Association Between Physical Activity and Indicators of Overweight/Obesity and Metabolically Unhealthy Obesity Risk in Children and Adolescents: A Systematic Review of Prospective Epidemiological Studies and Randomized Controlled Trials in Western Countries

This systematic review examined the etiologic association between physical activity (PA) and indicators of childhood overweight/
obesity (OV/OB) and metabolically unhealthy obesity (MUO) risk. Original peer-reviewed English reports published between
January 01, 2013, and June 30, 2024, were retrieved from MEDLINE and Scopus. A total of 106 prospective epidemiological studies and randomized controlled trials (RCTs) conducted in Western countries among 2-to 19-year-olds with ≥12-month follow-up were eligible. Study quality was evaluated through risk of bias (RoB). Regarding OV/OB, epidemiological studies (n = 86, 57% high-RoB) revealed a protective effect of certain accelerometry-measured exposures: moderate-to-vigorous
PA (n = 17/32), vigorous PA (n = 10/15), substituting lower-intensity with higher-intensity PA (n = 7/11), and longitudinally sustaining high PA (n = 3/3). Of the 16 RCTs (31% high-RoB), 10 were successful and most utilized long-term (≥ 1-year) multicomponent PA interventions incorporating behavior change techniques. Random-effects meta-analysis of RCTs revealed a beneficial effect of PA on body mass index (BMI) (n = 5: −0.42 [95% CI: −0.64, −0.21] kg/m2) and BMI z-score (n = 5: −0.09 [95% CI: −0.14, −0.04] SD) change; results were consistent in mixed-effects linear regression models accounting for repeated measurements. PA had no impact on MUO indicators, albeit studies were scarce (n = 4). Promoting PA is a promising strategy against childhood OV/OB. Future research should focus on elucidating its role in MUO prevention.