BACKGROUND: Nutritional supplementation and resistance training are broadly recommended as part of the treatment of sarcopenia, but studies that have evaluated interventions in inflammatory bowel disease patients with sarcopenia are lacking. The aim of this study was to evaluate the effects of nutritional supplementation and resistance training for improving height-adjusted appendicular skeletal muscle mass (ASM/H2) and medical indices in patients with inflammatory bowel disease. METHODS: This randomized, double-blind, placebo-controlled trial of forty-five participants was performed at Huadong Hospital Affiliated to Fudan University in Shanghai from September 2020 to June 2021. Eligible participants were randomly assigned to receive whey protein (10 g/d) or placebo (10 g/d) for 8 weeks while completing a resistance training program (3 times a week). Data such as ASM/H2 and other medical indices were collected at baseline and at 4 and 8 weeks of intervention. RESULTS: Fifteen participants were allocated to the resistance training and whey protein (RT+WP) group, and thirteen participants were allocated to the resistance training and placebo (RT+placebo) group. The ASM/H2 significantly increased in the RT+WP group after 4 and 8 weeks of intervention, and the ASM/H2 of the RT+WP group was significantly higher than that of the RT+placebo group after 4 and 8 weeks of intervention (F = 1.092, P = .035). Both interventions significantly increased albumin (F = 7.214, P = .003). Hemoglobin and creatinine significantly increased in the RT+WP group (F = 3.592, P = .035; F = 3.922, P = .033, respectively). In addition, a significant group × time interaction was not observed for body mass index, 5-time chair stand test time, 3-metre walk speed, grip strength, waist circumference, hip circumference, or waist-to-hip ratio (P > .05). CONCLUSIONS: Nutritional supplementation may be effective in improving sarcopenia, as well as many other physiological indicators during resistance training.