Bariatric surgery offers substantial and sustained weight loss for most patients, with diabetes improvement or remission and also reduction in weight-related comorbidities in patients with a BMI of 35 kg/m² or more. The same benefits have not yet been established for patients with a BMI of less than 35 kg/m 2 , since there is still limited evidence based in very few studies investigating less than one hundred patients with class I obesity. Moreover, in larger studies involving patients with higher baseline BMI such as the Swedish Obese Subjects Study, the degree of weight loss has been significantly associated with glycemic improvement, independently of the surgical procedure when stratified by weight. In spite of this, delegates of International Bariatric Surgery and Diabetes Organizations during the 2 nd Diabetes Surgery Summit in London recently approved a joint statement where surgery should be considered (consider should not have the same strength of a recommendation) for patients with type 2 diabetes and BMI between 30.0 and 34.9 kg/m 2 if hyperglycemia is inadequately controlled despite optimal treatment with either oral or injectable medications, including insulin; and these BMI thresholds should be reduced by 2.5 kg/m 2 for Asian patients (in spite of short duration of diabetes, good glycemic control and absence of insulin therapy be preoperative predictive factors of diabetes remission) (1). Recently, some cardiovascular safety trials with diabetes medications have demonstrated that these drugs offer cardiovascular protection (2); more data on hard outcomes are required to better assess not only the efficacy, but mainly the safety in very large series before endorsing the widespread indication of bariatric surgery in the subpopulation of type 2 diabetics with a BMI below 35 kg/m 2 . A significant proportion of individuals undergoing bariatric surgery experiment weight regain, residual diabetes or diabetes relapse (i.e., around one third of initial remitters over five years do not achieve remission or have diabetes recurrence), requiring to cope with the residual diabetes and emerging obesity (2,3) and also to deal with lifelong nutritional deficiencies and other potential long-term complications, such as vomiting, adhesions, strictures, gallstones, hernias, drinking problems, and small-bowel obstruction (4,5). In the scope under discussion, it is essential that the diagnosis of diabetes in patients undergoing bariatric surgery be reliable and safe.In this issue of Archives of Endocrinology and Metabolism, a study examined the adverse effects of the oral glucose tolerance test (OGTT) in 128 patients who underwent bariatric surgery, of which more than 90% were women and nearly 30% pregnant. Around two thirds of patients experienced one to four or more limiting adverse effects such as nausea, dizziness, weakness, diarrhea, tachycardia, sweating or hypoglycemia during the test. The main reasons for ordering an OGTT were presence of symptoms suggestive of hypoglycemia, pregnancy, type 2 diabetes prior to su...