The effects of the glycaemic index of carbohydrate meals on metabolism, recovery and endurance performance

Moore, Laura Jayne Suzanne

Abstract

The aim of this thesis was to investigate the effect that consuming pre- and post exercise meals, varying in GI, would have on physiological responses and subsequent endurance performance.

Study 1 investigated the effects of consuming either a low or high GI meal 45 min prior to exercise on cycling TT performance. It was observed that consuming a low GI meal 45 minutes prior to performing a 40k TT, resulted in a significantly improved performance (p = 0.009) compared to the ingestion of an isocaloric high GI pre- exercise meal (93 ± 8 min vs. 96 ±7 min for low and high GI, respectively). The results suggested that the ingestion of the low GI food led to an increase in the availability of CHO and greater CHO oxidation throughout the exercise period and subsequently spared limited muscle and liver glycogen stores.

Study 2 investigated the effects of low and high GI 24 h diets, following glycogen depleting exercise, on TT performance the following day. No difference was observed in TT performance following low (90.7 ±11.1 min) and high (93.5 ± 9.29 min) GI, 24 h recovery diets (p = 0.35). This study concluded that provided the amount of CHO consumed during the recovery period is sufficient enough to replenish depleted muscle glycogen stores, the GI of the recovery diet offers no further benefit to performance.

Study 3 investigated the effects of high and low GI recovery meals on TT performance following a short term recovery period from a glycogen depleting exercise. No significant difference was observed in TT performance between the low (90.7 ± 11.1 min) and high GI (93.5 ± 9.3 min) trials (t = 1.1; p = 0.35). This study concluded that if the following exercise bout is of short duration, and not long enough to challenge glycogen stores, provided the amount of CHO is sufficient during the recovery period, the GI of short- term recovery diets has no influence on subsequent exercise performance.

In conclusion, the findings presented in this thesis should contribute to and support previous research within this area and help to contribute to the body of knowledge through greater ecological validity.

Citation

Moore, L. J. S. (2009). The effects of the glycaemic index of carbohydrate meals on metabolism, recovery and endurance performance. (Thesis). University of Hull. Retrieved from https://hull-repository.worktribe.com/output/4213085

• Thesis Type: Thesis
• Deposit Date: Sep 25, 2012
• Publicly Available Date: Feb 22, 2023
• Keywords: Sport science
• Public URL: https://hull-repository.worktribe.com/output/4213085
• Additional Information: Department of Sports Science, The University of Hull
• Award Date: Sep 1, 2009