Why Do Athletes Carb Load?

Carb loading is a strategy embraced by athletes worldwide. A lot of people think carb loading just means having a cheat meal like a huge bowl of mac n' cheese or a pizza. While you could consider that to be "carb loading" It's definitely not the type of carb loading we're talking about! Real, effective carb loading is far more precise and calculated.

It's a nutritional strategy that involves manipulating your carbs and training. But, what does carb loading look like? Why do athletes carb load in the first place? Can you use carb loading to help you reach your goals? I'm here to give you the answers to these questions and more! Before we do that though, we have to cover what carbohydrates are.

What Are Carbohydrates?

I’m sure you’ve heard of carbs before, but not everyone really knows what they are. I can tell you this … they’re not bad for you like many will lead you to believe! Carbohydrates are one of the 3 macronutrients that have calories and give us energy. The other two are protein and fat. While they all give us energy, carbs serve as our body’s favorite source of energy.

Carbs are classified into three main types. These are sugars (simple carbs), starches (complex carbs), and dietary fiber. Each of these types plays a unique role in nutrition and health.

For example, simple carbs from sources like fruit and sweets can give us very quick access to energy.  They are rapidly digested and offer a swift spike in blood sugar levels. This makes them ideal during or right before high-intensity activities. Complex carbs, on the other hand, break down a little slower. These include starches found in foods like whole wheat bread, pasta, or sweet potatoes. These carbs take longer to break down, so they provide a more sustained release of energy. They can be more helpful for longer workouts because we won’t burn through them as quickly. Last but not least, we have dietary fiber. Fiber is a type of carbohydrate that your body can't actually digest. When it’s present in other carb sources, like vegetables, we absorb the carbs more slowly.

Although it doesn’t directly provide energy, fiber is crucial for gut health. Fiber can also help regulate blood sugar levels by slowing the absorption of carbs. Together, these carbohydrates form a crucial part of a healthy diet. If you’re looking for carbs to add into your diet, think about adding them in from sources like these:

• Fruits like apples, oranges, berries, and bananas

• Starchy vegetables like potatoes, sweet potatoes, peas, and corn

• Whole grains like bread and pasta

• Oatmeal

• Legumes like beans and lentils

• Rice

If optimal performance is what you’re looking for in exercise, carbs like these are essential! 

Now, you should have a better idea of what carbs are, and some good sources of them. We still need to answer the question though: “Why do athletes carb load?” We’ll get there. First, let me cover exactly what carb loading is.

What Is Carb Loading?

Carb loading is a nutrition strategy aimed at maximizing glycogen stores. Glycogen is a stored form of carbohydrates in our bodies. We store glycogen in our muscles, our liver, and in our brain. There’s not much stored in our brains, but we can store a whole lot in our muscles! These carb stores in our muscles are the main source of energy we use during intense exercise. Our liver stores aren’t as big, but they play a role in regulating our blood sugar.

When we exercise intensely, we may end up using blood sugar for energy too. Liver glycogen is mainly used to keep our blood sugar within normal ranges when this happens. So, if we need glycogen to give us energy during competition, the more we have the better and longer we can perform ... Right? Correct. The more glycogen in your muscles and liver, the more work you can do before you run out of energy.

So, is there a way to ensure we store more glycogen than we currently have? Yes, and that’s why athletes carb load! Carb loading is basically a strategic approach to increasing glycogen storage in muscle through nutrition and training adjustments.

Allow me to give an example of a carb loading protocol. The process begins several days to a week before the competition. First, you have to deplete your glycogen stores. To do this, athletes up the intensity of their workouts while lowering their carb intake for a few days. This can help them to really deplete as much glycogen as they can.

Our bodies want glycogen, and don’t like running low on it. When glycogen stores do run low, our bodies want to increase the amount of glycogen we can store in the future. That way, our body won't have to get so close to running out again. Let’s say for those first few days you only eat 1.5 grams of carbs per kg of bodyweight. You work out hard at the same time, and you end up using more glycogen than you store. After that, athletes usually lower their exercise intensity for a few days, and eat a lot more carbs. So, in those next 3-4 days, you might up your carb intake to around 8 to 12 grams per kg bodyweight.  While not working out as hard, you’ll burn through less glycogen as you do this. This allows you to continuously store more glycogen over the next few days.

