INS and obesity due to melanocortin 4 receptor deficiency: The beneficial effects of butyrate administration on glucose metabolism were consistent with previous data.27 Butyrate supplementation improved insulin sensitivity, limiting insulin resistance and hyperinsulinemia in animals28,29 and in lean humans.30 Butyrate supplementation decreased HOMA-IR levels in adults with diabetes.31 In line with these data,27,28,29,30,31 we found that butyrate supplementation decreased HOMA-IR and fasting insulin levels in children with obesity.