Top 10 Fitness Myths
Muscle weighs more than fat. #9
In my experience, the layperson tends to believe this myth mostly because he either read it or heard a fitness or health professional say it. It sounds reasonable anyway, right? Fat is just this light, fluffy substance, while muscle is solid as a rock.
This one reminds me of the joke that goes, Which is heavier, 1,000 pounds of feathers or 1,000 pounds of steel? We used to tell that joke as kids. It is funny how many people will pick the steel, when, in fact, they weigh exactly the same. We hear the words "feathers" and "steel" and think about the density of the material. It takes a small piece of steel to equal the weight of a whole trash bag of feathers. But if you can get enough feathers, you can make 1,000 lbs.
The same goes for fat versus muscle. First of all, let's understand that "solid" muscle is actually 70 percent water. Sorry to have to say that, but it's true. It's the protein (the contractile elements of the muscle) which makes the difference in that remaining 30 percent.
With that, muscle is more dense than fat. So, a pound of fat takes up much more space in your body than a pound of muscle. This means that when you begin a good training regimen, you may in fact gain weight because you will lose a bunch of fat and gain muscle. Believe me, this is a good thing, because you will then be leaner and smaller in circumference.