Research

Hormonal

Ingesting carbohydrate during prolonged exercise (≥120 min) improves subsequent time-trial performance, whereas ingesting carbohydrate only before exercise does not.

If you are exercising for more than two hours, do not rely on eating 30 minutes before you start. Instead, consume carbohydrates (approx. 2g per kg of body weight) continuously during the exercise. Eating only before the workout may actually hinder your performance due to blood sugar fluctuations, whereas eating during the workout improves your ability to finish strong.

GoodQualifiesHIGH confidence
We conclude that 1) preexercise ingestion of CHO improves performance only when CHO ingestion is maintained throughout exercise, and 2) ingestion of CHO during 120 min of cycling improves subsequent TT performance.
Mark A. Febbraio et al. · Journal of Applied Physiology · 2000

Why this rating

Randomized, double-blind, crossover design with trained subjects, though sample size is small (n=7).

Source

Effects of carbohydrate ingestion before and during exercise on glucose kinetics and performance

Mark A. Febbraio et al. · Journal of Applied Physiology · 2000

DOI 10.1152/jappl.2000.89.6.2220

crossover · n=7Cited 189×
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DOI resolved against Crossref · corpus check 2026-06-10

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