Protein and carbohydrate distribution among the meals: effect on metabolic parameters of patients with type 2 diabetes: a single-blinded randomised controlled trial

Studies have revealed that the timing of macronutrient ingestion may influence body weight and glucose tolerance. We aimed to examine the effect of high protein v. high carbohydrate intake at the evening meal on metabolic parameters of patients with type 2 diabetes. This is a single-blinded, parallel, randomised controlled trial. Ninety-six patients with type 2 diabetes, aged 32-65 years with a mean BMI of 28·5 (sd 3·4) kg/m2, were randomly assigned into one of these three groups: standard evening meal (ST), high-carbohydrate evening meal (HC) and high-protein evening meal (HP). Then, the patients were followed for 10 weeks. HbA1c, fasting blood glucose, fasting insulin, insulin resistance, TAG, LDL-cholesterol, VLDL-cholesterol, diastolic blood pressure, body weight, body fat percentage and waist circumference decreased significantly in all three groups (P < 0·05). HbA1c showed more improvement in the ST compared with the HP group (-0·45 (sd 0·36) v. -0·26 (sd 0·36)). Reductions in BMI and body weight were significantly higher in the ST compared with the HP group (P < 0·05). Reductions in total cholesterol, non-HDL-cholesterol and systolic blood pressure were significant in all groups, except for the HP group. Non-HDL-cholesterol:HDL-cholesterol remained unchanged in all groups. The results of the present study revealed that even distribution of carbohydrates and protein among meals compared with reducing carbohydrates and increasing protein at dinner may have a more beneficial effect on glycaemic control of patients with type 2 diabetes.