Why You Need Carbs to Build Muscle
Updated: Oct 5
When it comes to health and fitness, there is a lot of bad advice out there. There are two common misconceptions about body composition and diet:
1. Decrease carbohydrates for weight loss
2. Only increase protein for muscle growth
However, these two rules of thumb are not absolute truths. Carbohydrates and protein are nutrients that both play important roles in body composition, yet they both have stereotypes that aren’t 100% accurate.
If you want to gain muscle mass, then yes, you will need a lot of protein. But you’ll also need a fair amount of carbohydrates, and that shouldn’t be shocking or scary.
Protein automatically gets the credit for building strong muscles, but let’s not forget about your carb intake.
Depending on your body composition goals, you’ll need to adjust the amount and type of carbohydrates you consume.
When someone wants to lose excess weight, the first thing they do—or the first thing they’re told to do by their friend who acts as their personal trainer —is to adopt a low-carb diet. This can definitely lead to fat loss, but cutting carbs shouldn’t be a hard and fast rule in body composition, especially when it comes to gaining muscle.
Carbs usually aren’t restricted if muscle growth is the goal. It seems like weightlifters and athletes know some things about carbohydrates that the general public doesn’t: carbs aren’t the enemy to achieving your body composition goals.
Like a lot of things in life, there are carbs that will help you reach those goals and carbs that will prevent you from reaching those goals. Out of the various types of carbs, complex carbohydrates play a largely important role in building muscle mass.
Carbohydrates and Building Muscle Mass
Think about it: building anything takes a lot of time, energy and resources. Building muscle is no different. The body requires a lot of energy to power through workouts that result in bigger, stronger muscles. Where does the body get most of that energy? Usually from carbs.
Energy from Complex Carbohydrates
Out of all the energy sources for the human body, researchers have found that carbohydrates are the main source of energy in the human diet. This means that carbs aren’t just for athletes. Carbs are a great source of energy for anyone’s daily activities, including exercise.
You can think of carbohydrates as a source of fuel for the body, otherwise known as calories. As we’ve previously learned, there are two types of carbohydrates: simple carbs and complex carbs. Simple carbs are a quick, sporadic source of energy, while complex carbs are a good source of steady energy.
If you’ve ever heard of an athlete eat candy before a game or training session, that’s because simple carbs, like white sugar, are one of the fastest ways to spike energy. However, this energy kick cannot be maintained for long. Complex carbs may not be as readily available for immediate energy as simple carbs are, but they’re more efficient and healthier. Complex carbs provide sustainable energy, which means the energy is constant and there’s no “crash” like with simple carbs.
One of the main reasons why complex carbs sustain energy throughout the day is because they take longer to digest. Simple carbs like fruit are easy for the body to break down and get rapidly digested, so they don’t provide energy for a long period of time. Complex carbs like starches are slow to digest and therefore slowly provide calories, giving you continuous energy for a longer period of time.
Because of their slow-release properties, complex carbs should be the largest component of daily energy intake.
Isn’t Protein More Important Than Carbs for Building Muscle?
When you think of building muscle, you may think of a high-protein diet. Protein is extremely important in building muscle because the amino acids (the building blocks of protein) help repair and maintain muscle tissue. Essentially, protein helps you recover from workouts because muscles slightly tear during exercise.
If protein is so important, why put an emphasis on carbs? Well, complex carbohydrates don’t get enough credit when it comes to the important roles they play in muscle gains.
Some of the ways that complex carbs help to build muscle include:
1. Carbs help regulate muscle glycogen repletion
You may have heard of glycogen stores before. Glycogen is a form of glucose that is stored for later use. When the body needs energy, glycogen kicks into gear and acts as a ready fuel source.
Carbohydrates and glycogen go hand in hand because carbs are stored as glycogen.
When carbs are low, glycogen stores are low. When carbs are consumed, glycogen stores are full.
Since glycogen is used for energy, it’s important to replenish those stores. This is why researchers recommend to consume carbohydrates immediately following exercise; it replenishes glycogen stores for future use.
2. Carbs prevent muscle degradation
One concern about low-carb diets is muscle loss.
A Netherlands study compared a low-carb diet to other diets and found that restricting carbs results in protein loss. This is because restricting carbs causes an increase in the amount of nitrogen that get excreted by the body. Nitrogen is a component of amino acids (the stuff that forms muscle proteins), therefore nitrogen loss indicates that the muscles are breaking down.
3. Carbs help muscles recover from exercise
The role that carbs play in recovery goes back to glycogen stores. Immediately after exercise, athletes need to replenish their glycogen stores in order to prevent glycogen depletion.
Glycogen depletion, when glycogen stores have run out, causes gluconeogenesis. This is when the body forms glucose from new sources to compensate for the lack of glucose from carbohydrates. When this happens, the body turns to sources like fat and protein to fill this need. Protein acts as the last line of defense when energy is required, meaning that energy accessibility is running very low.
When the body breaks down protein to make more glucose, it takes from the muscle, causing them to waste away.
Gluconeogenesis is more common in carbohydrate-free diets, so be sure to consume healthy carbs to prevent this.
Replenishing glycogen stores with complex carbs is important to prevent protein breakdown and muscle wasting.
Why Athletes Consume a Lot of Carbs
There are many reasons why athletes don’t adopt low-carb or carb-free diets. They know those good carbs are a necessary nutrient to help them power through training sessions, resulting in muscle maintenance and growth.
