Do I Need Carbs to Build Muscle? (According to Science)

Do you need carbs to build muscle? Yes or no?

Yes, potentially. No, it depends.

From my experience over the years, both with myself and with my clients, it comes down to how you personally feel during your training. What's important is how you're feeling going into your training, and how you're recovering after your training—that's what matters, and carbs play a big part.

Do I Need Carbs to Build Muscle?

Technically, we don't need carbs to build muscle. Carbohydrates are actually not an essential nutrient. But that doesn't mean that they can't be beneficial when it comes to optimizing muscle growth.

Building muscle is going to be a result of making sure that you're staying on top of your resistance training program. It also includes eating enough protein, and making sure that you're eating enough calories in general to fuel that muscle growth. Those are going to be the big players.

Carbohydrates Play an Important Role in Performance

Carbs can play a role in improving performance and also optimizing recovery afterward. If we just think about it, practically, carbs can give you energy. If you're going into your training, feeling good and you get that from maybe having a carbohydrate-rich meal beforehand or snack, then you're going to train harder—and build more muscle over time. Carbs can be beneficial in that regard, and they can also be super beneficial post-workout (when we're thinking about recovery).

Don't Forget About Recovery

This is the part that a lot of people tend to forget about when it comes to muscle growth—you actually have to recover from the workout that you're doing in order to grow muscle. When you're training and breaking your muscles down in the gym, you're not actually building muscle yet. The muscle is built when you're recovering: sleeping, fueling, and resting.

Carbs Build Muscle in the Post-Workout, Too

Carbs can play a role in post-workout nutrition, as well. They can help you post-workout get you into more of that parasympathetic state. The parasympathetic state is within our nervous system—we have our sympathetic state and our parasympathetic state.

Our sympathetic state is what we're in when we're working out—that's the workout high (adrenaline, high energy, flight or fight mode). Our parasympathetic state is our rest and digest mode. Post workout, we want to get out of that sympathetic mode and into that parasympathetic mode—that rest and digest mode. This helps kickstart recovery, and carbs can help do that.

How Do Carbs Help With Muscle Building and Recovery?

One of the main mechanisms behind that is that carbs actually spike insulin. When you spike insulin, you decrease cortisol because these are two opposing hormones.

Spiking insulin can help you bring cortisol down. Cortisol is our overall stress hormone. And it's not that high cortisol levels are bad or anything like that—you actually want to have high cortisol during your workout. That's helping you with energy to stimulate performance. But when you're done with your workout, you don't want that cortisol to stay high.

A benefit to carbohydrates is that when you consume carbohydrates you're going to bump up that insulin level. This decreases cortisol levels and gets you into that parasympathetic rest and digest mode. That's one of the benefits of carbs that a lot of people don't think about.

Refill Glycogen Stores With Carbs

Carbohydrates help to refill your muscle glycogen stores. Muscles glycogen is just the storage form of carbohydrates in your muscle. And that's going to be important for muscle growth and performance over time.

Consuming carbohydrates post workout or anytime throughout your day can help refill those stores so that you're good to go come next workout. Those are just some of the benefits that carbon carbohydrates have in terms of building muscle, but they're not the only ones.

However, I'm not saying that you can't build muscle without consuming carbohydrates—not at all you absolutely can build muscle without eating carbs.

But it's not easy.

If we're talking about optimizing muscle growth and getting the best bang for your buck, you always have to just come back to how you feel. Do carbs give you more energy for your workouts? Do you feel like they help you better enter a rest state after your workouts? If so, then they might be worth it.

I actually did a study looking at the ketogenic diet and CrossFit athletes, and it's found that they can actually increase their performance to the same degree that those consuming carbs could. So you can increase performance. You can build muscle without carbohydrates, but we're talking about optimizing muscle growth, and that's going to come back to the individual and how you personally feel and what works best for you.

Want to learn more about building muscle (with or without carbs)? Check out all the other resources on the website—including our women's fitness program.