PBMCs from children with overweight/obesity exhibit increased mitochondrial respiration, regardless of insulin sensitivity; however, the metabolism of PBMCs from insulin‐resistant children with overweight/obesity is shifted even more towards more mitochondrial respiration and away from glycolysis when compared to PBMCs from insulin‐sensitive overweight/obese children. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.