101 children and adolescents with obesity (mean age 12 years) with IR (defined by HOMA-IR > 2.5 or fasting insulin > 15 μU/mL) were randomly assigned to receive either a probiotic mix of Bifidobacterium breve BR03 and B632 (2 × 109 CFU/day) or placebo for 8 weeks, followed by a 4-week washout and crossover.All subjects followed an isocaloric Mediterranean diet and lifestyle recommendations during the trial. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.