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How to Carb Load for Race Day


At Siras Performance, we’re committed to improving the understanding of the physical and mental benefits of sports nutrition and exercising.

Carb loading is a common term utilised amongst groups of endurance athletes. This term refers to the technique that increases your body’s carbohydrate stores prior to a race to assist your body in optimal performance on race day.

McDowell (2021) explains the science behind this concept. When you consume carbohydrates, your body stores them as glycogen in your muscles and liver. Glycogen is the most accessible form of energy however it is not the only source.

Throughout a race, you burn both glycogen and fat, however fat is not efficient in burning and thus your body would need to work harder to convert it to fuel. If you run out of glycogen in a race, you will feel a slump in performance as your body is converting fat into energy (Get Fit San Francisco, 2019).

Who should carb-load?

If you are looking at exercising for more than 90 minutes, your body will require carbohydrate stores. If your mileage is under 10km, you generally would not require carb-loading prior to your race.

What foods are good for carb loading?

The top reported carb-loading foods may be: oatmeal, bread, pancakes, waffles, bagels, tortillas, rice, yoghurt and fruit juice. (McDowell, 2021). Many fruits are high in fiber and that may cause stomach pains throughout your race, so if you do consider these then you should peel the skins off your fruit or rely on the trusty banana which is a low-fiber choice

How many carbs should you eat?

One meal won’t sufficiently fuel glycogen into your muscles. It is recommended to start carb-loading two to three days prior to race day. Generally these days require rest or low mileage active rest, thus the body will accumulate these. Over these three days 85 – 95 percent of your calories should come from carbohydrates (McDowell, 2021)

 High5 (2021) recommends that runners reduce mileage four to five days before your event. Two days prior, your carbohydrate intake should increase to 10 grams per kilogram of bodyweight. There are ways in which you can get in your carbohydrates without eating too often or large meals, these are energy drinks or energy bars.

Topping up your carb stores during a race

Your body is burning glycogen at a rapid speed, thus you should replenish the lost carbohydrates by consuming an energy drink, gel or chew every 30 to 45 minutes. These supplements also contain electrolytes which will ensure your fluid is balanced. Some include caffeine which may assist you in getting through those final miles.

Remember that it is your journey. Listening to your body is essential in performing physically. Ensure that you are providing your body with the support that it needs, now that you’ve read this blog, you’re halfway there ;) Now it’s time to take action!

’til next time,

Siras Performance

Please note: Always consult a health professional prior to changing your exercise and nutrition regimes to ensure its suitability for your individual situation. 


Bede, P.N. 2014. How to Carb-Load for Marathon Week.

Get Fit San Francisco. 2019. Fueling Up: Why You Should Carbo-Load Before a Race.

High5. 2021. How to carb load.

McDowell, D. 2021. How Proper Carb-Loading Can Help You Crush Your Next Race.

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