Today, I’d like to answer the question, “Why Does Muscle Burn More Calories Than Fat?”
It occurred to me that I have often mentioned on this very website that building lean muscle is one of the most important factors when it comes to burning body fat (and of course calories).
However, I’ve kind of just left it there – no real explanation.
I think I’ve been more far more focused on explaining that “lean muscle” doesn’t mean big and bulky, as many people assume it to be.
I’ve typically explained that lean muscle is what gives you that sleek, sexy, and athletic look that most people crave.
Well done to me.
A big pat on the back.
Well, actually NO.
It’s all well-and-good me saying it, but I’m sure you’d much rather know why muscle burns more calories than fat.
Additionally, many of the claims you hear about the number of calories than lean muscle burns are hugely exaggerated.
So, I’ll cover that too.
Why Does Muscle Burn More Calories Than Fat?
The Main Reason Muscle Burns More Calories Than Fat
Resting energy expenditure is the main reason that muscle burns more calories than fat.
Your resting energy expenditure or resting metabolic rate is basically the number of calories your body burns while you’re at rest.
The reason for this is that muscle tissue is more metabolically active than fat tissue.
Muscle cells will typically be broken down by exercise and will therefore need to repair and rebuild themselves.
This process will involve burning more calories.
Therefore, the more muscle you have the higher you can expect your resting energy expenditure to be.
I’ve written many times previously about resting energy expenditure, and also provided online calculators.
If you want to know exactly how many calories you burn while at rest then check out my article, “How Many Calories Does the Average Person Burn in a Day?”
Why Does Muscle Burn More Calories Than Fat? – Protein Synthesis
Another important factor in the difference between calories burned by muscle and fat is protein synthesis.
This comes down to how either muscle or fat tissue is maintained.
Muscles have far more dynamic tissues.
Yet another reason that muscle is more metabolically active than fat.
This means that in order to maintain muscle tissue there needs to be proteins digested, as well as proteins which are synthesized.
The process of both protein digestion and synthesis burns calories.
However, fat tissue doesn’t require anywhere near as much calorie expenditure from the body, as it is stored at rest.
In the simplest of terms, the body has to work much harder to maintain muscle tissue than fat tissue.
The harder the body works, the more calories it will burn.
Lean Body Mass vs. Lean Muscle Mass
The term lean muscles actually originates from lean body mass.
However, it’s important not to confuse the two.
Lean body mass is often referred to as “lean mass” and is basically the total weight of your body minus the fat mass.
Therefore, lean body mass is composed of your bones, muscles, organs, skin, and water in the body (minus the fat mass of course).
A healthy lean body mass is considered to be around 70-90%.
So, fat mass will be in the 10-30% range.
Although, what is healthy differs between men and women.
Women can be considered “healthy” with a lower percentage of lean body mass and a higher fat mass percentage.
Men will generally have a higher percentage of lean body mass and a lower body fat percentage.
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On the other hand, lean muscle mass or simply “muscle mass” is the amount of skeletal muscle that the body is composed of.
For the average male this is approximately 42% of your overall body weight.
And for the average female the figure is approximately 35%
The Best Way to Increase Lean Muscle Mass
I think every single one of you reading already knows the answer to this one.
Resistance training is the best way to increase lean muscle mass (so that you can burn more calories while at rest).
Resistance training is most commonly associated with lifting weights, but in truth it simply means making your muscles work against a weight or force.
The following exercise formats could all be considered resistance training:
- Free Weights
- Weight Machines
- Medicine Balls
- Suspension Equipment
- Resistance Bands
- Your Own Body Weight
There are many more items I could add to this list, but these are the basic types of resistance training.
As mentioned, we typically associate resistance training with free weights such as barbells and dumbbells.
Plus we can also add kettlebells into the category of “free weights”.
Equipment such as sandbags and medicine balls also ensure that the muscles need to work against weight.
Weight machines are typically seen as a beginner’s route into lifting weights.
Weight machines are fixed in place and therefore the weight must move in a specific direction.
Whereas, free weights can be moved in a variety of directions, which usually means that many more stabilizing muscles are at work.
Suspension equipment, such as the TRX System (Total Resistance Exercise) is another form of resistance training.
This will utilise both your body weight and the forces of gravity in order to perform an exercise.
Plus, we can’t forget that using your own body weight is also a form of resistance training.
Try telling me that a push up or pull up doesn’t involve working against a weight or external force.
So, if you want to build lean muscle mass, you will need to perform any (or all if you wish to) of the above training protocols.
Just as a side note, I’m guessing you’ve asked, “why does muscle burn more calories than fat?” because you’re interested in calorie expenditure.
This is why I think a mix of aerobic training, or what we typically call “cardio” and resistance training is the best way forward.
Aerobic training will definitely burn more calories than resistance training during your actual workout.
However, as we now know, resistance training increases lean muscle mass, thus ensuring you burn more calories throughout the day.
Calories Burned By Muscle and Fat
Firstly, I will say that muscle burns almost 3 times as many calories as fat per kilogram of body weight.
When you say it like that it sounds impressive, right?
