investigators evaluated the efficacy of two types of diet with different macronutrients, on prevention or delaying the onset of type 2 diabetes in subjects with either impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). 322 subjects with prediabetes were randomly assigned to high monounsaturated fat diet (n=107), high carbohydrate diet (n=106) or control group (n=109) and followed for 2 years. For calculating daily energy requirement in subjects with BMI≥25 kg/m2 the weight was adjusted with the use of 110 percent of the ideal body weight with no attempt for losing body weight. Control group were encouraged to follow the Food Guide Pyramid and reduce their fat intake to less than 30% of energy consumed and saturated fat to less than 10 percent of total energy. The primary outcome variable was incidence of type 2 diabetes mellitus, diagnosed by the latest American Diabetic Association criteria.