The gut's tolerance for race-day carbohydrate loads is trainable through a structured protocol, not a fixed trait
Interpretation
Costa et al.'s two-week repetitive gut-challenge RCT reduced GI symptoms by 60-63% versus placebo and improved distance-trial performance by 4.3-5.2% — direct evidence that gastric comfort and absorption capacity under high carbohydrate loads can be deliberately trained in a short, structured window before a race.
Practical implication
Recommend a 2-week structured gut-training block (progressively increasing race-pace carbohydrate intake during training) ahead of any athlete adopting a new, higher fueling target — not an assumption that tolerance will simply appear on race day.
Sources
1 source, independently verified.
APNM 42(5):547-557. Two weeks of repeated carbohydrate-challenge during exercise reduced GI symptoms by 60% (gel-disc) and 63% (food) versus placebo, and improved distance-trial performance by 4.3-5.2% — direct evidence the gut's tolerance for race-day fuelling loads is trainable, not fixed.