Do you need carbs to build muscle? No you don’t.
However, the fact that it’s possible to build muscle on a diet consisting primarily of fat and protein doesn’t necessarily mean it’s a good idea to do so.
Nor does it mean that muscle mass won’t be gained more quickly with a diet that’s relatively high in carbohydrate.
In fact, from a muscle-building point of view at least, most people are better off getting somewhere between 30 and 50 percent of their daily calorie intake from carbohydrates.
Let me explain why.
How Your Muscles Grow
Take a closer look at a slice of muscle tissue, and you’ll see that it’s made up of many smaller muscle fibers.
Your muscles get bigger when these individual fibers become thicker, a process known as hypertrophy.
Over a period of weeks and months, as the individual fibers inside your muscles grow, your muscles become bigger and stronger as a result.
Studies show that the process of muscle growth begins soon after you leave the gym .
In the hours and days that follow, your body is busy repairing damaged muscle fibers, as well as synthesizing the new muscle protein that makes each fiber bigger than it was before .
Why You Don’t Need Carbs to Build Muscle
Is carbohydrate required for that muscular remodeling process to happen? No.
In fact, very low-carbohydrate diets have been shown, in some studies at least, to deliver similar gains in muscle mass as their high-carbohydrate counterparts .
However, while carbohydrates don’t play a critical role in stimulating muscle growth, that doesn’t mean they’re not important.
For the most part, carbohydrate is useful to the degree that it helps to power muscular work during high-intensity exercise.
What exactly do I mean by that?
Most of the carbohydrate you eat ends up as glucose. If your body doesn’t need that glucose for energy, it gets stored, primarily in your muscles and liver. Glucose stored in your muscles and liver is known as glycogen.
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Muscle glycogen is a major source of fuel during high-intensity exercise [3, 4]. When your muscles are full of glycogen, you’re able to do more work in the gym. And the more work your muscles do, up to a point at least, the faster they’ll grow.
Carbohydrate ingestion before and during resistance training also allows for a higher volume of training during longer workouts lasting around 45 minutes or longer .
Even if your muscle glycogen stores are half full, the potential is still there for your performance in the gym to be compromised, especially if you’re following a hypertrophy-style workout routine that involves a relatively high volume of training.
That’s because there’s a difference between the amount of glycogen available in a muscle versus what’s available to an individual muscle fiber.
From Sweat Science columnist Alex Hutchinson:
“If you’ve got 250 mmol/kg out of a maximum capacity of 500 mmol/kg, your muscles are half-full. But that might mean that some fibers are mostly full while others are mostly empty.”
“When you do all-out exercise, you need all your muscle fibers to fire. If some are empty, then your performance will be compromised even if there’s carbohydrate in the fiber next door.”
Put differently, carbohydrate comes in handy because it helps you put in the work that stimulates muscle growth, not because it makes a direct contribution to growth per se.
None of this means you can’t gain muscle on a low-carbohydrate ketogenic diet, because you can. Plenty of people have done it.
But in most cases, the process is going to be a lot faster and easier with a diet that’s higher in carbs.
Bodybuilders, for example, will often restrict their carbohydrate intake in order to get ripped for a contest. But once the contest is over, they’ll typically increase their carbohydrate intake substantially to start gaining muscle again.
If you’ve got some fat to lose, and want to maintain (or even gain) some muscle at the same time, a low-carbohydrate diet is certainly a viable option.
In fact, there are several studies out there to show that ketogenic diets do just as well as their higher carb counterparts when it comes to preserving muscle while you lose fat, which I talk more about here.
However, you don’t have to go full keto to get the benefits of restricting your carb intake.
Many people do just fine with a moderate intake of carbs, cutting out the sugary snacks and replacing some of the starchy carbs with fruit and vegetables. And by moderate, I’m talking about 30 per cent or so of your total daily calorie intake.
Do You Need Post-Workout Carbs to Build Muscle?
You don’t need carbs after a workout to build muscle. While the rapid provision of carbohydrate after exercise is important for some people in certain situations, for most people, it isn’t.
It’s true that muscle glycogen is synthesized more quickly if you take in some carbs immediately after a workout rather than several hours later.
In fact, delaying the consumption of post-workout carbs for just two hours has been shown to slow the rate of muscle glycogen resynthesis by as much as 50% .
This matters if you’re involved in a sport or activity where the length of time between exercise is relatively short.
In this case, speeding up the rate at which glycogen levels are replenished takes on a much greater importance . You want those muscles ready for action again as soon as possible.
However, while the speed of glycogen restoration is important for some people in certain circumstances, for most people it isn’t.
I’m not training twice a day, and you’re probably not either. Most people hit the same muscle group 2-3 times a week, which allows plenty of time for muscle glycogen levels to be topped up before the next workout.
As long as you’re getting enough carbohydrate in your diet, glycogen stores will return to normal after a day or two, regardless of when that carbohydrate is consumed [8,9].
In short, most research shows that the post-workout consumption of protein and carbohydrate has no additional muscle-building benefits compared to protein alone [10, 11].
That is, a post-workout meal could consist of nothing but protein and fat, and you’ll likely see a similar rate of muscle growth had you eaten carbs as well.
In fact, the combination of fat and protein has a number of interesting benefits as far muscle growth is concerned.
In one study, a post-workout drink containing whole milk was found to be more anabolic than fat-free milk . Although both drinks led to an increase in protein balance, it was the high fat whole milk that delivered the greatest results.
In another trial, eating whole eggs did a better job of boosting muscle protein synthesis than eating the egg white, even when protein intake was identical .
Frequently Asked Questions
How much protein should I eat in a day to gain muscle?
Most research suggests that you should be eating at least 0.7 grams of protein per pound of body weight (1.6 grams per kilogram) each day to gain muscle.
To calculate the amount of protein you need for muscle growth, multiply your bodyweight in pounds by 0.7. If you prefer metric, multiply your bodyweight in kilograms by 1.6.
That protein should be distributed across 3-4 smaller meals, rather than one or two big ones.
Studies show that distributing protein intake evenly throughout the day does a better job at increasing muscle protein synthesis than the same amount of protein squeezed into a smaller number of larger meals [14, 15].
Ideally, you’ll eat some protein within the first few hours after getting out of bed, before a workout, after a workout, and before going to bed.
How much carbs should I have a day to build muscle?
For most people, your carbohydrate intake should average somewhere between 30 and 50 percent of your daily calorie intake.
If you’re trying to lose some fat while retaining/gaining muscle mass, your carbohydrate intake will be closer to the lower end of that range.
Anyone whose main goal is to gain weight and build muscle will typically benefit from a diet where around half of the total calories come from carbohydrate.
Expressed relative to your weight, that’s going to mean consuming somewhere 2-5 grams of carbohydrate per kilogram of body weight per day [16, 17].
Will I lose muscle mass if I don’t eat carbs?
When you make the switch from a high to a low-carbohydrate diet, it might appear that muscle mass has been lost in a relatively short period of time.
But that’s mainly because you’ve lost glycogen and water, rather than actual muscle protein.
When you severely restrict the amount of carbohydrate in your diet, the glycogen and fluid content of your muscles is going to drop.
Given the fact that some of the material stored in your muscles has been lost, we could say that you’ve lost muscle, particularly as they may take on a slightly deflated appearance.
All that’s happened is your muscles have flattened out a bit because there’s not as much stuff in there as there was before.
You haven’t lost actual muscle protein. Rather, you’ve just lost some of the substances stored around those proteins, which can be replaced relatively quickly.
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