Effect of Meal Composition and Exercise Training on Glucose and Insulin Excursions Over 12 h

Abstract

Increasing meal frequency may help weight loss and regulation of blood glucose levels. However, the impact of meal composition and exercise training on glucose or insulin levels throughout the day is unclear. PURPOSE: Thus the purpose of this study was twofold: 1. To compare the differences in the glucose and insulin excursions in response to frequent high carbohydrate meals vs. high protein meals, and 2. To establish the effect of short-term exercise training on the glucose and insulin response to frequent high carbohydrate meals. METHODS: Ten obese men and women were studied on two occasions, where they consumed 6 meals every 2 h (250 kcal/meal). On one occasion they consumed a high carbohydrate meal (HC)-14% protein, 21% fat, and 65% carbohydrate-1500 kcal), and on the second occasion they consumed a high protein meal (HP)- 45% protein, 35% carbohydrate, 20% fat-1500 kcal) in a randomized order. In addition, all subjects completed 15 days of exercise training (1 h/day, 70% VO2 max) and then repeated the HC study day. Blood glucose and insulin levels were measured every 10 min for 12 h. RESULTS: The HC meal resulted in a higher glucose level (total area under the curve-AUC) over the 12 hr than the HP meal (395±18 vs. 364±10 mmol/L*min, respectively, P<0.05). Likewise insulin AUC was greater during the HC condition (192,966±19,918 pmol/L*min) than the HP condition (162,519±22,772 pmol/L*min, P<0.05). Dividing the meals into 2 h increments did not reveal any pattern of response in glucose or insulin concentrations across the day. Exercise training did not significantly alter the total AUC over 12 h for either the glucose or insulin concentrations. CONCLUSIONS: In obese individuals, a higher protein meal given frequently results in lower glucose and insulin concentrations over the course of 12 h as compared to a higher carbohydrate meal. Short term exercise training had no effect on the glucose or insulin excursions over the course of a day. Supported by NIH R21DK084467-01