Spring race season is quickly approaching, and if you’re gearing up for a marathon, then you’ve probably heard about the magic of carbohydrate loading. But what does carbohydrate loading really mean? Think of your body as a race car before it hits the track – you want that race car to have a full tank of gas, right? Carbohydrate loading helps your body store energy so you can hit the start line with a full tank! Let’s break down how to properly load up and ensure you’re ready to crush your marathon.

What Is Carbohydrate Loading?

Carbohydrate loading is a strategy used by endurance athletes to maximize the storage of glucose as glycogen in the liver and muscles for later use. Glycogen is essential for sustained energy during prolonged bouts of physical activity, and having your glycogen stores fully loaded can help you perform at your best. This strategy also helps prevent fatigue from setting in during the race, allowing you to maintain your energy levels and push through the later miles of the marathon.

This strategy involves eating an increased amount of carbohydrates around 2 to 3 days before a big race or competition that is >90 minutes long. Carb loading does NOT mean eating an excessive amount of calories or sugary foods leading up to your race. Instead, carb loading is about strategically increasing your carbohydrate intake with the right types of foods while decreasing fat and fiber intake that could cause stomach upset or sluggishness.

Who Can Benefit From Carbohydrate Loading?

Carb loading is beneficial for individuals preparing for any long endurance event, which includes:

Marathoners (half, full, and/or ultra)
Triathletes/Ironman
Long-distance cyclers
Long-distance swimmers
Athletes with multiple endurance events in one day

how should I Carb Load?

Carb loading is more strategic than just eating a huge plate of pasta the night before your race. To effectively carb load, you should aim to consume 10-12 grams of carbohydrate per kilogram of body weight (1 lb = 2.2 kg) for 2 to 3 days before the race. For example, a 150 lb individual should aim to eat 680-815 grams of carbs per day.

If you are new to carb loading or find it difficult to consume such a large quantity of carbohydrates each day, try aiming for 8 grams per kilogram instead. You could also start your carb load a day or two earlier to ensure maximum glycogen storage.

What Should I Eat While Carb Loading?

First and foremost, stick to foods you’re familiar with. You should prioritize foods that are high in carbohydrates and low in fat and fiber. If it’s difficult to meet your carb goals through foods alone, then consider incorporating liquid carb sources like Gatorade or juice. Foods that are high in fiber (ex: broccoli, beans, raspberries) or fat (ex: avocados, cheese, fried foods) can interfere with your carb loading goals and may cause gastrointestinal discomfort on race day. Here are some examples of foods that are carb load friendly:

Although carbs are the star of the show leading up to your race, there’s no need to completely cut out protein and healthy fats. Protein is essential for muscle recovery and repair, while healthy fats help maintain a balanced diet. Instead of eliminating these macronutrients, focus on adjusting their intake. As you increase your carbohydrate consumption, temporarily reduce protein and fat to low-to-moderate amounts.

Other Tips

Be sure to stay hydrated throughout your carb load. Sufficient hydration will help your body perform at its best.
Weight gain is normal and reflective of the fact that your body is storing energy. This weight gain is temporary and means that you are adequately hydrated and fueled for your big race.

Sample Carb Loading Days

It can be difficult to visualize what 500 grams versus 800 grams of carbs looks like. Determining the carbohydrate content in some of your favorite high-carb foods can be helpful. For example, if you're aiming to consume 500 grams of carbs per day during your carb load, breaking it up into 50-gram portions throughout the day can make it easier to reach your goal. Here are serving sizes of foods commonly used during a carb load that provide ~50 grams of carbohydrate:

1 cup white rice
2-3 slices white bread
1 bagel
1 cup oats
1-1.5 cups dry breakfast cereal
2 medium bananas
~1 handful dried fruit
1/2 cup pasta
~4 graham cracker sheets
2.5 cups orange juice

The bottom line:

Carb loading is a game changer when it comes to boosting your energy for race day. We hope the tips we've shared make your carb load easier to achieve. If you’d like personalized support, feel free to reach out—we’re happy to work with you to create a carb loading plan tailored to your specific needs and preferences.

Learn more about carb loading on our instagram!

References:

Hawley JA, Schabort EJ, Noakes TD, Dennis SC. Carbohydrate-loading and exercise performance. An update. Sports Med. 1997 Aug;24(2):73-81. doi: 10.2165/00007256-199724020-00001. PMID: 9291549.
Hearris MA, Hammond KM, Fell JM, Morton JP. Regulation of Muscle Glycogen Metabolism during Exercise: Implications for Endurance Performance and Training Adaptations. Nutrients. 2018; 10(3):298. https://doi.org/10.3390/nu10030298

Carb Loading for Marathon Race Day