INS and diabetes mellitus: As also indicated in the section ‘Prevention of diabetes and IR’ in this article, the difference between the two studies could be due to the different mechanisms of action of acarbose (decrease in postprandial blood glucose by delaying carbohydrate absorption) and nateglinide (decrease in postprandial blood glucose by enhancing first-phase insulin secretion) or, more simply, to the fact that in the NAVIGATOR study, nateglinide was actually not able to reduce postprandial blood glucose levels.