How much carbohydrate can the body absorb during exercise?

The intestinal transporters for glucose (SGLT1) are saturated at ~60 g/hour. Using multiple carbohydrate sources (glucose + fructose, using GLUT5 transporters) allows up to 90 g/hour total absorption.

When is intra-workout carbohydrate supplementation needed?

For sessions under 60 minutes, intra-workout carbs provide minimal benefit for most athletes. For sessions 60-90+ minutes, 30-60 g/hour maintains glycogen and prevents performance decline.

What ratio of glucose to fructose is best for absorption?

A 2:1 glucose-to-fructose ratio (e.g., 60 g glucose + 30 g fructose = 90 g/hour) maximizes co-transport absorption. Popular products like Maurten and SiS use 2:1 maltodextrin-to-fructose blends.

Intra-Workout Carbohydrate Intake Calculator

Calculate optimal intra-workout carbohydrate intake rate (g/hour) based on exercise duration, intensity, and individual glycogen oxidation capacity.

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Frequently Asked Questions

How much carbohydrate can the body absorb during exercise?

When is intra-workout carbohydrate supplementation needed?

What ratio of glucose to fructose is best for absorption?