The Runner’s Guide To Simple And Complex Carb Loading

Carb loading, I’m sure you’ve heard of it. But what is it, and how should you go about it?

According to the Mayo Clinic, “A carbohydrate-loading diet, also called a carb-loading diet, is a strategy to increase the amount of fuel (glycogen) stored in your muscles to improve your athletic performance for endurance events.”

In plain language, your muscles burn glycogen for fuel, and glycogen is supplied by carb consumption. So, the more carbohydrates you eat, the more glycogen—or fuel—can be stored in your muscles for your big race, adding to your endurance.

It doesn’t matter whether you’re pounding pavement, trailblazing, or running on your home treadmill, carb loading is a widely accepted strategy for better running performance. But are you doing it correctly?

We did some research to break it down for you. Keep reading to learn the best and the worst ways to load up on those carbs as you prepare for your important race.

Not All Carbs Are Created Equal

The most basic explanation: carbs are starches, sugars, and fibers that are found in fruits, vegetables, grains, and dairy. In recent years, carbs have often been tagged with a bad reputation, especially in the weight loss industry. However, carbohydrates are essential for good health, particularly in times of strenuous physical activity, such as running.

Whether you’re training for a race or simply watching your diet, you need to know the difference between different types of carbohydrates. Basically, you can separate carbs into two categories: the good and the bad.

The Good

Carb loading – NordicTrack

Good carbs – NordicTrack

Good carbs are complex, meaning they are broken down by the body more slowly. They can offer your body more sustained energy without the crash that simple carbs tend to cause. They offer many important nutrients, including fiber. Complex carbs also help you stay fuller longer. Some examples of complex carbohydrates are:

  • Whole, unrefined grains
  • Fruits, vegetables, and legumes
  • Unrefined starches such as potatoes, brown rice, and corn

The Bad

Simple carbohydrates are often referred to as bad carbs. Why are they bad? Because they are more refined and highly processed, having been robbed of their natural nutrients and fiber. Many breads and pastas, for example, are labeled as “enriched.” That may sound like a good thing, but it really means that the good stuff has been removed as part of the refining process, and there has been some attempt to add some of it back in. Simple carbs are processed very quickly by the body and more easily stored as fat. You might get a quick burst of energy, but it’s usually followed by a crash as your blood sugar comes back down. Some examples of bad carbohydrates are:

  • White sugar or products containing it, such as candy or soda
  • Refined or “white” breads, pastas, or pastries
  • White rice or other refined grains

Your metabolism and digestion require carbohydrates to function properly. Plus, optimal brain function relies on glucose, which is supplied to your body by the carbs you eat. In short, your body needs carbs. While most runners eat a combination of simple and complex carbs while loading, nutrition experts recommend complex carbs for the majority of anyone’s carb intake.

How To “Load Up”

There are several different ways to go about your carb loading protocol. Generally speaking, most carb loading programs recommend a training diet high in carbohydrates—along with a lighter training schedule—for several days before the event. Here are some of the more popular carb-loading protocols:

The Ahlborg Method

This method is based on studies conducted by Bjorn Ahlborg, a Swedish physiologist. His work is worth mentioning because Ahlborg was the first to design a carbohydrate loading program after finding a direct correlation between the amount of glycogen stored in muscle tissues and athletic endurance. His method involves 3 or 4 days of carb depletion, followed by 3 or 4 days of carb loading. It also includes a suggested training schedule. Your basic Ahlborg plan would look like this:

  1. An exhaustive run—90 minutes or more—one week prior to the race.
  2. A very low-carb diet—around 10% carbs—for the next 3-4 days with light training.
  3. A very high-carb diet (around 90%) for 3-4 days before the event with continued light training.

More about Ahlborg’s original study and its 1964 publication can be found here.

