Background: Changes in body weight and composition (fat and lean mass) are prominent side effects from cancer treatment. Nutrition and exercise interventions are both key strategies to protect against these adverse effects, however their impact when combined have not been comprehensively reviewed in adults with cancer.
Objective: This systematic review and meta-analysis aims to assess the effects of combined nutrition and exercise interventions on body weight and composition in adults with cancer.
Data sources: Four databases were searched until January 2021. Eligible studies included combined nutrition and exercise randomised controlled trials (RCTs), detailing the nutrition and exercise prescription, and reporting body weight and composition outcomes.
Data extraction: Risk of bias was assessed through the Cochrane Collaboration tool. The number of participants, mean values and standard deviations of the outcome variables were extracted. Mean differences (MD) were pooled using random-effects models. Predetermined sub-group analyses included cancer type, intervention intent, exercise modality, and use of behaviour change theory.
Results: Twenty-three RCTs were included in this review. Nutrition plus exercise interventions significantly reduced body weight (MD -2.13 kg, 95% confidence interval [CI] -3.07, -1.19) and fat mass (MD –2.06 kg, 95%CI -3.02, -1.09), and lean mass (MD -0.42, 95%CI -0.82, -0.04). Subgroup analyses in women with breast cancer showed that weight loss interventions, and interventions incorporating behaviour change theory, significantly reduced body weight and fat mass, but also reduced lean mass. Interventions aiming to maintain body weight showed no changes in body weight as intended.
Conclusion: Combined nutrition and exercise interventions successfully reduce body weight and fat mass in adults with cancer but also reduced lean mass. In contrast, weight loss focused interventions were associated with reduced lean mass.