In fact, the figures show that muscle burns approximately 13 calories per kilogram of muscle tissue per day.
Fat burns approximately 5 calories per kilogram of fat tissue per day.
For those of you who like to work in pounds:
- 1 pound of muscle will burn 5.9 calories per pound of muscle tissue per day.
- 1 pound of fat will burn 2.3 calories per pound of fat tissue per day.
As I say, initially this does sound very impressive, and I’m sure you’re all ready to “hit the weights” and try adding as much lean muscle to your frame as possible.
Adding Lean Muscle is Harder Than You Think
However, I will say that adding just one kilogram of lean muscle to your frame is actually far harder than you would think.
I’m sure we’ve all seen magazine articles or workout programs that claim that you can add 10kg of lean muscle (22lbs) in a month.
But, in truth, these are hugely exaggerated claims.
How much lean muscle you can add will depend on many factors, especially the type of training that you’re doing, as well as genetics.
I would say that a complete beginner to resistance training will probably not add much more than 1kg of lean muscle a month.
Someone with more experience of training could possibly double this figure to 2kg.
Of course, if you were to focus on just the big barbell exercises, you train regularly, and your nutrition was on-point, you may even push this figure up to 5kg of lean muscle being added over the course of a month.
However, while this all sounds fantastic, taking into consideration the above three scenarios would mean that you would only burn an additional 13, 26, and 65 calories a day respectively.
Just for a little perspective, an oreo cookie is approximately 53 calories.
Does Muscle Weigh More Than Fat?
Let’s Look at Some Calorie Calculations
I’ve previously written a number of articles which included calorie calculations based on the “average person”.
So, I’m going to do the same today to show how many calories muscle and fat are actually burning per day.
Our “average person” is male, 39 years old, 5ft 9in tall, and weighs 77kg (approximately 170lbs if that’s your preference).
Using this online tool, that is included with various other tools in the article I have mentioned above, we can see that this person burns approximately 1,740 calories per day while at rest.
Sticking with the “average”, this man’s lean muscle mass is 42% and his fat mass is 20%.
This would mean that 32.34kg of his overall weight is skeletal muscle and 15.4kg is fat
Therefore, his lean muscle is burning 420.42 calories (32.34 x 13) per day.
And his fat mass is burning 77 calories (15.4 x 5) per day.
So, when we take into consideration all the “averages”, i.e. height, weight, age, percentage of muscle mass, percentage of body fat, etc. we can see that this person’s overall muscle mass is burning over 5 times as many calories as their overall fat mass.
Calories Burned in The Grand Scheme of Things
The figures above tell us that approximately 25% of daily calories burned comes from muscle.
Whereas, 4.4% of calories burned comes from fat.
So, in reality, there really is no contest.
The vast majority of us have more lean muscle than fat in the body.
In fact, you would need to be considered morbidly obese for this not to be true.
We now know that the body has to work harder to feed and maintain muscle than it does fat, and this process burns calories.
However, in the grand scheme of things both muscle and fat are at low-end of calorie expenditure from the perspective of resting tissue.
The Body’s Major Organs
Your major organs, such as the brain, heart, liver, lungs, and kidney tissues, actually burn far more calories because they are constantly working to ensure that the body keeps ticking over.
The brain actually burns 200 calories per kilogram per day.
The average male human brain weighs 1.37kg and the average female brain weighs 1.2kg (I’m saying nothing!)
So, in effect, going back to our average person above, their brain is burning 274 calories a day.
The other major organs I’ve mentioned above equate to approximately a further 3kg, so these alone and their daily functions will easily equate to 50% of the calories we burn on a daily basis.
Therefore, in the grand scheme of things, lean muscle and fat tissue don’t have as much of an effect on the body’s calorie-burning capabilities as we may think.
With that said, we should all still be resistance training and adding lean muscle to our frame.
It helps to increase your strength, keeps you fit and healthy, reduces the risk of injury, plus it makes you look great.
So, in summary, the reason that muscle burns more calories than fat is that it is more metabolically active in the body.
Plus it takes more energy (calorie expenditure) to maintain muscle than fat.
However, when we take all the body’s organs and their functions into consideration, there is far more calorie burning going on elsewhere.
With that said, maintaining or adding lean muscle tissue will still obviously burn far more calories than fat, and it is much healthier for you as well.
I mentioned earlier that in order to literally turn your body into a calorie-burning machine I would always favour a mix of resistance training and cardio.
One of my favourite workout programs to achieve this is Bodyweight Burn.
The workouts have a three-pronged attack to torching calories, burning body fat, and building lean muscle.
Plus the workouts only take 21 minutes to complete and require absolutely no equipment whatsoever.
To discover more please check out my Bodyweight Burn Review.
Hi, I’m Partha, the founder of My Bodyweight Exercises. I’m someone who’s been passionate about exercise and nutrition for more years than I care to remember. I’ve studied, researched, and honed my skills for a number of decades now. So, I’ve created this website to hopefully share my knowledge with you. Whether your goal is to lose weight, burn fat, get fitter, or build muscle and strength, I’ve got you covered.