Mean diet induced weight loss 8% (8.5kg) versus 3% (2.7kg) control.
    • Statistical improvement in pain scales with diet-induced weight loss: Effect size=0.33.
      • Equivalent to ~5 points on 100-point scale.2
        • Improvement ranged from 2-9 out of 100.
      • Minimal clinically detectable difference 9-10.3,4
  • Additional systematic review and meta-analysis, diet induced weight loss versus control, BMI~34.5
    • Change in pain scales from diet-induced weight loss alone not statistically different from control (5 RCTs, 616 patients).
    • Diet-induced weight loss + exercise resulted in statistical improvement in pain scales over control, 3 RCTs, 264 patients.
      • Effect size=0.37.
      • Improvement on 100-point pain scale ranged from 2-11.
  • Limitations: Relevant studies excluded.
  • Meta-analysis of 22 cohort studies found that patients with BMI >30 were twice as likely to have knee osteoarthritis (OR 2.66).
  • One RCT, mean BMI ~35, reported that intensive diet and exercise interventions prevented development of knee pain at one year (secondary analysis).7
  • Guidelines recommend education and exercise programs with or without dietary weight management for knee osteoarthritis, citing insufficient evidence for dietary management alone.8
  • Exercise results in 47% of osteoarthritis patients achieving a 30% reduction in pain compared to 21% in control.9
  • No RCTs examine more substantial forms of weight loss (i.e. bariatric surgery) and knee pain.
    • Observational data suggests surgically induced weight loss of ~15-35% resulted in ~75% of people experiencing some benefit in knee pain.10
  • There is no one size fits all diet. If weight loss is desired, patients should choose a diet they can adhere to.11

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  • Christina Korownyk MD CCFP
  • Logan Sept

1. Xi Chu IJ, Lim AY, Ng CL, et al. Obesity Reviews. 2018; 19(11):1597-607.

2. Christensen R, Astrup A, Bliddal H. Osteoarthritis Cartilage 2005; 13(1): 20–27.

3. Ehrich EW, Davies GM, Watson DJ, et al. J Rheum. 2000; 27(11):2635-41.

4. Bellamy N, Hochberg M, Tubach F, et al. Arthritis Care Res (Hoboken). 2015 Jul;67(7):972-80.

5. Hall M, Castelein B, Wittoek R, et al. Semin Arthritis Rheum. 2019; 48(5):765-777.

6. Silverwood V, Blagojevic-Bucknall M, Jinks C, et al. Osteoarth Cartil. 2015; 23(4):507–515.

7. White DK, Neogi T, Rejeski WJ, et al. Arth Care Res (Hoboken). 2015; 67(7):965-71.

8. Bannuru RR, Osani MC, Vaysbrot EE, et al. Osteoarthritis Cartilage. 2019 Nov; 27(11):1578-1589.

9. Ton J, Perry D, Thomas B, et al. Can Fam Physician. 2020; 66(3):e89-e98.

10. Groen VA, van de Graaf VA, Scholtes VAB, et al. Obes Rev. 2015; 16(2):161–70.

11. Ting R, Allan GM, Lindblad AJ. Tools for Practice #220 online publication. Available at: Accessed September 27, 2021.

Authors do not have any conflicts of interest to declare.