 It is now well established that the 21st century will be characterized by a global epidemic of Type 2 diabetes. The principal aim of the CANOE study is to determine whether individuals with the pre-diabetes condition impaired glucose tolerance can be prevented from progressing to diabetes with a healthy living lifestyle intervention and an insulin sensitizing medication. Individuals who have impaired glucose tolerance IGT determined during an oral glucose tolerance test will be eligible to participate in this study. All participants will receive a lifestyle dietary and exercise intervention program. Half of the participants will be randomly assigned to an insulin sensitizing medication rosiglitazonemetformin which is commonly used to treat Type 2 diabetes. The primary outcome for this study is the development of diabetes. The study is expected to last a total of five years. 