Some of the reasons why athletes consume a fair amount of carbs include:
1. Carbs prevent muscle weakness
By now, you understand the importance of glycogen stores. Some glycogen is even stored in our muscles.
When you use those muscles during exercise, you tap into the glycogen stores in that particular muscle. When you lift weights with your arms, for example, you’re accessing the glycogen in your biceps.
Some athletes take advantage of glycogen by loading up on carbohydrates (by consuming carbs a day or more before a workout) to maximize the muscle glycogen stores. This can delay fatigue and even improve athletic performance, making for a better workout and stronger muscles.
2. Carbs improve athletic performance
Out of the three macronutrients, carbs are the most efficiently metabolized.
The Academy of Nutrition and Dietetics, the Dietitians of Canada, and the American College of Sports all share the position that high carbohydrate availability is associated with improving performance during high-intensity exercise.
Why? Because carbohydrates are the only macronutrient that can be broken down quickly enough to provide sustained energy during high-intensity training.
Both carbohydrates and protein will both provide 4 calories per gram. But it is much easier for your body to digest and use the calories from a gram of carbohydrate than it is a gram of protein.
Research has shown the link between nutrition and athletic performance is greater than initially believed.
3. Carbs repair muscles
During exercise, muscles slightly tear. Muscles feel sore after intense exercise because of this minor damage that allowed the muscles to exert more force than during regular activity.
After exercise or during rest, the muscles need to be repaired and rebuilt. Just like for building muscle, protein and glycogen is needed for that muscle repair.
The importance of glycogen for muscles can’t be over-emphasized, and in order to maintain glycogen stores, carbohydrates are needed.
What Happens to Muscle When Carbs are Low
With the popularity of low-carb diets, it’s important to discuss the major concern that muscle mass is at risk of deterioration when carbs are low.
Now that we know how important carbs are to build muscle, let’s discuss some of the possibilities when carbs are restricted.
Muscle is Broken Down For Fuel
The body looks to complex carbs as its main energy source. When carbs aren’t available, the body breaks down protein, i.e muscle, for fuel.
Carbohydrates are stored as glycogen, which is a readily available source of energy for when it’s needed. Dietary protein, however, isn’t really meant to be stored in the body specifically as an energy source.
When the body breaks down muscle tissue for energy, it does so to access the amino acids (the building blocks of protein). The amino acids are then broken down into glucose and used for energy.
Carbs help to prevent this process encouraging protein sparing, which means they conserve muscle tissue by providing energy instead. When carbs are present, the body will use carbs first and foremost for energy. When carbs aren’t available, muscle gains that you have worked so hard to achieve can be lost.
Replenishing glycogen stores by consuming complex carbs prevents this muscle loss.
Decreased Athletic Performance
Decreased energy due to low-carb consumption may affect athletic performance. When glycogen stores are low, athletic performance is decreased.
Muscle strength can be compromised and fatigue increases when glycogen stores are low.
It’s widely accepted that athletic performance is somewhat dependent on carbohydrate consumption. Therefore, consuming carbs before the workout for energy and after to replenish glycogen stores are important contributors to improved exercise performance.
Complex Carbs for Muscle Gains
Everyone knows that protein is important for building muscle, but without carbs, the gains just aren’t the same. Complex carbs are vital for sustained energy, athletic performance, and overall muscle building.
However, the type of carbs and when they’re consumed are also vital to experience these benefits.
When to Consume Complex Carbs for Muscle Building
The time of carb consumption also impacts athletic performance and muscle building.
It’s important to consume complex carbs before an intense workout so that glycogen stores are full enough to fuel the training. Consuming complex carbs immediately before a workout could lead to digestive distress, so try to limit complex carb consumption to up to a few hours before an intense workout. If you’re short for energy before an event, lean towards simple carbs.
After exercise, it’s important to consume complex carbs to replenish those glycogen stores for later use.
Balancing Carb Consumption
The amount of complex carbs you eat depends on your body composition goals. Generally, very low carb consumption (<5%) is used for weight loss, while adequate carb consumption (55-60%) is used for muscle gain.
Athletes may pile on the carbs as they are required to train day-in and day-out. So it makes sense that they should consume a higher carb diet than the average person because they have higher energy needs. For non-athletes, it’s generally suggested to adopt a more balanced diet. Even if you’re mostly sedentary, you should still consume some carbs to fuel your daily activities.
If the goal is to build muscle, we now know to eat all three macronutrients, including a fair amount of carbs.
Carbohydrates are the primary energy source for humans. The body uses this nutrient for energy and stores them as glycogen for later use.Athletes rely on carbs for sustained energy, preventing fatigue, and enhancing athletic performance.Carbs are important for muscle building because they’re protein sparing, which means the body looks to glycogen for energy instead of breaking down muscle tissue for energy.Consuming carbs post-workout can prevent muscle loss and help repair muscles.
The moral of this story is that carbs, just like every other macronutrient, have a place in improving your body composition. In the end, it takes a well-rounded diet and a smart routine to build muscle.
Lacey Bourassa is a health and wellness writer in Southern California. Her areas of expertise include weight loss, nutrition, and skin health. She attributes her passion for healthy living to her plant-based diet. You can find out more about Lacey at WrittenByLacey.com.