Carb Loading Calculator

What is carb loading?

Carb loading means eating more carbohydrate than usual in the day or two before a long race, so your muscles start with their glycogen stores as full as possible. It's aimed at events lasting over about 90 minutes - an Ironman, a 70.3, a marathon - and isn't worth the bother for a sprint or a short run.

The usual guideline is 10-12 g of carbohydrate per kg of body weight per day, for the 36-48 hours before the race (Burke et al. 2011, restated in the 2016 Thomas, Erdman & Burke joint position statement). That's a lot of food - for a 70 kg athlete, around 700-840 g of carbs a day - which is why the split across the day matters as much as the total.