AIM: The present study investigated the effects of high and low glycemic index (GI) 24 h recovery meals on the physiological responses and subsequent athletic performance, following a glycogen depleting protocol. METHODS: Ten well trained cyclists (age, 33.6+/-7.4y, height, 175.3+/-7.6 cm, weight 74.5+/-8.2 kg, and VO(2max), 60.5+/-6.0 mlkg(-1)min(-1)) participated in two trials in a randomized cross- over design. On day 1, subjects performed a glycogen depleting protocol after which they then consumed either high or low GI recovery diets over the next 24 h, which provided 8 g.kgBW(-1) of carbohydrate. On day 2, the subjects returned to the laboratory, 2- 3 h postprandial, to perform a 40 km time trial (TT) on the Velotron cyclePro(c) ergometer. RESULTS: No difference was observed in TT performance times between the high GI (93. 5+/-9.29 min) trial and the low GI (90.7+/-11.1 min) trial (t=1.1; P=0.35). Additionally, no differences in carbohydrate (F=1.1, P=0.37) fat (F=1.1, P=0.40) oxidation or blood glucose concentration (F=0.9, P=0.5) was observed. DISCUSSION: The results of the present study suggest that the ingestion of a high GI carbohydrate 24 h recovery diet following glycogen depleting exercise, has no greater effect on endurance performance than consuming a low GI carbohydrate 24 h recovery diet. It may be concluded from these results that, provided enough carbohydrate is consumed during a 24 h recovery period, there is no difference in subsequent endurance performance.
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