HIGH-CARBOHYDRATE DIET IMPROVES FITNESS AND MUSCLE SIZE
Toma, K., Werner, T., Hikida, R. S., Gilders, R. M., Staron, R. S., Roe, R. M., & Hagerman, F. C. (2007). High-carbohydrate versus high-protein, low-carbohydrate diets on high-intensity aerobic training. ACSM Annual Meeting New Orleans, Presentation Number, 2254.
The purpose of this study was to compare the effects of a high-protein, low-carbohydrate diet versus a traditional high-carbohydrate diet on high-intensity aerobic training. Male college students (N = 17) were measured for body weight, %body fat, and maximal oxygen consumption (VO2), and fasting blood and muscle biopsies were taken before and after a diet-training intervention. Ss having similar VO2 were paired and assigned to either group while participating in progressive aerobic training on a rowing ergometer for seven weeks.
Ss maintained their assigned % food distribution, but consumed less food than the estimated caloric expenditure. During training, Ss maintained similar post-exercise heart rates while workload increased in both groups. The high-carbohydrate group performed at a higher intensity than the low-carbohydrate group. Percent body fat decreased, VO2 increased, and total cholesterol decreased in both groups. Skeletal muscle fiber size (diameter) increased in the high-carbohydrate group and decreased in the low-carbohydrate group.
Implication. In both diet groups, high-intensity aerobic training improved cardiovascular fitness, but the high-carbohydrate group also increased skeletal muscle size, which could improve exercise performance.
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