Glycogen Supercompensation Explained: What It Is + Training Guide

Last Updated:

After you’ve been running for some time, most runners become familiar with all sorts of terms related to exercise physiology. From lactate threshold to glycogen, there’s a bevy of useful terminology and concepts to learn that can help you understand how to optimize performance.

Supercompensation, usually called glycogen supercompensation, is not typically discussed among recreational runners, though marathoners might be familiar with the related concept of carbo-loading.

Indeed, the decades-old practice of enjoying a big bowl of pasta the night before a marathon is based on the very concept of glycogen supercompensation—or the ability to increase your muscle glycogen stores to improve athletic performance.

In this article, we will discuss what glycogen supercompensation is and how to do supercompensation training to run faster and longer for your next marathon.

We will discuss: 

  • What Is Glycogen Supercompensation?
  • Why Is Glycogen Supercompensation Important for Runners?
  • How to Achieve Glycogen Supercompensation for Endurance Performance
  • Do You Have to Stop Running to Maximize Glycogen Supercompensation?
  • How Much Glycogen Supercompensation Can Runners Expect?
  • Does Glycogen Supercompensation Improve Performance?

Let’s get started!

A person eating pasta.

What Is Glycogen Supercompensation?

Glycogen supercompensation refers to increasing your muscle glycogen storage above your baseline levels for the purpose of improving endurance exercise performance.

Studies suggest that glycogen supercompensation occurs by increasing the number of glycogen molecules stored in the muscle rather than increasing the size of the glycogen molecules in the muscle.

Why Is Glycogen Supercompensation Important for Runners?

Let’s take a step back and start with the basics. Glycogen is the storage form for carbohydrates in the body.

When you eat any food that contains carbohydrates, such as fruits, whole grains, and even legumes, the carbohydrates are broken down into glucose and other simple sugars.

Your blood glucose concentration increases as the sugar is transported through the bloodstream to tissues that need energy.

Your brain, liver, skeletal muscles, and heart, for example, can take up the glucose through receptors and metabolize it for energy.

However, any glucose that is not needed right away can be shuttled to the muscles and liver for storage. There, it is synthesized into larger molecules known as glycogen.

People running a marathon.

According to the Academy of Nutrition and Dietetics, an endurance-trained athlete can store up to 1,800 to 2,000 calories of fuel as glycogen in the muscles and liver. Smaller runners might store closer to 1,500 calories or so.

Consistent endurance training actually induces adaptations in your muscles to reach these improved capacities.

This amount of stored glycogen can fuel about 90 to 120 minutes of running or other vigorous activity, depending on your body size and the intensity of your workout. 

After you run, as long as you are refueling with a high-carbohydrate diet, these levels can come back up to baseline within 24 to 48 hours after exhaustive exercise.

However, most marathoners can attest that just having 90-120 minutes of carbohydrate-based energy isn’t going to suffice for a longer event.

It can be difficult to take in enough calories relative to your energy output.

People running a marathon.

Even if you try to stay on top of your fueling strategy during your race, refueling with simple carbohydrates to top off your blood sugar every 15-30 minutes, you can find yourself “bonking” or “hitting the wall” when your glycogen stores are depleted.

This is experienced as the dreaded feeling of sudden fatigue and heavy legs.

Essentially, muscles can generate the ATP (cellular energy) they need to allow you to keep running from carbohydrates and fats (and, to a lesser degree, proteins).

Glycogen (carbohydrates) can be oxidized for fuel more quickly, which means that your muscles can create the energy quickly enough to keep up with the demand for ATP. 

This means you can keep running at a faster pace.

In contrast, fat is oxidized more slowly, so your muscles can only keep up with generating energy at the rate they need it when you are running at an easy pace or exercising at a low intensity.

This is why your pace can drastically slow down once your glycogen stores are empty.

The entire premise behind glycogen supercompensation is that through supercompensation training, you can “overfill” your glycogen stores above their normal capacity, giving you more carbohydrate-based energy onboard to fuel faster running or more intense exercise.

By achieving glycogen supercompensation, you can delay hitting the wall because you increase the storage of carbohydrates beyond that 1,800-2,000 calorie capacity you’ve already achieved by consistent endurance training.

A variety of carbs.

How to Achieve Glycogen Supercompensation for Endurance Performance

In the context of glycogen supercompensation, supercompensation training refers to altering your exercise and nutrition routines leading up to an endurance event to achieve glycogen supercompensation.

Some runners assume this only involves carbo-loading, but maximizing your glycogen supercompensation effects is actually more involved than that.

According to research, the most effective approach to glycogen supercompensation training is to deplete your glycogen stores as much as possible before trying to over-sate them.

This is usually accomplished by a 6-day protocol involving a hard exercise bout to exhaustion followed by three days of following a low carbohydrate diet to fully deplete glycogen.

