Illustration of a skinny person building muscle.

How Many Calories Does It Take To Build a Pound of Muscle?

A pound of muscle contains about 1,200 calories of stored energy (study, study). However, just like a mason spends energy laying stones, it also takes energy to construct that muscle, increasing the energy costs by another 500–1,000 calories. And so, overall, it takes about 2,000 calories to build a pound of muscle (study).

A mason can only lay so many stones in a day. Giving him more energy than he can use won’t help him lay those stones any faster. Instead, the extra calories will simply be saved for later. They’ll be stored as body fat. That begs the question: how many calories does it take to maximize your rate of muscle growth?

To answer that question, we have to consider the hardgainer issue. Some people have more aggressive metabolisms than others. It might take 2,000 calories to build a pound of muscle on average, but it varies from about 1,500 to 2,500 calories, depending on the person. We’ll delve into that, too.

A skinny guy building muscle. Illustrated by Shane Duquette for Outlift.

Estimating the Energy Cost of Building Muscle

Muscle is made of water (75%), protein (20%), and a mix of fat and glycogen (5%). Water weighs a lot, but it doesn’t contain any calories. Only the protein, fat, and glycogen can be broken down into energy. That’s why a pound of muscle only contains 1,200 calories, whereas a pound of fat contains 3,500 calories.

This is where people often make a mistake. They assume that since a pound of muscle contains 1,200 calories, it must take 1,200 calories to gain that pound. That’s not quite right. If you’re stimulating muscle growth by lifting weights, you’ll burn around 300 calories for every hour you spend lifting. Then you need to digest all the extra food, burning up even more calories. Once you’ve digested that food, some of the energy is used to fuel muscle-protein synthesis (study, study, study). In the end, it can take anywhere from 1,500 to 2,500 calories to build a pound of muscle.

Once you’ve built that pound of muscle, you also need to maintain it and carry it around. This burns another 12 or so calories per day. As you get deeper into a bulk, those extra pounds of muscle add up. By the time you’ve gained 20 pounds, that’s another 240 calories you’re burning every day. To keep building muscle, you’ll need to factor that in.

Hardgainers & the Role of Genetics

Different people have different metabolic rates. Much of this is explained by how much you weigh and how much you move, but genetics also plays into it (study, study, study, study). There are outliers on either side. That’s why some people can build a pound of muscle with as few as 1,500 calories, whereas others need closer to 2,500 calories.

I wrote a full article about hardgainers on Bony to Beastly. We have another article about variations in metabolism. Some people skinny people really do have much faster metabolisms.

Illustration of a thin hardgainer holding a giant bowl of food, struggling to eat in a calorie surplus.

How Many Extra Calories Should You Eat?

Now we get to the important part: how many extra calories should you eat to maximize your rate of muscle growth? There are a few different paths you could take:

  • If you want body recomposition, building muscle while losing fat, you don’t need a calorie surplus. You can build muscle by getting energy from the fat you burn. This works best for overweight and skinny-fat people.
  • If you want to do a classic bulk, building muscle quickly and leanly, start with a calorie surplus of around 400–500 calories per day. That will have you gaining around 0.5–1 pound per week. This works well for the average person trying to build muscle (article, study).
  • If you want to do a lean bulk, keeping your gains as lean as possible, start with a calorie surplus of around 200–300 extra calories per day. That will have you gaining around 0.25–0.5 pounds per week. This works best for people who gain fat easily.
  • If you want to do an aggressive bulk, maximizing your rate of muscle growth, start with a calorie surplus of around 500–1,000 calories per day. This works best for skinny beginners.

If you’re curious about how many calories you’ll need to eat overall, here’s a calorie calculator. There’s a dropdown menu that lets you choose your path. You can track your calories if you want, but you don’t need to. All you need to do is add extra calories to your diet. You do that by having more snacks or eating larger servings.

The real trick is to weigh yourself every week, see how much weight you’ve gained, and then adjust your calorie intake accordingly. If you want to gain weight faster, add another 200 calories. If you want to slow things down, eat 100 fewer calories. Keep weighing yourself and adjusting.

Illustration showing the Bony to Beastly Bulking Program

Alright, that’s it for now. If you want more muscle-building information, we have a free muscle-building newsletter. If you want a full exercise, diet, and lifestyle program to help you build muscle and improve your health, check out our Bony to Beastly Program (for guys) or Bony to Bombshell Program (for women). Or, if you’re already an intermediate lifter, check out our Outlift Hypertrophy Program.

Shane Duquette is the co-founder of Outlift, Bony to Beastly, and Bony to Bombshell. He's a certified conditioning coach with a degree in design from York University in Toronto, Canada. He's personally gained 70 pounds and has over a decade of experience helping over 10,000 skinny people bulk up.

Marco Walker-Ng is the co-founder and strength coach of Outlift, Bony to Beastly, and Bony to Bombshell, and is a certified trainer (PTS) with a Bachelor's degree in Health Sciences (BHSc) from the University of Ottawa. His specialty is helping people build muscle to improve their strength and general health, with clients including college, professional, and Olympic athletes.

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  1. Derrick on June 1, 2023 at 6:22 am

    My biggest problem is that I don’t even know if I should be gaining weight or not. I’m a lean 44 year old dude with a little extra fat on the abs -nothing bad- who has recently fallen in love with calisthenics. I weigh 165 and wouldn’t mind some more definition, but don’t necessarily want to get big. No clue what to do.

    • Shane Duquette on June 1, 2023 at 8:19 am

      Super cool art, Derrick!

      If you want to get better at calisthenics, it can help to build muscle, especially in your upper body and core. If you’re already reasonably lean, it will be hard to build a significant amount of muscle without gaining weight. The extra weight you gain will make you heavier, but if it’s mostly muscle, it will wind up being a positive overall.

      You don’t need to worry about getting too big. It won’t sneak up on you. If at any point you feel like you’ve gotten too muscular, you can just stop gaining weight. That rarely happens, though. Most natural lifters like how they look as they get stronger.

      The fastest path to more muscle definition is by burning fat, but I’d do that later. Build some muscle and then settle back down to a lower body-fat percentage afterwards. That works much better than doing it the other way around.

      This is all totally up to you, though 🙂

      • Dan on July 10, 2023 at 9:31 am

        I’m greatly enjoying the Outlift program, and all the research based information. Could you suggest a vegetarian cookbook for lean bulking? Preferably without tofu or soy. I’m fine with dairy products and fish. I’m 56 and trying to reduce my mammal consumption. Thanks for all the great info!

        • Shane Duquette on July 10, 2023 at 10:45 am

          Hey, Dan. That’s awesome! Glad you’re liking it.

          I don’t know of any vegetarian recipe books that are specifically for lean bulking, but I recently bought At Home in the Whole Food Kitchen. It’s a vegetarian cookbook with a ton of great recipes in it. I especially like the red lentil stew recipe.

          Outside of that recipe book, I’m a big fan of lentil stew in general. I also eat a ton of trail mix made from dried fruits, peanuts, soybeans, and pumpkin seeds. And I snack on apple slices dipped in peanut butter. Tons of great vegetarian bulking meals.

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