No Effect of Delaying a Carbohydrate-Rich Breakfast on Afternoon High-Intensity Intermittent Exercise Performance in Trained Games Players: A Randomized, Single-Blind, Placebo-Controlled Trial

Category Primary study
JournalINTERNATIONAL JOURNAL OF SPORT NUTRITION AND EXERCISE METABOLISM
Year 2025
Links Pubmed, DOI
This study tested the hypothesis that delaying consumption of a carbohydrate-rich breakfast by 2 hr would impair prolonged highintensity intermittent exercise performance in the afternoon. Fifteen intermittent games players (mean +/- SD: age: 24 +/- 6 years; (center dot)VO2peak: 46 +/- 6 mlkg-1min-1) completed a randomized, single-blind, placebo-controlled crossover study with two trials (EARLY and DELAY) matched for dietary intake. In EARLY, participants consumed a high-carbohydrate (semisolid) breakfast shake (2 g/kg BM maltodextrin, 1 ml/kg BM orange squash, 0.15 g/kg BM xanthan gum, 0.067 g/kg BM artificial sweetener, and 6 ml/kg BM water) at 8 a.m., followed by a taste and texture matched, but energy depleted, placebo shake 2 hr later. In DELAY, the order of these shakes was reversed. Three hours following a high-carbohydrate lunch (888 +/- 107 Kcal, 145 +/- 28 g carbohydrate), participants completed a 90-min intermittent cycling test, consisting of two 40-min halves, with 10 min of rest in between. Each half involved 18 repeated 2-min blocks of steady-state cycling (100 s; 35% Wmax), followed by 15 s of unloaded pedaling and a 6-s allout sprint. There were no differences in peak power (first half: mean difference [95% confidence interval]: 6.6 [-10.9, 24.1] W, d= 0.03 and second half: 8.5 [-6.5, 23.6] W, d= 0.04) or mean power (first half: mean difference: 6.4 [-10.7, 23.5] W, d = 0.03 and second half: mean difference: 7.3 [-6.5, 21.3] W, d = 0.04) during the sprints between the DELAY and EARLY conditions. In contrast with our hypothesis, these data provide no evidence that delaying consumption of a carbohydrate-rich breakfast by 2 hr impairs prolonged high-intensity intermittent exercise performance in the afternoon.
Epistemonikos ID: cf6c6d8b40e5b95bb76180eb5baf8a68f1a187c4
First added on: Mar 21, 2025