40 women with PCOS followed one of two isocaloric weight maintenance diets (isocaloric diet with 3 meals or isocaloric diet with 6 meals), tailored to individual energy needs, with the same macronutrient composition (40% carbohydrates, 25% protein, 35% fat). The energy and carbohydrate contribution for the 3 meals' diet was 20% at breakfast, 50% at lunch, 30% at dinner, whereas for the 6 meals' diet was 20% at breakfast, 10% at morning snack, 30% at lunch, 10% at afternoon snack, 20% at dinner, 10% at before bedtime snack. Each intervention lasted 12 weeks and there was no wash out period.

35 individuals with Impaired Glucose Tolerance (IGT) followed one of two isocaloric weight maintenance diets (isocaloric diet with 3 meals or isocaloric diet with 6 meals), tailored to individual energy needs, with the same macronutrient composition (45% carbohydrates, 20% protein, 35% fat). The energy and carbohydrate contribution for the 3 meals' diet was 20% at breakfast, 50% at lunch, 30% at dinner, whereas for the 6 meals' diet was 20% at breakfast, 10% at morning snack, 30% at lunch, 10% at afternoon snack, 20% at dinner, 10% at before bedtime snack. Each intervention lasted 12 weeks and there was no wash out period.

12 individuals diagnosed with type 2 diabetes followed one of two isocaloric weight maintenance diets (isocaloric diet with 3 meals or isocaloric diet with 6 meals), tailored to individual energy needs, with the same macronutrient composition (45% carbohydrates, 20% protein, 35% fat). The energy and carbohydrate contribution for the 3 meals' diet was 20% at breakfast, 50% at lunch, 30% at dinner, whereas for the 6 meals' diet was 20% at breakfast, 10% at morning snack, 30% at lunch, 10% at afternoon snack, 20% at dinner, 10% at before bedtime snack. Each intervention lasted 12 weeks and there was no wash out period.

Isocaloric diet with 3 meals in order to maintain volunteers' weight, tailored to individual energy needs, with the same macronutrient composition. The volunteers were free to choose the foods they used to consume before. However, in order to assist them to adapt to the different meal frequency, individualized instructions were given to all volunteers before their entry to the study. An example of a 7-day diet menu was prescribed for both diet programs and analytical food exchange lists of different food groups were also provided.

Clinically useful change in serum glucose, defined as the restoration of glucose within normal limits during the 2-hour oral glucose tolerance test.

Clinically useful change in serum insulin, defined as the restoration of insulin within normal limits during the 2-hour oral glucose tolerance test. Improved insulin sensitivity.