Dietary Interventions Based on the Mediterranean Diet to Treat Obesity in Children and Adolescents: A Systematic Review with Meta-analysis and Meta-regressions

Context: Overweight and obesity among children and adolescents are increasing globally, requiring effective treatment strategies to mitigate future health risks. Objective: This systematic review and meta-analysis with meta-regressions evaluated the impact of Mediterranean diet (MD)-based dietary interventions, with or without physical activity (PA), on anthropometric parameters and adherence to the MD in children and adolescents with overweight or obesity. Data sources: Scopus, PubMed/Medline, ISI/Web of Science, Embase, and Cochrane Central Register of Controlled Trials were searched as data sources for intervention studies, either designed as randomized controlled trials (RCTs) or non-RCTs. Primary outcomes were changes in body weight and body mass index (BMI); secondary outcomes included body fat, waist circumference, and adherence to the MD. Data extraction: Eighteen studies involving 1539 participants aged 2-18 years were analyzed. Nine and 2 of the included studies were RCTs and randomized trials without a control group, respectively, whereas the others were non-RCT studies without a control group. Four exclusively presented an MD-based dietary intervention without a PA addition. Data analysis: Mediterranean diet-based interventions improved BMI (effect size [ES] = 0.34; 95% CI, 0.13-0.56) and body fat (ES = 0.64; 95% CI, 0.19-1.08). Waist circumference changes were smaller but significant (ES = 0.22; 95% CI, 0.06-0.38). Changes in body weight (ES = 0.22; 95% CI, -0.04 to 0.48) were not significant. Combining these outcomes, the overall ES was computed at 0.42 (95% CI, 0.14-0.70). Adherence to the MD significantly increased in all studies reporting it. Interventions combining an MD and PA showed stronger effects compared with an MD alone. Conclusion: Mediterranean diet-based interventions, particularly with PA, significantly improve BMI and body fat in children and adolescents with obesity, offering a promising strategy for early-life obesity management. However, high study heterogeneity and nonsignificant results in some outcomes underscore the need for more robust research. Systematic review registration: PROSPERO registration no. CRD42020179868.