Effects of carbohydrate-modified diets on insulin sensitivity in children and adolescents with overweight/obesity: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND

It remains unclear whether modifying dietary carbohydrate intake affects insulin concentration and sensitivity in children and adolescents with overweight/obesity. This systematic review and meta-analysis aimed to investigate the effects of carbohydrate modifications on insulin-related outcomes in this population.

METHODS

A systematic search in PubMed, Scopus, and Web of Science was conducted up to May 18, 2025, without language restrictions. We included randomized clinical trials that investigated the effects of carbohydrate quantity or quality on insulin markers in children and adolescents with overweight/obesity. The risk of bias and the certainty of evidence were assessed. Random-effects meta-analyses were used to estimate weighted mean differences (WMDs) and 95% confidence intervals (CIs) for each outcome.

RESULTS

Seventeen trials were included. Interventions consisted of low-glycemic index (GI) diets and reduced-carbohydrate diets. The pooled analysis showed that compared to control diets, carbohydrate-modified diets—including both low-GI and reduced-carbohydrate diets—showed no significant effect on insulin concentrations but resulted in a significant improvement in the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) (WMD = -0.43, 95% CI = -0.83, -0.03; I² = 48.8%). Low-GI diets also had no significant effects on fasting insulin and HOMA-IR. However, influence analysis demonstrated a significant decrease in HOMA-IR in the low-GI diets after removing a trial conducted among children with obesity and non-alcoholic fatty liver disease (WMD = -0.49, 95% CI = -0.90, -0.07; I2 = 9.9%). Subgroup analyses also indicated that low-GI diets combined with calorie restriction significantly reduced fasting insulin (WMD = -3.05 µIU/mL, 95% CI: -5.22, -0.87; I² = 0%) and HOMA-IR (WMD = -0.65, 95% CI: -1.13, -0.16; I² = 0%). Additionally, low-GI diets with a balanced macronutrient distribution (46–65% of energy) significantly lowered HOMA-IR (WMD = -0.53, 95% CI: -1.00, -0.06; I² = 22.4%). Reduced-carbohydrate diets had no significant effects on fasting insulin or HOMA-IR compared to control diets.

CONCLUSIONS

This meta-analysis suggests that in children and adolescents with overweight/obesity, improving carbohydrate quality through a low-GI diet may improve insulin sensitivity. The benefits of low-GI diets were particularly observed when they were implemented alongside calorie restriction or when carbohydrates constituted 45–65% of total energy intake. CLINICAL TRIAL NUMBER: Not applicable.