Type 2 diabetes mellitus (T2DM) has become an epidemic. Compared to Western countries, Asian T2DM occurs in patients with a lower body mass index, due to central obesity and decreased pancreatic β-cell function. The efficacy of surgical treatment such as sleeve gastrectomy, adjustable gastric banding, and gastric bypass in obese patients with T2DM has been demonstrated by numerous studies from Western countries. However, current evidence on surgical treatment for non-morbidly obese diabetic patients is lacking. Recently, several preliminary studies demonstrated the remission of hyperglycemia in non-obese T2DM patients by surgical bypass. One possible hypothesis is the foregut theory an inactivation of the anti-incretin system through the exclusion of the foregut from ingested food, and the other is the hindgut theory, in which rapid hindgut exposure prompts the delivery of undigested food to the terminal ileum and promotes the activation of incretin system such as glucagon-like peptide-1 The following teaching points and direction of future study are recommended: understanding the mechanism of diabetic remission through surgical procedure, defining the surgical indications for T2DM, predicting the possible complications and disadvantages of surgical treatment, and understanding the peculiarity of each surgical procedure. The remission of hyperglycemia in non-obese T2DM patients could possibly be achieved by surgical intervention. Although long-term follow-up data and verification of its exact mechanisms are required, early operative outcomes were satisfactory in terms of glycemic control and the safety of the procedure.