Effects of Nonnutritive Sweeteners on the BMI of Children and Adolescents: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Prospective Cohort Studies

The effect of nonnutritive sweeteners (NNSs) on the body mass index [BMI (in kg/m²)] of children and adolescents remains unclear despite rising consumption. Detailed systematic evaluations are warranted. We aimed to summarize evidence on NNS consumption and BMI sex- and age-specific absolute changes (kg/m²) in pediatric populations, by NNS type, study design, duration, analysis type, conflicts of interest (COI), geographical region, age, sex, and baseline BMI. We searched randomized controlled trials (RCTs) and prospective cohort studies in children (2-9 y), adolescents (10-24 y), and young adults (20-24 y). Pooled estimates derived from random-effects meta-analysis for BMI changes, and the evidence quality was evaluated overall and by subgroup. From 2789 results, we included 4 RCTs [n = 1372; mean follow-up = 42.6 wk (standard deviation = 18.4); 2 (50%) with COI], and 8 prospective cohort studies [n = 35,340; median follow-up 2.5 y (interquartile range = 1.7-6.3), 2 (25%) with COI]. No identified studies evaluated NNS in food, NNS beverages compared with water, or participants aged 20-24 y. Random allocation to NNS beverages (25-2400 mg/d, from beverages) showed less BMI gain [mean difference = -0.114 kg/m² (95% confidence interval [CI]: -0.207, -0.021); I² = 87.02%] compared with sugar-sweetened beverages (SSBs). Stratified estimates resulted in less BMI gain in adolescents, participants with baseline obesity, consumers of mixed NNS, longer trials, and trials without COI. Pooled estimates from prospective cohorts showed a nonsignificant association between NNS beverages and BMI gain [0.05 kg/m² (95% CI: -0.03, 0.13); I² = 75.06%; per daily 355 mL serving]. Stratified estimates remained consistent. Removing studies with COI attenuated estimates. Evidence had low to moderate quality. In summary, pooled results from RCTs comparing NNS beverages compared with SSBs showed less BMI gain in adolescents with obesity. Meta-analyses of long-term cohort studies did not display a significant association between NNS beverages and BMI changes. This trial was registered at PROSPERO as CRD42022352284.