What Every Weightlifter Should Know About Glycogen

You’ve probably heard that you need to eat plenty of carbs to maximize your ability to gain muscle and strength, but why is this the case?

Here’s how the logic breaks down: 

1. The primary source of fuel for your muscles during intense exercise is a form of carbohydrate stored in the body known as glycogen (pronounced gly-co-jen).
2. Eating carbs increases your glycogen levels, which allows you to do more volume (sets, reps) and intensity (weight) in your strength workouts. 
3. Doing more volume and intensity in your workouts is ultimately what leads to greater muscle and strength gains.

And by and large this is correct.

If you want to build muscle and strength as quickly and efficiently as possible, you want to keep your glycogen levels higher rather than lower, and the only way to do that is to eat a high-carb diet.

What is glycogen, though, and where is glycogen stored in the body? How does it improve your muscle mass and body composition? How do you maximize your glycogen levels? 

This article will give you the answers to all of these questions.

Table of Contents

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• What Is Glycogen?
• What Is Glycogen Synthesis?
• Where Is Glycogen Stored?
• How Glycogen Affects Body Composition
• What Are the Signs of Low Glycogen Levels?
• How to Increase Your Glycogen Levels
• What Are the Best Foods for Increasing Muscle Glycogen?

What Is Glycogen?

Glycogen is a form of stored carbohydrate in the body.

It’s formed by linking glucose molecules in chains of about 8-to-12 molecules in length, which are then bonded together to form large lumps, or granules, of over 50,000 glucose molecules. 

These glycogen granules are stored in your muscle and liver cells until they’re broken down and used for energy, primarily during exercise. 

What Is Glycogen Synthesis?

Glycogen synthesis refers to the creation and storage of new glycogen granules. 

To understand how and why glycogen is created, it’s important to understand how your body digests and stores carbohydrate.

After eating a meal, your body breaks down the protein, fat, and carbs into smaller molecules. Protein is broken down into molecules called amino acids, fat is broken down into molecules called triglycerides, and carbs are broken down into molecules of a simple sugar called glucose.

It’s possible for the body to convert protein and fat into small amounts of glucose, but this process is very inefficient and only produces enough glucose to power basic bodily functions—nowhere near enough to fuel intense weightlifting. It also only revs up when glycogen levels are already low, which is why you must consume carbs to produce a significant amount of glucose.

The body can only store about 4 grams (one teaspoon) of glucose in the blood at any time, and if levels rise too far above this range the excess glucose can damage nerves, blood vessels, and other tissues. If glucose levels stay elevated for too long, well, that’s a sign it’s time to chat with Wilford Brimley about diabeetus . . . 

To prevent this from happening, the body uses several mechanisms to pull glucose out of the bloodstream. 

The primary way the body disposes of this excess glucose is by packaging it into glycogen granules which can then be safely stowed away in muscle and liver cells. Then, when the body needs extra glucose in the future, it can convert these glycogen granules back into glucose and use them as needed.

Where Is Glycogen Stored?

Glycogen is primarily stored in muscle and liver cells, although trace amounts are also stored in brain, heart, fat, and kidney cells.

Specifically, glycogen is stored in the liquid inside of cells referred to as cytosol. 

Cytosol is a clear liquid comprised of water and various vitamins, minerals, and other substances that gives cells structure, stores nutrients, and helps support chemical reactions within cells.

After being stored in the cytosol, glycogen floats around until it’s broken down into glucose, which is then gobbled up for energy by the mitochondria—the “power plants” of the cell. 

Most people can store around 100 grams of glycogen in their livers and around 500 grams in their muscles (600 grams total), although people with more muscle mass and training experience can store considerably more than this.

Your body uses the glycogen stored in your liver as an immediate source of energy to fuel your brain and perform other bodily functions throughout the day.

Your muscle glycogen, though, is generally used by whatever muscles are contracting during exercise. For example, if you’re doing squats, then the glycogen stored in your quadriceps, hamstrings, glutes, and calves will be broken down into glucose to fuel the exercise. 

How Glycogen Affects Body Composition

When it comes to losing fat and building muscle, carbs (and by extension, glycogen) get a bad rap.

Eat too many carbs, and it will be impossible for you to improve body composition, or so many claim. Many “experts” also assert that carbs don’t help you build muscle, so it would seem they’re all cons and no pros.

This is wrong.

You can lose fat and build muscle following a low-carb diet, but you’ll likely make progress as fast or faster if you follow a high-carb diet instead. And as you can guess, the reason largely has to do with muscle glycogen.

Glycogen and Muscle Gain

If you want to build muscle as quickly and efficiently as possible, you want high muscle glycogen levels for two reasons.

1. Higher glycogen levels let you train harder.

The primary driver of muscle growth is progressive tension overload, which refers to increasing the amount of tension your muscles produce over time. The most effective way to do this is by doing more reps and sets with heavier weights over time. 

This kind of training quickly depletes your glycogen stores, though, and when this happens, your weightlifting performance tanks. 

So, indirectly at least, having higher levels of muscle glycogen helps you build muscle faster.

2. Higher glycogen levels improve recovery.

When it comes to building muscle, how well you can recover from your training is just as important as the workouts themselves.

Low muscle glycogen levels are associated with overtraining, and low-carb diets, which deplete muscle glycogen, increase cortisol and reduce testosterone levels in athletes.