Fortunately for carb-loving runners, more recent research indicates that you can build up your glycogen stores for a race without the initial period of severe carb restriction, as Ahlborg recommended. Here are some of the most popular carb loading methods:

The Long Taper

This method recommends conducting your final long training session 3 weeks before the race (after you’re well prepared through your usual training program, of course). For this week, you will continue a moderate training schedule of 80-90% of your maximum weekly mileage. However, by 2 weeks before race time, you should really start tapering off by listening to your body. Take this opportunity to practice the pace you’ll be using during the race, but keep your workouts moderate.

During your tapering period, shoot for 3 to 5 grams of complex carbs per pound of your body weight, along with a reduced fat intake since your body’s demand for energy will be lessened.

For example, if you weigh 150 pounds and choose to eat 4 grams of complex carbs per day, you’d be consuming 300 grams of carbohydrates on a daily basis during your taper period. Because of your reduced training, the extra carbs will allow you to build up your glycogen stores.

The 6-day Protocol

This strategy is more condensed than the long taper. Six days before your event, you’ll conduct your longest, glycogen-depleting workout. For this session, plan on adding a few minutes of intense sprinting to further deplete glycogen stores and allow for re-loading through diet.

Carb loading – NordicTrack

Complex carbs – NordicTrack

For the next 3 days, aim to eat 2-3 grams of carbohydrate per pound of body weight while you taper your training to rest up and hold onto more glycogen stores. Three days before the race, reduce your training even further, or rest completely. During this time, increase your carb intake to 4.5 grams per pound, and keep your diet low in fat.

The Rapid Load

The rapid loading method is just as it sounds. Rather than tapering your workouts in the weeks before the race to enhance glycogen storage, this plan is focused on a 24-hour carb-loading period. This method can prove useful if you feel your training has been insufficient and you need those last few weeks. Or perhaps you simply feel you perform better without tapering.

To use this strategy, perform your final glycogen-depleting training session 24 hours before your race. Immediately after your workout and continuing throughout the day, consume a very high-complex carb diet of 5 to 6 grams per pound of body weight. Also, drastically reduce your fat intake.

How you decide to carb load could depend on many factors. One main factor is the length of the race. For example, for a 5K, perhaps all you need is a breakfast with plenty of complex carbs, and a good snack or energy chew right before race time.

For a longer race, such as a marathon or half, you could consider the above methods. Carb loading is an individual thing, so it might take some trial and error with different races to find which method works best for you.

Runner Beware

While carb loading is definitely a useful tool for competitive runners, there are several mistakes that should be avoided. Here are a few of the more common ones.

  1. Keeping it too simple – Just because you’re carb loading doesn’t mean you should load up on candy, cookies, and soda. Remember, your body is in for a long race and will need plenty of nutrients to fuel your training and recovery. Simple carbs can have an adverse effect and significantly decrease your endurance.
  2. Eating too much fiber – While fiber is a good thing, some runners make the mistake of eating too much of it too close to race time. The last thing you need during your 26.2 is a stomach cramp or a case of “runner’s trots“. Chances are you already know how much fiber your stomach can handle, so don’t overdo it, especially within 24 hours of race time.
  3. Skipping your final load – The morning of a race, you might be nervous or feel like eating something will slow you down. But your muscles really need that final boost of glucose to keep fatigue at bay and ensure a good start. Although, you don’t want to down a bowl of oatmeal and a banana at the starting gate, don’t skip out on your body’s last chance to fuel up before your big moment.

Time to Eat

Carb loading – NordicTrack

Carb loading – NordicTrack

While carb loading isn’t an excuse to eat junk, it does give you plenty of opportunities to explore in the kitchen and eat some of your favorite foods. Thankfully, great carb-loading recipes, such as pasta, abound on the Internet. Need a little help planning things out? There are even sample carb loading meal plans available to get your ideas flowing.

Go Carb It Up

As you can see, there are many ways to load up on carbs in preparation for a race. Try different methods, ask more experienced peers, or get advice from your doctor or trainer to learn what works best for you.

Done correctly, carb loading can have a significant impact on your ability to perform well in a race. Talk to your doctor or trainer for specific questions about your body. They can help you decide how to best train and prepare for your next event.