Rheumatoid arthritis is a chronic disease characterised by synovial joint inflammation and erosion. However, it is also a systemic disease featuring alterations in protein and energy metabolism with consequent accelerated loss of skeletal mus cle. This syndrome, called rheumatoid cachexia, affects >50% of patients and is associated with disability and increased risk of death. Therefore, interventions aimed at stimulating musc le growth or preventing hypercatabolism have the potential to improve the long-term outcome of rheumatoid arthritis. In this th esis the results of three different controlled clinical trials are presented. In the first study, 10 rheumatoid arthritis patients underwent a high intensity progressive resistance training program. Compared to 10 age and sex matched patients who did not exercise, the subjects in the training group had a significant increase in muscle mass and strength and a reduc tion in dis ability w ith no exacerbation of di sease activity. In the second study, 40 rhe umatoid arthritis patients were randomly assigned to dietary supplementation with a mixture of anabolic amino acids (P-hydroxy-~-methylbutyrate, glutamine and arginine) or a nitrogen-balanced (7 .19 g/day) mixture of other " metabolically in ert" amino acids (placebo). Contrary to our hypothes is, subjects in both groups experienced the same s ignificant in c rease in total body protein and some improvements in physical function. As habitual protein intake was normal in these patients, thes e res ults suggest that rheumatoid arthritis increases nitrogen requirements . The last s tudy was a randomised controlled trial of anti-tumor necrosis factor therapy with etanercept (n = 12) compared to standard therapy with methotrexate (n = 12). Although both agents were equally effective in preventing muscle wasting in patients with early rheumatoid arthritis, etanercept improved the anabolic response to overfeeding in those patients who gained weight over the s ix month fo llow-up period. In conclus ion, rheumatoid cachexia is reversible and anabolic/ anticatabolic interventions should be studied further and implemented in clinical practice.