Low-carb diets also reduce insulin levels. In addition to helping store nutrients, insulin also has powerful anti-catabolic properties. This means that insulin decreases the rate at which muscle proteins are broken down, which creates a more anabolic environment that’s conducive to muscle growth.

Maintaining high muscle glycogen levels also improves the post-workout genetic signaling related to muscle growth and repair, which likely leads to greater muscle gain over time.

It would be a stretch to say that boosting your muscle glycogen levels directly causes muscle growth, but it probably helps you bounce back faster from your workouts and thus gain more muscle in the long run.

Glycogen and Fat Loss

If you’re a regular around these parts, you probably know that low-carb diets aren’t superior to high-carb diets for losing fat.

That said, you may have heard that you can lose fat faster if you deplete your glycogen levels, and that this is especially true when you get close to 15% body fat as a man or 25% as a woman. Proponents of this idea say that by exhausting your muscle glycogen, you force your body to burn fat for energy instead.

Not only is this not true, doing so can make it harder to hold onto your muscle mass while cutting (and thus improve your body composition, which is really what you’re after). 

If you cut your carb intake and, by extension, your glycogen levels, you’ll perform poorly in your workouts, recover slower, and likely lose some strength and muscle mass, all of which makes it harder to get the body you want.

Thus, maintaining higher muscle glycogen levels won’t make you lose more fat, but it will likely help you avoid losing muscle by allowing you to train with heavier weights and higher volumes during your cut.

What Are the Signs of Low Glycogen Levels?

There are a few telltale signs that your muscles are low on glycogen:

• Your workouts feel awful.

If you’re getting enough sleep and are following a sensible workout routine, and suddenly every weight feels three times heavier than it should, you’re probably low on glycogen.

This is particularly true if you feel worse the longer you’re in the gym. Remember, glycogen is your main source of fuel during weightlifting, so the longer you train without adequate fuel, the harder it’s going to feel.

• You lose several pounds overnight.

Every gram of muscle glycogen is stored with 3-to-4 grams of water.

A pound is 454 grams, so if you eat 110 grams of carbs (about three cups of cooked pasta), you can gain about a pound of total body weight.

On the flipside, if you burn through the majority of your glycogen stores, you can also lose several pounds in a matter of hours.

While that’s gratifying in the short-term, it can also be a sign that you need to replenish your muscle glycogen.

There are other things that can cause you to lose or gain water weight, but changes in glycogen levels tend to be the primary factor.

• You struggle to get a “pump” in the gym.

As glycogen is primarily stored in your muscles, boosting your muscle glycogen levels can also make your muscles appear larger and feel thicker (this is one of the reasons bodybuilders often eat more carbs immediately before a competition). 

This is particularly apparent when you get a pump during a workout, which makes your muscles temporarily swell and grow larger thanks to an increase in blood flow. 

Although you can get a pump without high glycogen levels, your muscles will generally look smaller because they’re drained of carbohydrate and the water that comes with it.

How to Increase Your Glycogen Levels

One large high-carb meal isn’t enough to keep your glycogen levels elevated.

Glycogen is always being broken down and regenerated, which is why you have to maintain a relatively high daily carbohydrate intake to keep your muscles topped off.

How high, exactly?

If you’re trying to get stronger and build muscle, then you want to eat around 1-to-3 grams of carbs per pound of body weight per day.

If you want to lose fat, then your carb intake will largely be dictated by how many calories you have left after setting your protein and fat targets. For most people, this will work out to somewhere around 1-to-1.5 grams of carbs per pound of body weight.

If you also do cardio in addition to weightlifting, you’re going to burn through far more muscle glycogen than the average gym goer. You may need as much as 4-to-5 grams of carbs per pound of body weight to keep your glycogen levels full.

And if you participate in endurance sports like cycling, running, or rowing, your meals should be chock-full of carbs. A recent report conducted by Asker Jeukendrup at the University of Birmingham sheds light on how astronomically high your carb needs are during endurance training. Jeukendrup (who’s an accomplished Ironman triathlete), concluded that if you’re training intensely for more than two or three hours at a time, you should try to consume around 90 grams of carbs per hour. That’s about 1 large bagel every 30 minutes. 

The bottom line, though, is that if you want to maximize your glycogen levels you want to eat as many carbs as you can after ensuring you’re getting enough protein and fat every day.

What Are the Best Foods for Increasing Muscle Glycogen?

As glycogen is composed of glucose—a kind of carbohydrate—the best foods for increasing muscle glycogen levels are those that are high in carbs. 

Some people resort to refined carbs like breakfast cereal, white bread, and high-carb snacks like pretzels, Pop-Tarts, and the like to boost their muscle glycogen levels, but this isn’t a great idea.

While any food high in carbs will get the job done, it’s best to focus on whole, minimally processed, nutrient dense sources of carbs for a few reasons: 

1. Food doesn’t just provide calories, carbs, protein, and fat. It also (should) provide micronutrients like vitamins, minerals, and phytonutrients to support health and vitality. 
2. This kind of diet might work when you’re bulking or extremely active, but it also ingrains poor eating habits that can become hard to break once you switch back to cutting or become less active. 

Here are some of my favorite high-carb foods for topping off glycogen levels: 

• Sweet potatoes
• White potatoes
• Bananas
• Strawberries
• Grapes
• Apples
• Mango
• Blueberries
• Oats
• Barley
• White, brown, and black rice
• Dried fruit
• Whole grain bread and pasta
• Beans and peas