One of the most amazing findings in bariatric surgery is the resolution of most comorbidities associated with obesity, especially type 2 Diabetes mellitus (T2DM), with remission rates in 84 to 98.9% of the patients. The evidence shows that such remission could not be explained only by the weight loss. There are several theories for explaining the normalization of glycemia as an increase in incretins production (GLP-1) from the distal gut, phenomena related to the exclusion of the nutrients passing through duodenum, hormones like ghreline and other effects not yet descript. A field under crescent investigation is the development of surgical procedures in the management of T2DM in non obese patients.