Their results showed that administering P. copri to high-fat diet (HFD) mice increased serum BCAA levels and led to insulin resistance.104 However, when P. copri was given to mice on a high-fiber and low-fat diet, it improved insulin sensitivity by producing succinate, a substrate for intestinal gluconeogenesis.105 These findings further emphasize the complex impact of specific gut microorganisms such as P. copri on insulin sensitivity under different dietary conditions. This evidence concerns the gene INS and Insulin resistance.