What food to eat when carb loading for endurance

December 24, 2025 •

3 min read

According to sports dietitians, an optimal carb-loading strategy can increase muscle glycogen stores by 20-50%, providing a critical energy boost for endurance events like marathons. Knowing what food to eat when carb loading is key to maximizing these stores without experiencing unwanted gastrointestinal distress on race day.

Quick Summary

Discover the ideal foods for carb loading, focusing on easy-to-digest carbohydrates to maximize glycogen stores before an endurance event. This guide explains the difference between simple and complex carbs, provides meal examples, and offers tips for proper timing to avoid digestive issues.

Key Points

Prioritize Easily Digested Carbs: Focus on low-fiber sources like white rice, white pasta, and bananas in the final 48 hours before an event to avoid stomach issues.
Strategic Timing is Crucial: Start increasing your carb intake 36-48 hours before the race, coinciding with a reduction in training intensity.
Reduce Fiber and Fat: Cut back on high-fiber whole grains, legumes, and fatty foods during the final days to prevent bloating and GI discomfort.
Mix Carbs and Protein Post-Workout: Combining a 4:1 ratio of carbs to protein within 30 minutes of a long workout enhances glycogen replenishment and aids muscle repair.
Replenish Liver Glycogen: The pre-race breakfast, consumed 2-3 hours before the start, helps top off liver glycogen stores depleted overnight.
Include Liquid Carbs: Use sports drinks or gels during carb loading if consuming enough solid food becomes difficult, or for quick energy boosts.
Hydrate Adequately: Water is stored alongside glycogen, so ensure proper hydration throughout the carb-loading process.
Practice During Training: Always test your race-day carb-loading strategy during training to determine what works best for your body.

What is Carb Loading and Why Does It Matter?

Carb loading is a nutritional strategy used by endurance athletes to maximize the storage of glycogen in the muscles and liver before a long-duration event. Glycogen is the body's primary fuel source during high-intensity exercise, and having a full reserve is crucial for delaying fatigue and maintaining performance.

The process typically involves reducing exercise intensity (tapering) while simultaneously increasing carbohydrate intake in the days leading up to a race. By reducing physical exertion and consuming a high-carbohydrate diet, the body becomes more efficient at storing glycogen. It's a fine balance, however; too much fiber or the wrong types of carbs can lead to digestive discomfort, bloating, and other issues that can negatively impact race day performance. For this reason, selecting the right foods is just as important as the quantity.

The Best Foods to Eat While Carb Loading

When choosing what to eat, the focus should be on high-carbohydrate foods that are also low in fat and fiber, especially in the 24-48 hours immediately preceding the event. While whole grains are excellent for daily nutrition, the fiber content can be problematic right before a race. Instead, opt for more refined or simpler carbohydrate sources to reduce the risk of stomach upset.

Easily Digestible Carbohydrates for Peak Performance

White Rice: A staple for many athletes, white rice is easy to digest and packed with carbohydrates. It provides a quick and efficient way to top off glycogen stores.
White Pasta: Similar to white rice, plain white pasta is a great, versatile option that is low in fiber. Avoid heavy, creamy sauces and opt for a simple marinara with lean protein.
Oats: Particularly instant or rolled oats, which are lower in fiber than steel-cut varieties, can be a great breakfast option. They provide sustained energy and are easy on the stomach.
Potatoes and Sweet Potatoes: Both offer a rich source of carbohydrates. Baking or mashing them makes them even easier to digest.
Bananas: As a low-fiber fruit, bananas are an excellent, portable snack option for a quick carbohydrate boost.
Plain Bagels or White Bread: These refined grain products are easy to digest and can form the base of a simple, carb-heavy meal.
Pancakes: A classic pre-race meal, especially when made with refined flour and topped with syrup, provides a simple carbohydrate source.
Dried Fruit: For quick fuel, dried fruits like raisins are a good source of simple carbohydrates, but should be consumed in moderation due to high fructose content.
Sports Drinks and Gels: If solid food is difficult to stomach, carbohydrate-rich beverages can be used to replenish glycogen.

Strategic Meal Planning and Timing

Your carb-loading plan should start 36 to 48 hours before the event. The night before, have a carb-rich, low-fat, and low-fiber dinner. This meal is important but should not be a massive binge. On race morning, consume a smaller, easily digestible breakfast 2 to 3 hours before the start. This final meal helps top off liver glycogen stores, which can be depleted overnight.

Comparison of Simple vs. Complex Carbohydrates for Carb Loading

Understanding the role of different carbohydrates is critical. While complex carbs are a dietary staple, their fiber content can be a double-edged sword during carb loading.


Feature	Simple Carbohydrates	Complex Carbohydrates
Digestion Speed	Rapid	Slow
Energy Release	Quick burst	Sustained
Fiber Content	Low (e.g., white pasta, bagels)	High (e.g., brown rice, whole wheat pasta)
Ideal for Carb Loading	24-48 hours before race to minimize digestion issues.	Early tapering phase (48+ hours before race) for steady energy and nutrients.
Examples	White bread, white rice, sports drinks, bananas.	Oatmeal, quinoa, starchy vegetables like potatoes.

Conclusion: Fueling Your Endurance with Precision

Mastering what food to eat when carb loading is a science that can significantly impact your performance and comfort on race day. The key is to strategically shift from a balanced diet of complex carbohydrates and fiber to one focused on easily digestible, carbohydrate-dense foods in the final days before your event. By prioritizing simple carbs, staying hydrated, and avoiding rich, high-fat, or high-fiber foods, you can ensure your glycogen stores are topped off and ready for the challenge ahead. Remember to practice your carb-loading strategy during training to see what works best for your body and to avoid any surprises on race day. Following a well-tested plan gives you the best possible chance to perform at your peak.

For further reading on athletic nutrition and fueling, a trusted resource is the American College of Sports Medicine.

Frequently Asked Questions

For an event like a marathon, you should begin your carb-loading protocol 36 to 48 hours before the race. This involves increasing your carbohydrate intake while tapering your exercise.

The night before a race, have a carb-heavy, low-fat, and low-fiber dinner. A good option might be white pasta with a simple tomato-based sauce and some lean chicken or fish.

Yes, you should include some protein and fat, but in smaller amounts than usual. The goal is to shift your macronutrient ratio to prioritize carbohydrates while keeping your overall calorie count similar to a normal training week.

Yes, in the 24-48 hours immediately before a race, simple and refined carbs like white bread and pasta are preferred over high-fiber whole grains. They are easier to digest and less likely to cause stomach upset.

A feeling of being slightly heavier or bloated is normal during carb loading, as your body stores water with glycogen. If it's causing significant discomfort, try eating smaller, more frequent meals instead of fewer large ones.

Yes, bananas are an excellent choice. They are a good source of easily digestible carbohydrates and are low in fiber, making them a safe and effective pre-race snack.

Yes, sports drinks are an effective way to supplement your carbohydrate intake, especially if you have a low appetite. They can help you meet high carb targets without feeling overly full from solid food.