Some say that for every pound of muscle you gain, your body will burn an extra 50-100 calories per day.
According to Adam Zickerman, author of Power of 10: The Once-a-Week Slow Motion Fitness Revolution, “three extra pounds of lean muscle burns about 10,000 extra calories a month.”
Zickerman also says that three extra pounds of muscle “burns as many calories as running 25 miles a week, or doing 25 aerobic workouts a month without leaving your couch.”
You’ve probably read similar claims that muscle “burns calories around the clock just to maintain itself, even while you are sleeping or sitting at a desk.”
Here’s the truth:
When you gain muscle, your resting metabolic rate (the number of calories your body burns at rest) does go up. But this increase is a lot less than the 50-100 calorie figure you’ll often see written.
Where does the 50-100 calorie figure actually come from?
I have no idea. It just seems to be one of those myths that have been around for so long that its accuracy is no longer questioned, and probably exists for the same reason we have misconceptions about a lot of things.
Somebody says something, somebody repeats it, and then we repeat it. Suddenly it’s established as fact.
So, how many calories does a pound of muscle burn… really?
At Rest, One Pound of Muscle Burns 5-6 Calories Per Day
Most research shows that muscle doesn’t burn that many calories when it’s in a resting state. And the energy cost of maintaining muscle tissue pales in comparison to other parts of the body.
In fact, the heart and kidneys have the highest resting energy requirements (200 calories per pound). The brain (109 calories per pound) and liver (91 calories per pound) also have high values.
In contrast, the resting metabolic rate of skeletal muscle mass clocks in at just 6 calories per pound, while one pound of fat burns just 2 calories .
|Organ/tissue||Daily metabolic rate|
|Fat||2 calories per lb|
|Muscle||6 calories per lb|
|Liver||91 calories per lb|
|Brain||109 calories per lb|
|Heart||200 calories per lb|
|Kidneys||200 calories per lb|
As is often the case with these things, not everyone agrees on the exact figure.
Writing in the American Journal of Clinical Nutrition, Robert Wolfe, Ph.D., Chief of Metabolism and Professor of Biochemistry at the University of Texas Medical Branch, points out that, “every 10-kilogram difference in lean mass translates to a difference in energy expenditure of approximately 100 calories per day, assuming a constant rate of protein turnover.”
That’s 10 calories per kilogram of muscle, which works out at a little less than 5 calories per pound.
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In other words, while skeletal muscle and body fat are the two largest components, their contribution to resting energy expenditure is smaller than that of organs.
The vast majority of the resting energy expenditure of your body comes from organs such as liver, kidneys, heart, and brain, which account for only 5% to 6% of your weight.
Although bone has traditionally been viewed as a relatively static tissue, it’s also metabolically active.
Some even consider bone an endocrine organ because of its capacity to secrete a hormone called osteocalcin, which plays a role in glucose and fat metabolism .
Resting Muscle vs Recovering Muscle
I do want to make an important distinction between resting muscle and recovering muscle.
The estimates of the energy cost of muscle I’ve just given do make one assumption — a constant rate of protein turnover .
However, most types of resistance exercise will accelerate protein turnover (an increase in the rate of protein synthesis and breakdown), which is going to increase calorie expenditure in the hours (and, in some cases, days) after exercise.
And there are studies to show that the more muscle you have, the more calories you’ll burn after an intense workout .
When exercise ends, it takes time for everything to get back to normal. Depleted glucose and fat stores need to be refilled. Damaged muscle cells need to be repaired. All of this requires energy.
And the more rebuilding that has to be done, the more calories are being burned after your workout is over. Or to put it another way, recovering muscle has a much greater energy requirement than resting muscle.
Muscle Boosts Your Metabolism… But Not by Much
So, what does all of this mean for you?
If you were to lose two pounds of body fat and replace it with two pounds of muscle, your resting metabolism will increase by less than 10 calories per day.
It would take a vast amount of muscle to substantially increase your resting energy expenditure — far more than most people are going to build in the gym.
Which brings me to another important point.
Unless they’re very overfat, returning to exercise after a layoff, or just starting an exercise program, very few people gain a lot of muscle and lose a lot of body fat at the same time.
Your body just isn’t that great at doing both things at once.
That’s why I recommend you focus on one of two goals when you’re trying to get in shape — building muscle while minimizing fat gain, or, losing fat while preserving lean muscle mass.
Resistance Training and Weight Loss
None of this means that training with weights is pointless if you want to lose fat.
Far from it.
In fact, lifting weights will improve your body composition in a number of different ways.
Firstly, strength training burns calories (and fat). Not just during your workout, but – provided you train hard enough – after it’s finished as well.
Second, if you don’t do some kind of resistance exercise while you’re dieting, a lot of the weight you lose will come from muscle as well as fat.
If you are fortunate enough to gain a significant amount of muscle while you’re losing body fat, the impact of the extra muscle on your resting metabolism will be small, and certainly won’t amount to 10,000 extra calories a month.
Does Fat Turn Into Muscle?
There’s a good chance you’ve heard that once a fit person stops training, all their muscle will turn into fat.
I’ve even heard some people use this excuse to explain why they do no exercise.
“There’s no point working out,” they complain. “As soon as I stop, all that muscle will turn into fat.”
Muscle cannot turn into fat. Fat cannot turn into muscle. They are two completely different substances.
Muscle tissue can increase or decrease in size.
Fat can be lost or gained.
But you can no more turn fat into muscle than the alchemists of the past could turn base metals into gold.
However, what you can do is use the energy in stored fat to fuel the process of muscle growth.
What exactly do I mean by that?
First, doing the work required to stimulate muscle growth requires energy.
Go to the gym and lift weights for 45-60 minutes. Depending on how much weight you’re lifting and how hard you train, you’ll burn several hundred calories just moving the weights from point A to point B.
Much of the energy required to fuel that workout will come from carbohydrate. However, the workout itself will set in motion a series of metabolically costly processes that can last several days.
And the largest reservoir of chemical energy stored in your body is fat, which can be used to supply the energy required for the repair and remodeling process that takes place in the hours and days after training.
In fact, there are many studies, which I talk more about here, where both fat loss and muscle gain happen concurrently.
They didn’t turn fat into muscle.
A fat cell is a fat cell, a muscle cell is a muscle cell, and you can’t turn one into the other.
But they did use the energy supplied by fat to synthesize new muscle tissue.
In short, you can’t turn fat directly into muscle.
But the energy stored in fat can and will be used to fuel muscle growth.
As long as you’re in a calorie deficit (which means your calorie intake is less than daily energy expenditure), eating enough protein and lifting weights 2-4 days a week, you will be able to lose fat and replace some of it with muscle.
This will create the illusion that you’ve figured out how to turn fat into muscle, and everyone will think you’re a miracle worker.
The only caveat is that your body becomes less likely to use stored fat to fuel muscle growth the less of it you have.
So, while fat loss and muscle growth occur simultaneously, it’s a phenomenon that’s generally limited to people who have a lot of fat to lose, and are relative newbies to lifting weights.
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