Background & aims: We aimed to compare the effects of protein to carbohydrate ratio and physical form in dairy on glucose homeostasis and food intake.
Methods: In a crossover design, 20 healthy males consumed 250 g of one of five treatments, plain yogurt, plain yogurt with honey, strawberry yogurt, skim milk or orange juice, as mid-morning snacks. Food intake was assessed 120 min later. Blood glucose, serum insulin and subjective satiety were measured pre- and post-meal.
Results: Pre-meal glucose responses were attenuated in a dose-dependent manner to the increasing protein and decreasing sugars in dairy. Protein to carbohydrate ratio correlated negatively with pre-meal glucose due to improved efficacy of insulin action rather than to increased insulin concentrations. Compared with a carbohydrate beverage (orange juice), cumulative blood glucose was lower after dairy snacks but the effect was not explained by their protein to carbohydrate ratio or physical form. Skim milk, with the lowest protein to carbohydrate ratio among dairy products, attenuated both pre-meal and post-meal glucose compared to orange juice without inducing higher insulin levels. There was no effect of treatments on appetite and food intake.
Conclusions: While pre-meal glycemia was attenuated dose-dependently to increased protein to carbohydrate ratio in dairy snacks, the contribution of dairy products to post-meal glucose control and to satiety and food intake was independent of their protein to carbohydrate ratio and physical form in healthy men. This trial was registered at clinicaltrials.gov as NCT01673321.
Keywords: ANOVA; Appetite; BMI; Energy intake; Glycemia; Milk; PCR; Protein; VAS; Yogurt; analysis of variance; body mass index; iAUC; incremental area under the curve; protein to carbohydrate ratio; visual analog scale.
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