To examine the effects of insulin on gluconeogenesis suppression as well as lipogenesis promotion in the livers of NAFLD patients, we selected key insulin signaling molecules, IRS-1 and IRS-2, and key enzymes for gluconeogenesis, PEPCK and G6Pase, for glycolysis, GCK, and for lipogenesis, FAS. This evidence concerns the gene FAS and metabolic dysfunction-associated steatotic liver disease.