Sleep and Its Impact on the Success of Weight Loss Interventions in Adults With Excess Weight: A Systematic Review.

Abstract

To evaluate evidence on the impact of sleep health on weight loss in adults with excess weight undergoing behavioral or surgical weight loss interventions. We conducted a systematic review of randomized controlled trials and quasi-experimental studies including adults aged ≥ 18 years with BMI ≥ 25 kg/m². MEDLINE, Embase, and CENTRAL were searched from inception to September 2025. Screening, data extraction, and risk of bias assessment were performed in duplicate. Sleep was examined either as an exposure or as an intervention component. A narrative synthesis was conducted using the RU-SATED framework and stratified by sleep exposure versus sleep intervention studies. Thirty studies (13 randomized controlled trials and 17 quasi-experimental studies; 10,944 participants from 13 countries) were included. Evidence was mixed across sleep dimensions. In behavioral weight loss interventions, sleep manipulation studies suggested that sleep restriction reduced fat loss, whereas observational studies reported inconsistent associations between sleep duration and weight loss. Limited evidence suggested that greater sleep satisfaction and higher sleep efficiency may support weight loss, with approximately half of the studies reporting positive associations. Evidence for sleep regularity, timing, and alertness was sparse and inconsistent because of the small number of studies and methodological heterogeneity. Sleep satisfaction and sleep efficiency may support weight loss in behavioral interventions, whereas sleep duration shows inconsistent associations and sleep restriction may impair fat loss. Evidence for sleep regularity, timing, and alertness remains limited. High-quality experimental studies are needed to clarify the causal role of sleep health in weight loss outcomes.