Effect of protein-carbohydrate supplementation after glycogen depletion on plasma insulin, glucose response and endurance performance in active university students

This study aimed to investigate the effect of protein-carbohydrate supplementation after glycogen depletion on plasma insulin, glucose response and endurance performance in active university students. Thirty male undergraduate men physical education students (age=22.53±1.50 yr, weight=70.13±9.56 kg, height=174.05±5.41 cm) were active in one sport and passed four credit practical course divided into four groups randomly: proteincarbohydrate, carbohydrate, protein supplement and placebo. Constant power ergometer was used for determination of maximum power output (Wmax) and time to exhaustion. After three days, subjects that were overnight fast, performed glycogen depletion protocol at 8:30 A.M. After glycogen depletion, blood sample collected immediately in order to analyze plasma insulin and glucose. The 4 groups consumed Protein-carbohydrate (80g CHO, 28g PRO, 6g FAT), carbohydrate (108g CHO, 6g FAT), protein (40.7g PRO) supplement and placebo (water) 10 minutes and 2 hour post exercise respectively. Thirty minutes after second dose supplement consumption, blood sample collected again in order to analyze plasma insulin and glucose. After recovery subjects performed time to exhaustion test 4 hours after glycogen depletion protocol and recovery. T test used to determined intergroup differences. ANOVA and TUKEY test were used to compare data between the groups and in every case (p<0.05).The results showed insulin, glucose response and time to exhaustion to protein-carbohydrate supplement was greater than carbohydrate, protein and placebo respectively. Carbohydrate supplement also was greater than carbohydrate, protein and placebo in all of variables. In conclusion, the results suggest that muscle glycogen synthesis accelerated and increased with proteincarbohydrate supplement post exercise and glycogen depletion than carbohydrate and protein supplement and time to exhaustion increased in the next exercise or match via this supplementation protocols.