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Carb Loading: What Is It and Why It's Important for Runners

Woman carb loading

When I first started running, I had this impression that carb loading meant enjoying a big pasta dinner the night before a race. Even if I was running a 5k – I thought I was supposed to “carb up” the night before. But I found myself feeling fatigued and sluggish with GI issues on race day.

As I’ve gotten more experienced with running over the years and more educated about nutrition, I am much more confident with carbohydrate loading and how to fuel properly in a way that feels good. A large piece of the 1:1 coaching I provide to runners includes education around nutrition, specifically carb loading and how it can fuel performance and recovery.

Does everyone need to carb load? No. Carb loading is the most vital when training for longer races; half marathon, full marathon, and anything beyond that. If you’re running a 5-10k, you don’t need to worry too much about “carbing up” the night before a race.

Typically, carbohydrate loading should be considered when training or racing for 90 minutes or longer.

Let’s talk about what carb loading is, why carb loading is important and how to carb load in a way that feels good.

What is Carb Loading and Why is it Important?

Your body needs all of the macronutrients; fats, proteins and carbohydrates. But carbohydrates are the macronutrient that is used for energy during endurance events. This is why we carb load!

Carb loading refers to increasing your carbohydrate intake in the days leading up to an event, also associated with a decrease in training volume (also known as tapering). Notice I said days leading up to – not just the night before. This is a critical piece of importance when it comes to carb loading properly.

To fill muscle glycogen stores appropriately and in a way that feels good to your body, runners should consume increased levels of carbs multiple days ahead of an event.

Woman carb loading

Glycogen stores refer to the carbohydrates that are stored in the muscle. Endurance athletes rely on their glycogen stores to provide them with energy and fuel during training or races longer than 90 minutes. Ninety minutes is roughly the length of time it takes for typical stores of muscle glycogen to begin to run low.

If your glycogen stores are empty, you will run out of energy and experience fatigue – ultimately preventing you from doing your best during an event.

How to Carb Load

Now that we understand what carb loading is and its importance, let’s discuss how to carb load.

There’s no right answer on the exact amount of carbohydrates that should be consumed during this phase of training. It’s often suggested to consume 3 - 5g of carbohydrates per pound/body weight but as with most other parts of training, you must find what works best for you.

During the carb loading phase, the carbohydrates you consume should be easily digestible. Complex carbohydrates are important as well as avoiding meals that are too heavy or high in fat (like a creamy pasta). Ultimately, increasing the amount of carbohydrates you consume with each meal will help you get to your overall carbohydrate goal for this phase.

Fruit toast for carb loading

It’s important to try out carb loading during training – before long distance training sessions or even minor events/runs you have during training. This will allow you to become comfortable and confident with the types and size of foods and drinks necessary to successfully carbohydrate load.

A lot of the work I do with runners as a running coach is educating on the importance of a proper carb loading strategy as well as ensuring they are testing their strategy during training.

Now, back to pasta. When it comes to carb loading properly, our only option is NOT to consume a big bowl of spaghetti (although delicious). There are several foods that have high or higher levels of carbohydrates that are easy on the stomach and nutritious.

A few examples of foods great for carbohydrate loading





Fruit Smoothies


Sweet Potatoes


Whole grain bread


Oatmeal with blueberries for carb loading

Everyone will have unique needs which is why it’s vital to test your carb loading strategy during training so that by race day, you’re confident in your carb loading plan and know how your body will respond.

Nutrition is a vital piece of training for an endurance event. Carb loading effectively can help you feel your best on race day and lead to increased performance.

One of the biggest reasons I became a running coach is to help others understand and find confidence in their training plan, as there are so many moving pieces it’s difficult to manage it alone. If you find yourself overwhelmed with your training plan, nutrition and putting all the pieces of training together, schedule a free introductory call here. We will chat for about 30 minutes about your running goals, challenges you’re facing, and I can share some actionable strategies for how to best overcome them.

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