The aim of the study is to evaluate the effect of experimental (vegetarian) diet compared to conventional diet with similar caloric restriction on insulin resistance, body weight and body composition in type 2 diabetic patients after 3 month diet program and additional 3 month diet program combined with intensive exercise.

Hypothesis: Greater improvement in insulin resistance, greater weight loss without compromising the body composition (subjects will lose fat preferentially to lean body mass) and differences in the fatty tissue metabolism will be found in the experimental (vegetarian) group compared to the control (conventional diet) group despite the similar advise on caloric restriction in both diets. The differences between the two groups will increase after an intensive physical exercise program.

Open randomized study. Individuals with type 2 diabetes (n=60) will be recruited through newspaper advertisements and through advertisements in the hospital. They will be randomly assigned to a low-fat vegetarian diet or a diet following the guidelines of the Study Group on Diabetes and Nutrition of the European Association for the Study of Diabetes (DNSG) (21) with similar caloric restriction (-500 kcal/d). The participants will be followed for 12 weeks and then for another 12 weeks with the addition of intensive physical exercise. All meals during the 6 months will be provided.

Inclusion Criteria:

1. Individuals with type 2 diabetes as defined by the criteria of the American Diabetes Association and recognized by WHO, Expert Committee on the Diagnosis and Classification of Diabetes Mellitus (19,20)
2. Concurrent T2 DM therapy: The use of oral hypoglycemic medication stable for the last 3 months
3. HbA1c ≥ 4 and ≤ 9.0 % (IFCC) ~ ≥ 6.0 and ≤ 11 % (DCCT)
4. Men and women who are 30 to 70 years of age
5. Body Mass Index (kg/m2) between 25 and 53
6. Informed Consent: a signed and dated written consent obtained from the subject before any procedures are performed
7. Willing to change dietary habits and to follow the prescribed diet and exercise program

Exclusion Criteria:

1. Current alcohol or drug abuse
2. Pregnancy, lactating
3. Unstable medical status
4. Diagnosis of Type 1 diabetes mellitus
5. Significant weight gain or loss (defined as ≥ 10% of total body weight) within the past 3 months prior to screening.
6. Pacemaker or metal in the body.