What are the most effective exercise, physical activity and dietary interventions to improve body composition in women diagnosed with or at high-risk of breast cancer? A systematic review and network meta-analysis.

Background: Obesity has been recognized as a risk factor in the development and recurrence of breast cancer and is also associated with poor prognostic outcomes. This systematic review and network meta-analysis aimed to identify the most effective exercise, physical activity, and dietary interventions to reduce fat mass, body fat percentage and body weight as well as potentially increase lean mass in women diagnosed with or at high risk of breast cancer.

Methods: A systematic search of databases was performed up to May 2022. Eligible randomized controlled trials examined the effects of exercise, physical activity and/or dietary interventions on fat mass and lean mass in women diagnosed with or at high risk of breast cancer. A random-effects network meta-analysis was conducted to determine the effects of different interventions across outcomes when sufficient studies were available.

Results: Eighty-four studies (n = 6428) were included in this review. Caloric restriction and combined exercise + caloric restriction significantly reduced fat mass (range, -3.9 to -3.7 kg) and body weight (range, -5.3 to -4.7 kg), whereas physical activity + caloric restriction significantly reduced body fat percentage (-2.4%; 95% confidence interval [CI], -3.4% to -13%) and body mass index (-2.2 kg × m ; 95% CI, -3.0 to -1.4 kg × m ) in breast cancer patients. Resistance exercise was the most effective intervention to increase lean mass (0.7 kg; 95% CI, 0.5-1.0 kg) in breast cancer patients.

Conclusion: Multimodal exercise and diet programs were the most effective interventions to reduce fat mass, body fat percentage, and body weight and increase and/or preserve lean mass.