Dr Francesco Rubino of Weill Cornell Medical College presented results of studies showing that NICE's BMI cut-off of 35kg/m2 for patients with diabetes to qualify for bariatric surgery was 'inappropriate'.
Patients with a BMI less than this cut-off have been found to achieve improvement or remission of type-2 diabetes with surgery, he said.
The antidiabetic effect observed in studies of bariatric operations could be explained by their effects on food intake and body weight alone, he argued.
Bariatric procedures could be considered to treat uncontrolled diabetes in patients with a BMI of 30-35kg/m2, he said.
Professor Peter Havel, of the University of California, suggested that more research was needed into the mechanisms by which bariatric surgery improves patient outcomes. This could allow the development of non-surgical options with similar efficacy, he said.