A person eating a granola bar.

Then, exercise is tapered way back or ceased altogether for three days in conjunction with following a high-carbohydrate diet.

This type of glycogen supercompensation protocol is generally thought to yield the best results and maximize your muscle glycogen concentration.

An older study found that not only do endurance-trained subjects have higher normal baseline levels of muscle glycogen than untrained subjects but also that the most effective glycogen supercompensation protocol for both trained and untrained subjects involves performing a bout of exhaustive exercise, then tapering exercise while restricting carbohydrates for 3 days, then eating a high carbohydrate diet for 3 days. 

This carb-loading protocol results in significantly higher muscle glycogen storage than just reducing training and increasing carbohydrates.

In short, the exhaustive exercise bout and carbohydrate restriction phase were both critical parts of achieving enhanced glycogen storage over baseline levels.

People running a marathon.


One study found that it might not be necessary to be as restrictive during the “low carbohydrate” diet phase.

In fact, the glycogen supercompensation effects were similar, whether the athletes followed a 3-day diet that contained only 15% of the calories from carbohydrates (the typical recommendation) or a more moderate diet containing 50% of the calories from carbohydrates.

Both diets were preceded by the standard approach of completing an exhaustive bout of exercise and then followed by 3 days of a high-carbohydrate diet. 

The high-carbohydrate diet provided 70% of the calories from carbohydrates.

So, how much carbohydrate should you eat during the “high-carbohydrate” phase of glycogen supercompensation protocols?

Most experts say the carbo-loading phase of glycogen supercompensation training should involve a diet that provides about 70% of the calories from carbohydrates, 15% from protein, and 15% from fat.

According to the Mayo Clinic, you should aim for 8-12 grams of carbohydrates per kilogram of body weight for 1-3 days before the event.

A bowl of pasta.

Do You Have to Stop Running to Maximize Glycogen Supercompensation?

According to research, the exhaustive exercise to kickstart the glycogen depletion phase significantly increases your glycogen supercompensation results.

The good news is that the same study found that it might not be necessary to cease exercise altogether during the carbo-loading for three days.

Results were similar for subjects who tapered their workouts during the 3-day high-carbohydrate diet to 20 minutes at 65% of VO2 max and those who stopped exercise entirely.

Many runners don’t want to cease running completely for three full days before a race, so this moderate approach can be a good alternative.

People running a marathon.

How Much Glycogen Supercompensation Can Runners Expect?

One study suggested that the majority of glycogen is stored in skeletal muscle (approximately 400 g, or 1,600 calories worth) and that there’s a “set-point” for glycogen concentration in muscle around 1.5 g/100 g muscle. 

Glycogen supercompensation training may effectively disrupt the normal efficient feedback-regulation of glycogen synthase, which keeps glycogen levels in muscles tightly controlled at this level, allowing glycogen synthesis to increase significantly such that the muscle glycogen concentration rises to 4 g/100 g of muscle.

Another study found that successful glycogen supercompensation training with the standard 6-day protocol increases muscle glycogen by 1.79 times above baseline.

If you normally store about 1,800 calories, this glycogen supercompensation level can bump you up to over 3,200.

Another study confirmed that a carbohydrate dosage of 12 grams/kg of body weight per day for three days, when coupled with a simultaneous cessation of training, was effective at inducing glycogen supercompensation in endurance-trained men and women. 

In fact, this high-carbohydrate diet and exercise taper increased glycogen levels by 78% over baseline for men and 82% in women.

People running fast.

Does Glycogen Supercompensation Improve Performance?

Evidence suggests that elevated starting muscle glycogen levels (glycogen supercompensation) will indeed delay fatigue by approximately 20% in endurance events lasting more than 90 minutes. 

This means glycogen supercompensation in runners or endurance athletes can extend “time to exhaustion” by about 20%.

For example, if you can run 90 minutes at 80% of your VO2 max with normal muscle glycogen levels, with glycogen supercompensation in muscle tissue, you might be able to run for 108 minutes without needing to stop.

This is thought to be because exhaustion during endurance exercise usually coincides with critically low levels of muscle glycogen (less than 25 mmol/kg wet weight).

Additionally, glycogen supercompensation has been shown to improve endurance performance in which a set distance is covered as quickly as possible (such as in marathons and time trials) by 2 to 3%.

This may not sound like a ton, but it can be the difference between getting a Boston Marathon qualifying time (or other PR) and just having a decent race.

If you run a 3:30 marathon, a 3% improvement will have you finishing 6 minutes and 20 seconds faster, crossing the line in 3:23:40. That’s a pretty big difference!

Need some ideas to cook up some high-carb meals to start your carbo-loading? Check out our 11 Great Carbohydrate Sources For Runners.

A variety of carbs for glycogen supercompensation training.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.