The overall goal of the proposed research is to provide the experimental evidence for the later alternative by showing that the modest weight gain that takes place in association with effective rosiglitazone treatment of hyperglycemic patients with type 2 DM is primarily due to its therapeutic efficacy. More specifically, by decreasing the caloric intake in proportion to a decrease in urinary glucose loss associated with improved glycemic control, we will be able to prevent significant weight gain following Rosiglitazone treatment. In order to provide an optimal dietary modification that can be universally applied to TZD-treated patients in clinical practice, we will have a group with a fixed amount of caloric restriction per day. It will be the first randomized controlled trial of a potential strategy for prevention of weight gain associated with thiazolidinediones.