Carbohydrate Intake for Athletes in Training
by Melinda Burris

Carbohydrates are a key component of our daily diet as the human body relies on these types of food sources for fuel. Stored as glycogen in the muscles and liver, carbs are your body’s go-to source for energy needed for everything from training to competition to completing your daily tasks.

Your glycogen stores are constantly in flux based on what you are doing and how hard you train. High-intensity exercise requires the highest intake of carbohydrates for the glycogen stores necessary to perform, with most individuals depleting their bodily stores after an hour and a half to two hours of strenuous exercise.¹ Elite athletes commonly have to replenish their carb intake either during exercise, generally referred to as exogenous or outside fuel sources, intended to help the body restore its glycogen stores more quickly, allowing for sustained activity.

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Common sources for this carb refueling include natural food sources that are rich in carbohydrates and energy bars or drinks. With the latter, you have to be mindful of reading ingredient labels carefully, as many energy/sports drinks and bars are loaded with additives such as sugar and caffeine, which add extra “empty” calories and can be dehydrating.

It is important to understand that when you are demanding your body keep up an elevated level of exercise, you cannot depend on burning body fat for immediate results, as this process is slower than simply replenishing your carbohydrate intake. The body saves up fat as a survival mechanism, so it goes to those resources as a last resort.

Because it is a must for high-endurance athletes who require the performance enhancement that outside carbohydrate intake provides, the question of precisely what sources and amounts these athletes should target for consumption has been an open debate for more than half a century.¹ It is crucial that serious athletes not allow themselves to get caught up in the hype that so often surrounds the lucrative, but also often deceptive, sports nutrition market and avoid buying into marketing schemes that promote the next trendy product that promises but fails to deliver results.¹ Educating yourself on what scientific studies have proven to be most effective and healthy for the body will serve your short-term and long-term care needs.

Carbohydrate Intake Required Per Hour

If you are questioning how much carbohydrate you need to consume each hour, you need to analyze your current physical condition honestly.

Are you maintaining robust glycogen stores? To do so, you need to consume “a light but carb-dense meal or snack 2-3 hours”¹ before any training session or competition. If you fail to prepare by fueling your body beforehand, you will find your glycogen stores—and your energy level—are more rapidly depleted. You place yourself in the position of having to refuel more often during exercise to sustain the demands you put on your body.

These recommendations also assume that you are actively looking to optimize your performance level—participating in high-intensity physical exertion versus the minimum requirements the body has for daily living. The amount of carbohydrates you will need will vary based on the activity you are involved in. For example, a long-distance runner taking part in a two-hour run, going at a steady pace, will need less refueling than those who are running sprints or doing hurdles at a fast pace over a short duration (less than 30 minutes).¹

Research shows that when athletes eat an appropriate amount of carbohydrates before participating in high endurance periods lasting for less than one hour, they do not need to engage in refueling during activity. The body’s glycogen stores should be sufficient to enable optimal performance without resorting to refueling.

That said, it is very important that athletes plan and eat a recovery meal that is rich in carbohydrates to aid the body in the recovery process. Doing so speeds up recovery times and enables athletes to compete again more quickly. Long-duration exercise times (45-60 minutes) of sustained, high-intensity activity have been shown to benefit from the consumption of small amounts of carbohydrate or a carbohydrate mouth rinse,¹ which is when you swish with a carbohydrate-rich liquid for 5-10 seconds at regular intervals. This puts less pressure on the body by not fully engaging the digestive system during strenuous exercise. Researchers believe that by engaging the taste buds, the brain is prompted to react to the stimuli of carbohydrates.

Nutrient Timing

Natural sources of carbohydrates include milk, yogurt, and fruit juice. These food sources can be consumed on their own or combined with fruits to make a carbohydrate-rich smoothie. The concept of nutrient timing, developed by exercise physiologist John Ivy, calls for athletes to train while consuming endurance carbohydrates in order to train the gut to tolerate these foods. Reloading refers to your recovery meal or snack of carb-heavy foods, so your muscles have sufficient glycogen stores to draw from the following day.²

Timing comes into play because it is natural for your muscles to crave carbohydrate replenishment within half an hour of completing strenuous exercise. Athletes often find it difficult to digest large meals or even solid foods at this time²; however, this is one reason smoothies and nutrition drinks have become so popular.

As you would expect, the heavier you train, the more carbohydrate intake you will require to maintain a consistent level of performance.  Conversely, when you train less, your body demands less.² Experts stress that it is essential to calculate your appropriate carbohydrate consumption not in terms of total calories but in grams consumed based on individual needs dictated by your specific training workload.³  A balanced diet that provides the necessary amount of carbohydrate, protein, and fat sources is instrumental to athletic endurance.

Since training levels should fluctuate based on the season and competition times, your dietary intake needs will vary as well. Again, planning and timing to ensure you give your body the resources it needs for exercise and proper recovery when it needs it are essential to achieving peak performance levels.

References:

1. Blow, A. (2025). How Much Carbohydrate Do Athletes Need Per Hour?
2. Memorial Hermann. (2025). The Best Carbs for Athletes.
3. Fitzgerald, M. (2025). Rethinking the 60% Carbohydrates Rule.

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