Carb Loading Calculator

How carb loading works

Carb loading temporarily maximizes glycogen stores in the 24 to 48 hours before a long endurance event, giving you a bigger fuel tank to draw on during the race. It's most impactful for events lasting 90 minutes or longer, like a marathon, where glycogen depletion is a real limiting factor.

This means eating considerably more carbohydrate than your normal daily intake, often while reducing fiber slightly to avoid GI discomfort on race morning, and typically pulling back on fat and protein slightly to make room.

Where these numbers come from

The formulas and default values in this calculator are based on:

• General endurance sports nutrition guidance on carbohydrate loading targets (grams per kilogram of bodyweight) for events over 90 minutes

These are planning estimates for training purposes. Check with a coach, trainer, or physician before starting a new program or maxing out.