The nutritional and metabolic effects of a carbohydrate-rich diet in a glycogen supercompensation training regimen

It has been suggested that glycogen depletion followed by a protein-fat diet and a carbohydrate-rich diet improves performance. This study was designed to determine the nutritional and metabolic effects of a carbohydrate-rich diet in a glycogen supercompensation training regimen. Four male subjects participated in a 5-week protocol of which the first 3 weeks were devoted to a control period and the last 2 weeks to the experimental phase of the study. The variables measured before, during, and following the experimental phase included anthropometric and basal metabolic rate measurements, urinary and serum analysis for vitamins, SMA 12/60 blood profile and aerobic performance (VO2max). Results indicated an appreciable modification of the metabolic and nutritional profile of the subjects as a result of the diets. During the protein-fat diet there was a decrease in serum glucose and resting respiratory quotient and an increase in cholesterol, blood urea nitrogen, riboflavin, and N1-methylnicotinamide excretion. Subsequent to the carbohydrate-rich diet there was an increase in triglycerides and vitamin C, riboflavin, and thiamin excretion while there was a decrease in serum blood urea nitrogen, and N1-methylnicotinamide excretion. Aerobic performance was slightly decreased and the mean postexercise lactate levels were slightly higher after the carbohydrate-rich diet. It was hypothesized that the reduced niacin intake during the carohydrate-rich diet may hamper the aerobic oxidative pathways.