This strategy allows your muscles to empty and then increase their storage capacity. If done correctly, you should end up storing more glycogen than you had before.

Why Do Athletes Carb Load?

By eating more carbs, athletes can increase the glycogen in both their muscles and liver. The idea is, the more glycogen they have for energy, the better/longer they can potentially perform. Carb loading is a common technique used before endurance events longer than 90 minutes. This can be everything from marathons to long-distance cycling and lap swimming.  That’s not to say that carb loading isn't beneficial in other athletic events though. Football, soccer, rugby, and so many others are all sports where carb loading can be used.

For example, carb loading has been shown to improve running performance while lowering fatigue. I'd argue that this can help in pretty much any physical sport. It’s also beneficial for bodybuilders. Bodybuilders aren’t exercising during their competition though. Carb loading helps them for a different reason. Bodybuilders stand on stage to show off their muscles, right? Well, the more glycogen stored in their muscles, the bigger and more full their muscles look. When it comes to bodybuilding, that can be the difference between winning and losing!

So there’s a wide range of athletes who can benefit from carb loading. It’s not a small benefit either. The advantages of carb loading can be substantial. It can enhance overall performance by maximizing energy availability and delaying fatigue. Carb loading puts you in a position to do your best in any physical competition!

Benefits of Carb Loading

So, why do athletes carb load? For all the benefits it provides for their performance! Carb loading can help support energy levels and performance, particularly in endurance events.

Enhanced Endurance & Stamina

By maximizing muscle glycogen stores, carb loading can support your muscular endurance. This increase in available energy allows you to sustain higher performance for longer.  It's especially beneficial in endurance sports where maintaining a pace is crucial. This preparation could lead to lower race times and better performance measures.

Delayed Onset of Fatigue

One of the most significant advantages of carb loading is the ability to delay fatigue.  With more glycogen, your muscles have a prolonged energy supply. This reduces the likelihood of “hitting a wall" before the competition ends.

Improved Recovery Post-Exercise

Post-workout recovery is just as important as the preparation leading up to it.  Carb loading can help replenish depleted glycogen stores more quickly after exercise. For those that train daily, this is a great benefit. It allows you to maintain more glycogen, and perform well in each consecutive workout. In my own personal experience, it makes a pretty big difference. Not only did I perform well the day of, but I also had more energy the following day. For those playing sports and have multiple games a week, this could give you a slight edge. If you have a basketball game today and tomorrow, you don’t only want to play well today. You want to maximize performance in both games. Carb loading could help you out a ton in that situation.

Now, I already gave you one idea of what carb loading can look like. However, there are multiple ways you can approach carb loading. Let's dive into some of the most popular methods.

Types of Carb Loading

Carbohydrate loading can be tailored to meet your specific needs and schedule.  Each of these carb loading techniques has its benefits and considerations. Which one you should choose will depend on your timeline and personal preferences. Obviously, it won't be possible to do a 6-day carb load with a race 2 days away. At the same time, you may not even want to carb load over 6 days. So, here are some of the different approaches you can take...

Classic 6-7 Day Carb Load

The classic 6-7 day carb load strategy alternates carb intake over a 6-7 day period leading up to an event. 

The first 3 days is a low-carb diet combined with intense exercise to deplete glycogen. 

The next 3-4 days then shifts to a high-carb diet while tapering off exercise to boost glycogen stores. 

This method is designed for athletes who can manage a longer prep. Not every sport allows this long between competitions.

6-Day Gradual Carb Load

This approach also spans six days. The difference is it modifies the carb intake and exercise in a more gradual manner.  Athletes begin with moderate carb intake and normal training. Then, they progressively decrease exercise intensity and increase carb consumption.  This gradual transition is less abrupt than the classic method. This can be easier for some athletes to handle. Although, they still need glycogen depleting exercise to maximize what they store (3). That goes for any protocol you choose to follow.

