Mastering Your Fuel: What foods to eat when carb loading?

October 7, 2025 •

5 min read

Endurance athletes who properly carb-load can increase their muscle glycogen stores by up to 50%, delaying fatigue and enhancing performance during long events. Knowing what foods to eat when carb loading is a critical strategy for maximizing these energy reserves and avoiding pre-race digestive issues.

Quick Summary

This article details the best foods for effective carb loading, emphasizing low-fiber, high-carbohydrate options for maximum glycogen storage without stomach upset. It covers foods to prioritize, which to limit, and practical tips for timing and hydration to optimize your endurance event performance.

Key Points

Prioritize Low-Fiber Carbs: Focus on white versions of rice, pasta, and bread to avoid digestive upset, especially in the 24-48 hours before an event.
Reduce Fat and Fiber Intake: Limit high-fat foods and bulky fiber sources to make consuming the required high volume of carbohydrates easier.
Include Simple Sugars: Use bananas, fruit juices, and honey for quick, easily digestible energy boosts to help reach your daily carb targets.
Stay Hydrated: Drink plenty of fluids, including sports drinks, to support glycogen storage and maintain electrolyte balance.
Practice During Training: Never try a new carb-loading strategy on race day; test it during a long training run to see how your body reacts.
Use Liquid Carbs: If you find it hard to eat enough solid food, carbohydrate-rich liquids like juices or sports drinks are an effective alternative.
Eat Frequently: Consume smaller, more frequent meals and snacks rather than a few large, heavy ones to make reaching your carb goals more palatable.

Carbohydrate loading, or 'carb-loading,' is a strategic dietary approach used by endurance athletes to maximize the storage of glycogen in their muscles and liver. Glycogen is the body's primary fuel source during prolonged, high-intensity exercise. By topping off these stores, athletes can delay fatigue and maintain performance during events lasting longer than 90 minutes. However, the success of this strategy hinges on selecting the right foods at the right time. The goal is to consume a high volume of carbohydrates without causing gastrointestinal (GI) distress, which often means temporarily shifting away from your usual high-fiber, whole-grain diet.

The Science Behind Carb Loading

During a period of reduced training volume (tapering), athletes strategically increase their carbohydrate intake to fill their muscle and liver glycogen stores. The body holds about 2,000 calories of glycogen in total, but carb-loading can push this capacity even higher. For most athletes, a loading phase of 2–3 days is sufficient. The typical recommendation is to increase carbohydrate intake to 8–12 grams per kilogram of body weight per day. This means a 70 kg athlete would aim for 560–840 grams of carbs daily. Crucially, this requires consuming extra carbs while simultaneously reducing fat and protein intake to prevent excessive calorie consumption and unwanted weight gain.

What to Prioritize: Best Foods for Carb Loading

For most of the carb-loading phase, particularly the 24-48 hours directly before an event, easily digestible, low-fiber carbohydrates are the priority. This helps to reduce the risk of GI issues, such as bloating and gas, during the race.

Easily Digestible Carbohydrates

These are the workhorses of any carb-loading plan. They provide a high concentration of carbs with minimal fiber, making them easy to consume in large quantities.

White Rice and Rice Products: White rice is low in fiber and easy on the stomach. Rice cakes and rice noodles are also excellent options.
White Pasta: A classic choice, white pasta is a concentrated source of carbs. Pair it with a light, non-creamy, and non-spicy sauce.
White Bread and Bagels: These are convenient and easy to find. Use them for sandwiches or toast with jam or honey for a quick carb hit.
Low-Fiber Cereals: Opt for simple cereals like Rice Krispies or Corn Flakes, which provide carbs without a heavy fiber load.

Starchy Vegetables

These offer a great source of carbohydrates along with some vitamins and minerals. Preparing them correctly can minimize fiber content.

Potatoes: Mashed or baked potatoes (without the skin) are ideal. They are high in carbohydrates and easy to digest.
Sweet Potatoes: Similar to white potatoes, sweet potatoes are a nutrient-dense and highly effective carb source.

Simple Sugars and Fluids

In the final hours before a race, and throughout the loading phase, liquid carbs and simple sugars can provide an easy and quick source of energy, especially if solid food becomes unappealing due to volume.

Bananas and Applesauce: These fruits are excellent sources of potassium and easily digestible carbohydrates.
Fruit Juices: Drinks like apple or grape juice are quick ways to add carbs and fluids.
Sports Drinks: These are specifically formulated to provide carbohydrates and electrolytes for athletes.
Honey and Maple Syrup: Drizzled on toast, pancakes, or in oatmeal, these provide a concentrated boost of simple carbs.
Pretzels and Crackers: Salty and carb-dense, these can also help promote hydration.

