Carb Loading 101 for Runners & Triathletes

When I was speaking at FitBloggin this past week (recap to be posted soon!), the topic of carb loading came up in my session.  If you’ve ever wondered about whether you need to carb load and how to do so, this carb loading 101 post should help you!

1.  What is carb loading?

Carbohydrate loading refers to the strategy of eating high carbohydrate meals in the days leading up to the race.  While we typically envision piles of pasta, carb loading can be done using many different types of foods.

2.  Do you need to carb load for every race?

No!  Carb loading is only beneficial when you will be competing in events lasting longer than 90 minutes.  Anything shorter than that and it won’t play a role in performance.  For those long events, though, research shows carbohydrate loading may result in up to 20% longer time until fatigue.

3.  Why does carb loading help in longer races?

Let’s imagine a sponge.  You put it under the sink for a few seconds with the sink turned on super low – like at a drip- drop pace.  The sponge is still dry in some places and only slightly saturated in others.  Now, squeeze the sponge.  Not much water comes out right?

Imagine the same sponge, but you have completely saturated it with water.  When you go to squeeze it, you are able to squeeze out a large amount of water.

This is comparable to fueling properly in the days leading up to a race.  If you only eat minimal amounts of carbohydrate, you are not putting enough energy in your muscles.  When your muscles begin working in the race, the glycogen supply will run out quickly.  On the other hand, if you eat properly in the few days leading up to the race, you fully saturate your muscles (like that sponge) with all the glycogen that it can hold.  This means you will be as prepared as possible at the starting line.

4.  How much should I eat leading up to the race?

While many people envision carb-loading as stuffing themselves with as much as possible, this is not the case.  Actually, if you are eating a proper athletic diet that is rich in healthy carbohydrates – you won’t have to alter your eating plan too much in the week leading up to the race.  The reason?  Tapering!

If you are tapering your workouts the way that most coaches recommend, you’ll have a significant drop in training volume the week before your race.  Because of this, you are burning less calories – and using less glycogen – throughout that week.

So, if you continue eating a standard training diet – one that contains a variety of healthy carbohydrate choices often throughout the day – you are essentially carb-loading just by doing that.  The proportion of carbohydrate you’re eating compared to what you’re burning is now greater (since you’re burning less), so you are able to saturate those muscles with glycogen in advance of your race.

And then in the 2-3 days before your race, you can slightly increase carbohydrate intake (up to approximately 70% of your daily calories) to ensure your muscles are fully stocked with glycogen.

Another way to think of this is the plate method.  Your normal everyday plate might be divided up into 1/2 veggies and fruits, 1/4 lean protein, and 1/4 grains/starchy vegetables.  The 2-3 days before the race, you may shift that so most of your meals contain 1/4 veggies, 1/4 lean protein, 1/2 grains & starchy vegetables – and maybe a serving of fruit on the side as well.

5.  What are the best carb loading foods?

The best foods are going to be any foods that you enjoy, that sit well in your stomach, and that are generally healthy.  The type of carbohydrate is not as important as the amount.

Examples of carb-rich foods (but by no means an extensive list) for an athlete’s diet include:

• Grains* – pasta, rice, pancakes, cereal, bread, oatmeal, quinoa, barley
• Fruits – apples, bananas, oranges, watermelon, raisins, dates, pears, plums, peaches, pineapple, kiwi
• Starchy Vegetables – potatoes, sweet potatoes, corn, peas, squash
• Dairy (and dairy substitute) products – yogurt, milk, chocolate milk, sweetened almond milk/cashew milk/soy milk
• Beans** – black beans, kidney beans, chickpeas, black eyed peas, white beans, red beans

From the list above, choose a variety of different types of foods.  The variety helps decrease the risk of problems sometimes associated with any one food choice, like diarrhea from only carb loading with fruit or constipation when only carb loading with refined grains.

*It’s wise to choose whole grains for your everyday diet – but the night before and the morning of your race, you may find it better to choose refined (white) products.  These have less fiber in them which can minimize the risk of GI problems.

**Similarly, beans are great early in the week before a race, but you may want to skip them the night before if you find that the additional fiber creates GI upset on the course.

6.  Any other tips?

Don’t try any new foods or foods you don’t eat regularly because you think that’s what will make you successful.  If you never eat pasta and have a giant plate the night before your race, you may find yourself a little bloated or uncomfortable.  Stick with familiar foods!

Share with me:  Did you find this post helpful?  Have you ever carb loaded for a race before?

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Chrissy Carroll

Chrissy Carroll is a Registered Dietitian and USAT Level I Triathlon Coach. She specializes in sharing nutrition and fitness tips, as well as recipes, for runners, triathletes, and active women.Chrissy holds a Bachelor's Degree in Nutrition, a Masters Degree in Public Health, and is also an ACSM Certified Personal Trainer.

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