The case for building muscle to lose fat appears to be a simple one.
For every pound of muscle you gain, your metabolic rate will rise by between 50 and 100 calories per day.
Because of this, gaining just a few pounds of muscle will burn as many calories as running 25 miles a week.
All while you’re sleeping, sitting at your desk or resting on the couch.
Or is it? I’m not so sure…
The first problem is that muscle doesn’t burn 50-100 calories per pound.
You probably know that muscle tissue is more metabolically active than fat, and that it helps you burn more calories during the day.
So, in theory at least, an increase in muscle mass means that more fat will be burned.
Unfortunately that’s only partially correct — and certainly not to the extent we once believed.
In fact, research shows that the resting metabolic rate of muscle is a lot lower than most people think – around 6 calories per pound.
I should also point out that fat is more than just lifeless tissue. It secretes proteins such as leptin and cytokines, which can affect your metabolism. Fat has a metabolic rate of around 2 calories per pound.
So if you were to drop a couple of pounds of fat and replace it with the same amount of muscle, your resting metabolic rate would rise by less than 10 calories per day. That’s not enough to have any kind of meaningful impact on fat loss.
The estimates of the resting metabolic rate of muscle I’ve just given do make one assumption — a constant rate of protein turnover.
However, strength training will accelerate protein turnover (which refers to an increase in the rate of protein synthesis and breakdown) in the hours and days after training.
In other words, while the metabolic rate of muscle at rest isn’t as high as some people think, the metabolic rate of muscle while it’s recovering means that people with more muscle mass are going to burn more calories in the post-exercise period.
The second problem is that you’d need to gain a huge amount of muscle to have a significant impact on your metabolism.
To burn an extra 10,000 calories a month — enough to lose almost 3 pounds of fat – you’d need to gain more than 50 pounds of muscle.
That’s an awful lot of beef. It’s much more than the average person is going to build over the course of their training lifetime.
In short, the idea of building muscle to lose fat is a flawed one.
But that doesn’t mean strength training is pointless if you’re trying to drop fat. Far from it. Lifting weights is going to improve your body composition in a couple of important 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 form of strength training while you’re dieting, a lot of the weight you lose will come from muscle as well as fat.
It’s also worth pointing out that the amount of weight you lose is a lot less important than where that lost weight comes from. If you drop 10 pounds of fat while gaining 3 pounds of muscle, your weight on the scales will only have dropped by 7 pounds. But you’ll look 13 pounds different.
SEE ALSO: THE FLAT BELLY CHEAT SHEET
If you want less flab and more muscle when you look down at your abs (or where they should be), check out The Flat Belly Cheat Sheet.
It's a “cut the waffle and just tell me what to do” PDF that tells you exactly how to get rid of belly fat. To get a copy of the cheat sheet sent to you, please click or tap here to enter your email address.