What to Limit: Foods to Avoid

While nutrient-dense foods are usually encouraged, the carb-loading phase is an exception. Certain foods can fill you up too quickly or cause digestive issues right before a race.

High-Fiber Foods

High fiber intake can cause bloating and discomfort when you're trying to consume a large volume of carbohydrates. It also slows digestion, which is counterproductive during this time.

Whole Grains: Brown rice, whole-wheat bread, and high-fiber cereals are generally best left for post-race recovery.
Legumes and Beans: These are high in fiber and can cause significant bloating and gas.
Cruciferous Vegetables: Broccoli, cauliflower, and other high-fiber vegetables should be limited during the final 2-3 days.

High-Fat Foods

Fat takes longer to digest than carbohydrates and can cause you to feel uncomfortably full, making it difficult to reach your carb targets. Avoid fatty cuts of meat, creamy sauces, and rich desserts.

Carb Loading Food Comparison Table


Food Category	Typical Healthy Diet Choice	Optimal Carb-Loading Choice	Reason for Switch
Grains	Brown rice, whole-wheat pasta	White rice, white pasta	Lowers fiber content for easier digestion and higher volume.
Bread	Whole-wheat or multigrain bread	White bread, bagels	Reduces fiber to prevent bloating and discomfort.
Vegetables	Broccoli, beans, high-fiber greens	Peeled potatoes, canned corn	Limits fiber content to avoid GI issues before a race.
Sauces	Creamy, high-fat sauces (e.g., alfredo)	Light, tomato-based sauces	Minimizes fat, which slows digestion and fills you up too quickly.
Snacks	Nuts, high-fiber granola bars	Pretzels, fruit snacks, crackers, fig bars	Provides high concentration of simple carbs with low fiber.
Fluids	Water	Fruit juice, sports drinks, chocolate milk	Increases carb intake easily, especially when appetite for solids is low.

Practical Tips for Successful Carb Loading

Don't Just Supersize Your Meals: Instead of feeling stuffed with giant portions, aim for smaller, more frequent meals and snacks. This makes it easier to consume the necessary volume of carbs.
Stay Hydrated: Glycogen is stored with water, so proper hydration is crucial for a successful carb load. Increase fluid intake alongside your carb-heavy meals.
Practice in Training: Never try a new carb-loading strategy on race day. Practice with your specific food choices before a long training run to see how your body reacts.
Stick to Familiar Foods: Race week is not the time to experiment with new or exotic foods that could cause an unexpected reaction.
Don't Forget Liquids: If you struggle to eat enough solid food, drink your carbs. Juices, sports drinks, and smoothies are highly effective liquid calorie sources.

Conclusion

Carb-loading is a proven strategy for endurance athletes, but it is not a free pass to eat junk food. The key is a strategic shift to high-carbohydrate, low-fiber, and low-fat foods in the days leading up to your event. By prioritizing easily digestible options like white rice, pasta, and potatoes, and supplementing with liquid carbohydrates, you can effectively maximize your muscle glycogen stores. Remember to practice your fuelling strategy during training to find what works best for your body, ensuring you arrive at the starting line feeling energized and confident, not bloated and uncomfortable.

Frequently Asked Questions

For most athletes, a 2–3 day carb-loading phase is recommended to maximize glycogen stores before an endurance event lasting longer than 90 minutes.

Yes, simpler carbs and sugars can be beneficial during carb loading, as they are easily digestible and provide a quick energy source without adding bulk or fiber. Choose options like fruit snacks, honey, or sports drinks.

For carb loading, white rice is often preferred over brown rice because it is lower in fiber and easier to digest. This helps you consume higher volumes of carbs without causing potential gastrointestinal issues.

Yes, sports drinks are an excellent way to consume extra carbs, especially if you struggle to eat enough solid food. They also help with hydration and electrolyte balance.

Carb loading is generally not necessary for shorter events like a 5K because muscle glycogen stores are not typically depleted to the same extent as in longer endurance events. Focus on a balanced meal and proper hydration instead.

The night before the race, have a high-carb, low-fiber dinner. A classic choice is white pasta or rice with a light, tomato-based sauce and a lean protein, as it is easy to digest and minimizes the risk of discomfort.

To avoid bloating, focus on consuming easily digestible, low-fiber carbohydrates, and avoid high-fat foods. Spreading your carb intake throughout the day in smaller, more frequent meals also helps.

During the carb-loading phase, your focus should be on increasing carbohydrates and slightly reducing fat and fiber. You should maintain moderate protein intake but not increase it significantly, as excess protein can fill you up and displace valuable carb calories.