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Carbs for Training Calculator

How much carbohydrate to eat for the training you do, and around endurance events.

Your details

Units

From your profile. Changes here update it everywhere.

Training load

For during-race fuelling, e.g. 240 for a 4-hour marathon.

For general information only; not medical advice. Consult a qualified professional before making health decisions.

How this is calculated

Daily, per kg of body weight

Light 3–5 g · Moderate 5–7 g
High 6–10 g · Very high 8–12 g

Events

Before: 1–4 g/kg, 1–4 hours ahead
During: 30–60 g/h for 1–2.5 h; up to 90 g/h beyond that

These are ranges for athletes in training. Needs vary with intensity, body size and goals; a sports dietitian can tailor them.

Sources

  • Thomas DT, Erdman KA, Burke LM (2016), Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: nutrition and athletic performance. Med Sci Sports Exerc 48:543–568.

About the carbs for training calculator

Carbs fuel hard training

Carbohydrate is stored in your muscles and liver as glycogen, the main fuel for hard or long exercise. When stores run low, pace drops and effort climbs. Eating enough for your training load keeps sessions high quality and helps recovery between them.

Read more about the Carbs for Training calculator

Around races

A carb-rich meal 1–4 hours before tops up stores. In events longer than about an hour, taking in carbohydrate during the race delays fatigue. Above 2.5 hours, mixing glucose and fructose lets you absorb up to about 90 g an hour, but practise it in training first: guts need training too.

Frequently asked questions

How many carbs do runners need?

Around 5–7 g per kg of body weight on days with about an hour of training, and 6–10 g/kg in heavy training weeks.

How many carbs per hour in a marathon?

Most runners do well on 30–60 g an hour. Trained guts can handle up to about 90 g using glucose-fructose products.

Do I need to carb-load?

For events over about 90 minutes, eating 10–12 g/kg for 1–2 days before can help. For shorter races, normal eating is enough.