The gastric bypass was originally developed as a treatment for obesity, but doctors have been amazed at how quickly it benefits people with type 2 diabetes sometimes within a matter of days or even hours. Some surgeons and learned societies have stopped calling the procedure obesity surgery and instead speak of metabolic surgery - referring to the fact that it can treat metabolic conditions such as diabetes. The radical idea now is that diabetes could be treated more routinely with this type of surgery. The key question is how overweight people have to be in order to qualify. At the moment the procedure is normally offered only to those with a body mass index of 35 or more (between 18.5 and 25 is considered normal), on the grounds that only at that weight will the clinical improvement outweigh the risks of surgery. But some doctors are lowering the BM I cut-off to 30 for people with diabetes. Some in South America have raised eyebrows by operating on diabetics with a BMI as low as 25. 'The excel lent results early after surgery before significant weight loss has led us to extend the surgical approach to people in whom significant weight loss is not required;' says Bruno Geloneze, an endocrinologist at the State University of (ampinas in Brazil. In May his team published a study of 12 diabetics whose BMI was between 25 and 30 - in other words, they were not obese, merely overweight. All experienced improvements in their symptoms after a bypass, and without unexpected complications. But only larger randomised trials will reveal if the benefits outweigh the risks. Francesco Rubino, a metabolic surgeon at (ornell University-New York Presbyterian Hospital, doesn't think surgery should automatically be offered to everyone with type 2 diabetes, but he agrees that using a cut-off for BMI is too crude a measure. "It should be based on more comprehensive considerations than BMI alone," he says.