Does Muscle Burn Fat?

At the very heart of the question, "does muscle burn fat?" is your metabolism. You metabolism is simply just the process by which your body uses calories.

In my opinion, one of the most misunderstood things about weight loss is the role that muscle plays in burning fat.

When you think about it, though, it’s not surprising.

The easiest way to measure success is on the scale. Measuring body fat percentage is hard (though I will give you a way to make it easier).

Turns out body composition determines not only the way your body looks (you have to get body fat percentage pretty low to see your abs), but also more important for health that weight alone.

This leads me to today’s question

Hey Tim, this is an interesting question. And it has an interesting answer. It might just change your perspective on rapid weight loss forever...

Now, clearly, to melt pounds, you have to have a calorie deficit.

So, without thinking about it, answer this question: how would you create a calorie deficit?

If you are like most people out there, you gave one or both of these answers: diet and exercise.

Simple, right? Cool.

Now, to answer “does muscle burn fat,” let's focus on exercise. Of all the calories you burn each day, what percentage do you think comes from your workout?

Would you believe only about 30%? Yep, that's right. Not even half of the calories you burn each day come from exercise.

If only 30% of the calories you use everyday are used through exercise, how do you burn the other 70%.

Basal Metabolic Rate, or BMR

It's through a process called your Basal Metabolic Rate, or BMR. You BMR is the number of calories your body uses to keep itself functioning.

If you are like the vast majority of folks out there trying to burn fat permanently, you are ignoring your BMR, and, as a result, 70% of your opportunity to burn calories.

That's crazy!

Think of it this way...

Let's say you burn 2000 calories per day. Following the 30% to 70% distribution, you burn 600 calories from exercise and 1400 through your BMR.

Now, what if I told you that you can increase calories burned by 5% either through exercise or through BMR. Which would you choose?

Clearly, you would choose BMR. (a 5% increase in exercise is 30 calories, and a 5% increase in BMR is 100 calories).

Do you see how important BMR is now?

You see, one of the main drivers of your BMR is your lean body mass. A large part of your lean body mass are your muscles.

So, Seriously. Does Muscle Burn Fat?

I laid that foundation so that we can attack the question, "Does muscle burn fat?" head on.

Here we go.

The formula for determining your BMR is called the Katch-McArdle formula. It is:

BMR = 370 + (9.79759519 X Lean Mass in pounds)

Yeah, it looks intimidating. But I assure you that it’s not. What it really says is this…

For every pound of muscle you have, you burn about 10 calories.

So does muscle burn fat? Not directly. But it definitely burns calories.

Here’s how that works…

Go back to our example of the person that burns 2000 calories per day. We said in our example that they burn about 1400 calories through their BMR.

Now let’s say they go on a crash diet and lose 6 pounds in the first week… 3 pounds of fat and 3 pounds of muscle. That is, you body composition (body fat percentage) doesn’t change.

At the end of week 1, their BMR would be 1370 (approximately). They would have to add 5% more exercise to burn the same 2000 calories the following week, or reduce their calorie intake by another 30 calories per day. And that’s just after 1 week.

Now, let’s say that instead of that rapid weight loss, you lost 2 pounds, all from fat. Your BMR doesn’t change at all. This is because your lean body mass doesn’t change.

We can carry this out to its logical conclusion. As long as you burn mostly fat (by losing total weight at a slower pace), you minimize the effect on your metabolism, AND lower your body fat percentage so that you look better as well.

This is why most experts recommend a weight loss of no more than 1% or so of your total body weight per week. Any more than that, and you start to shed muscle.

Because muscle does burn fat indirectly, it is important to keep track of how much muscle and fat you lose when you are losing weight.

Estimating Body Fat Percentage

Now that’s all very cool stuff, but...

We all know it’s easier to step on a scale and gauge your weight than it is to measure body fat percentage. That is, unless, you have an easy way to estimate body fat percentage...

Here are two great resources. One is a calculator that uses some simple measurements to give a fairly accurate estimate of body fat percentage. The other is the same method used by the US Army to estimate the body composition of its soldiers.

Body Fat Calculator

Army Body Fat Worksheet

Does muscle burn fat? No. But it certainly makes burning fat easier!

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