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Carbo Loading for Race Day: Is It the Right Strategy for You?

August 10, 2016 Posted in: Article , Eat Like a Pro

For decades, endurance athletes have ensured fast race times by loading up on carbohydrates prior to the big event. But what does carb loading really mean? Eating as much bread as you want the week prior to race day? Having a huge pasta dinner the night before? And how should amateur athletes and recreational exercisers use carbs? We'll clarify in this crash course on carbo loading.

Why Carbs?

During exercise, our bodies utilize our carbohydrate and fat stores for energy. Carbohydrates in the form of stored glycogen is the preferred fuel source over fat, as it provides a greater amount of energy per unit in a shorter amount of time. Carbs are also able to fuel both aerobic and anaerobic activity, whereas fat can only be used during aerobic, steady-state exercise. Your body works anaerobically during your most intense efforts, so it's key to ensure that you have enough stored carbohydrates for the hardest moments in your event.

There's just one problem: The carb stores in the body are relatively small, and they can change drastically from day to day based on exercise and carbohydrate consumption or restriction. This is why it's important to mind your carbohydrate intake before, during, and after your workouts when you engage in prolonged, high-intensity exercise.

Your Daily Carbohydrate Needs

To understand how carbo loading works, let's identify what your baseline carbohydrate needs are based on your level of activity, with an assist from experts at the Academy of Nutrition and Dietetics.


Level of Activity

Type of Exercise

Daily Carbohydrate Needs per Pound of Body Weight


Low-intensity, skill-based activities

1.5-2.5 grams


About one hour per day of moderate exercise

2.5-3.5 grams


One to three hours per day of moderate to high-intensity exercise

3-5 grams

Very High

Four to five hours per day of moderate to high-intensity exercise

4-6 grams


How to Carbo Load

You can help your body store additional carbohydrates in your muscles and liver by loading up on carbohydrates before a major race or event. In fact, an athlete can store anywhere between 1,800 and 2,000 calories of carbs in their bodies as glycogen by using this strategy. That amount of stored glycogen will provide fuel for 90 to 120 minutes of vigorous activity — that could mean the difference between an average race and a new personal record.

While each athlete's needs are unique, the Academy of Nutrition and Dietetics recommends carb loading by consuming 5 to 6 grams of carbohydrate per pound of body weight every 24 hours for the 36 to 48 hours prior to the event. Some experts recommend extending this preparation to 72 hours pre-event.

You don't need to worry about eating a lot of carbs all the time, however: Carbo loading is most effective for high-intensity, sustained exercise lasting longer than 90 minutes. Before these kinds of efforts, focus on nutrient-rich carbohydrates such as whole grains, fruits, vegetables, and low-fat dairy. You should also taper your training as prescribed by your coach or trainer so that these carbs can top off your glycogen stores instead of fueling other hard efforts before the big race.

On the night before the main event, avoid going overboard with carbs or trying new foods. Enjoy a balanced, nutrient-dense meal that your body is familiar with, and eat an amount that would be normal for you on any given night. This will help to prevent any unwelcome cramping or stomach issues during the event. Use the same strategy for breakfast on the morning of race day: Eat a meal you'd typically have prior to any other bout of exercise. If you've followed the basic principles of carbo loading for the last day or two, your body will already be prepared to give its best performance.

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