Insulin resistance refers to the reduced sensitivity to insulin action in the target organs of insulin action (mainly liver, muscle and adipose tissue).The main causes of insulin resistance have not yet been elucidated, and there are currently two main arguments: lipid overload and inflammation. Adipocyte enlargement inhibits insulin signaling by increasing circulating levels of free fatty acids (FFA) and their metabolites, as well as by depositing them in non-adipocytes (mainly myocytes, hepatocytes, and pancreatic islet β-cells); Enlarged adipocytes attract macrophages, which secrete inflammatory signaling molecules (e.g., TNF-α, resistin, IL-6, etc.) that block insulin signaling in skeletal muscle via Jun amino-terminal kinase (JNK); the two cross over each other and complement each other. In particular, central obesity is closely related to insulin resistance and the development of T2DM, so it is important to pay attention to the appropriate adjustment of lifestyle habits for prevention. Seek prompt medical attention if you feel unwell.