Which of the following describes carbohydrate loading?: A comprehensive guide to the endurance athlete's fuel strategy

October 25, 2025 •

2 min read

According to Sports Dietitians Australia, carbohydrate loading can improve performance in endurance events lasting over two hours by 2–3%. This strategy, which answers the question, which of the following describes carbohydrate loading?, involves a specific dietary and training regimen to maximize the body's glycogen stores ahead of a competition.

Quick Summary

A nutritional technique for endurance athletes, carbohydrate loading maximizes glycogen stores in muscles and the liver before prolonged events by increasing carbohydrate intake and tapering exercise.

Key Points

Endurance-Specific Strategy: Carbohydrate loading is a nutritional tactic primarily used by athletes competing in endurance events lasting 90 minutes or longer.
Maximize Glycogen Stores: The main objective is to maximize the storage of glycogen, the body's primary energy source during intense exercise, in the muscles and liver.
Modern Method is 1-3 Days: The most common approach involves increasing carbohydrate intake (10-12 g/kg body weight) for 1–3 days before an event, often without a prior depletion phase.
Pair with Tapering: To be effective, the increased carb intake must be combined with a reduction in exercise volume and intensity, known as tapering.
Choose Low-Fiber Carbs: Focus on easily digestible carbohydrates like white pasta, rice, and potatoes to avoid gastrointestinal issues during competition.
Expect Temporary Weight Gain: Temporary weight gain of 1–2 kg is normal and results from the water retained with stored glycogen.
Practice During Training: Athletes should practice their carb-loading strategy during training runs to identify what works best for their body before race day.

Understanding the Basics of Carbohydrate Loading

For endurance athletes, carbohydrates are the primary source of fuel during prolonged, high-intensity activity. The body stores these carbohydrates as glycogen in the muscles and liver. These reserves are limited and typically sustain moderate to high-intensity exercise for about 90 minutes. Depleting these stores necessitates a switch to fat for energy, a less efficient process leading to fatigue.

Carbohydrate loading is a deliberate strategy to super-saturate these glycogen tanks, providing a larger fuel supply. It benefits endurance events lasting 90 minutes or longer. Increasing carbohydrate intake while reducing training volume allows the body to store more glycogen, delaying fatigue and enhancing endurance.

The Evolution of Carb Loading: Classic vs. Modern Methods

Carb loading has evolved since the 1960s. The original "classic" method included a depletion phase before loading, but a more practical, modern approach is now common.

Classic Method

Depletion Phase: 3–4 days of intense exercise and a low-carbohydrate diet to exhaust glycogen.
Loading Phase: Final 3–4 days with significantly increased carbohydrates (70%+ calories) and tapering.

Modern Method

Duration: Shorter 1–3 day phase before the event.
Depletion: Often omitted; trained athletes can achieve similar glycogen levels without it.
Intake: Consuming 10–12 grams of carbohydrates per kilogram of body weight daily while tapering.

Comparison of Carb Loading Methods


Feature	Classic Method	Modern Method
Duration	6–7 days	1–3 days
Depletion Phase	Required	Optional/Often omitted
Carb Intake	Increased only in the last 3–4 days	Increased throughout the 1–3 day phase
Training	High intensity early, tapering later	Tapering throughout
Convenience	Less convenient	More practical
Effectiveness	Highly effective, but riskier	Equally effective for trained athletes

A Step-by-Step Guide to Modern Carb Loading

Modern carbohydrate loading involves increasing daily carb intake to 10-12 grams per kilogram of body weight for 1-3 days before an event, while significantly reducing training. It's recommended to choose easily digestible, low-fiber carbs like white rice and pasta, and stay well-hydrated, as water is stored with glycogen. Liquid carbs can help meet targets, and it's best to spread intake across smaller meals.

Common Mistakes to Avoid

Avoid high-fat or high-fiber foods, and ensure adequate rest. Carb loading is a multi-day process, not a single large meal, and should always be tested during training before race day. Temporary weight gain from glycogen and water is expected.

Conclusion

Carbohydrate loading is a proven strategy for endurance athletes to maximize glycogen stores before prolonged events. It's a calculated adjustment of diet and training, not a casual binge. The modern 2–3 day protocol, emphasizing easily digestible carbohydrates, can boost fuel reserves, delay fatigue, and optimize performance. It is a critical element for endurance athletes aiming to go the distance on race day. {Link: NSCA https://www.nsca.com/education/articles/kinetic-select/carbohydrate-loading/}.

Frequently Asked Questions

Carbohydrate loading is a dietary strategy used by endurance athletes to increase the glycogen stores in their muscles and liver in the 1–3 days leading up to a prolonged event. It involves increasing carbohydrate consumption while simultaneously reducing training volume.

Carbohydrate loading is most suitable for endurance athletes participating in prolonged, high-intensity events that last 90 minutes or longer, such as marathons, triathlons, and long-distance cycling.

No, the classic method involving a glycogen depletion phase is no longer considered necessary. Research shows that well-trained athletes can achieve maximal glycogen stores with a simpler, 2–3 day loading phase that incorporates tapering.

During carb loading, focus on easily digestible, low-fiber, carbohydrate-rich foods like white rice, pasta, white bread, and potatoes. Sports drinks and fruit juices can also help meet high carb targets without excessive bulk.

Common side effects include temporary weight gain (due to water retention), bloating, and digestive discomfort, especially if high-fiber foods are consumed excessively.

Yes, it is possible. Your body has a saturation point for glycogen storage. Consuming excessively high amounts of carbohydrates beyond recommendations may not offer further performance benefits and can lead to gastrointestinal discomfort or sluggishness.

Spread your carbohydrate intake across smaller, more frequent meals and snacks throughout the day. This is generally more effective and easier on the digestive system than trying to consume a large number of carbs in one or two big meals.

No, carb loading is generally not necessary for races lasting less than 90 minutes. Your body's normal glycogen stores are sufficient for shorter distances, and a carb load offers no significant performance advantage.

Experts typically recommend consuming 10–12 grams of carbohydrates per kilogram of body weight per day during the 1–3 day carb-loading phase.

Hydration is crucial because glycogen binds with water in the body. Adequate fluid intake is needed to facilitate proper glycogen storage and to ensure you are well-hydrated for the event.