Classic 3-Day Carb Load

The classic 3-day carb load starts with an exhaustive workout to deplete glycogen... Just like with any other protocol. It's then followed by three days of rest combined with high carbohydrate intake.  This method is intensive and requires careful timing to ensure glycogen is filled before the event. It also allows for enough recovery time before they return to competition.

Modified 3-Day Carb Load

Similar to the classic 3-day carb load, this method includes three days of high carb intake. The difference is it omits the initial exhaustive exercise session. This approach can be ideal for athletes who don't like the depletion phase, or who may not recover quickly from it. Keep in mind, though, that the max amount of glycogen stored may not be as high. Without glycogen depleting exercise, you can still increase your energy stores. They just won’t likely increase to the same extent without that initial depletion.

1-Day Carb Load

The 1-day carb load is a quick approach where athletes consume a lot of carbs for one day without exercising.  This method suits athletes who have less time to prepare, or want a less intense carb loading regimen. It can still provide a significant boost in glycogen levels, but it won’t be as extensive as the longer methods. If all you have is one day, though, I'd say this is the way to go!

Carb Loading Tips

If you’re planning to give carb loading a try, I'm sure you want to get the most out of it. If this is the case, there are a few things I should mention before you get started.

Keep these things top of mind!

Timing Your Carb Load

For Longer Races: Start carb loading up to 7 days before an event to gradually boost glycogen levels. For Shorter Events: Begin carb loading 1-3 days prior to the event. This ensures glycogen levels can peak at the right time.  How many days you choose to carb load will depend on how much time you have until the event. It will also depend on how necessary it is for you to maximize your glycogen storage for that event.

Managing Carb Intake

Another important component to carb loading is determining how many carbs you'll need.

Daily Carb Goals: Aim for between 8-12 grams of carbs per kg bodyweight each day during the carb loading period. In pounds, this is about 3.6-5.5 grams of carbs per pound of bodyweight. Adjust this based on your current diet and the demands of your upcoming event.

Measuring & Tracking: Use a nutritional journal or a nutrition tracking app like the 1st Phorm App. This can help to accurately monitor your carbohydrate intake. You can't manage what you can't measure.

Carb Intake Adjustment: If that number seems a little high, try making your diet 70% or so coming from carbs. That should be significant enough to help you fill up your glycogen stores.

Keep in mind these recommendations are for athletes serious about maximizing glycogen. If you’re not training extremely hard, you likely don’t need to consume this much.

Selecting the Right Foods

• Focus On High-Carb, Low-Fat Foods: Go for high-carb foods that are low in fat. This could help to ease digestion and avoid discomfort. Good options include bagels, pasta, rice, and fruits.

• Eat Familiar Foods: Stick to carbs that you are familiar with to avoid digestive issues on the day of the event. Nobody wants to end up with bubble guts as they get ready to perform!

• Balanced Meals and Snacks: Disperse your carb intake across several, smaller meals throughout the day. This can make it much easier to get the amount you need.

• Eating and Drinking Carbs: If you’re having trouble eating enough carbs, try drinking them. It’s not always easy eating a bunch of carbs everyday without slamming down candy and junk food. Adding in drinks with carbs like fruit juice can allow you to eat less volume, and still get enough carbs.

• Simple vs Complex Carbs: If you have a longer carb load, the type of carb doesn’t matter that much. If you only have a day to carb up, though, then simple carbs are the way to go. They’ll fill your glycogen stores faster in 24 hours than complex carbs (3).

Adjusting Exercise & Diet

• Exercise Tapering: Reduce the intensity of your training in sync with carb loading. Train harder with less carbs at first, then lower the intensity as you increase carbs. This helps to minimize energy expenditure while maximizing glycogen storage.

• Reduce Fat Intake: To make room for more carbs, reduce your fat intake during the carb loading phase. Essentially, you’re eating less fat and replacing those calories with carbs. Otherwise, as you carb load, you’ll be eating a lot of extra calories.

Side Note: I don’t recommend anything less than 50 grams of fat a day for men. For women, I recommend staying at or above 40 grams of fat per day. Fat is an important nutrient for hormonal health and functioning.

Consulting Professionals

• Personalized Guidance: For tailored advice to your specific needs and goals, ask a pro. This could be a registered dietitian, or a certified strength and conditioning coach.