Time to get to the meat of this muscle myth.

You’ve been putting in work at the gym lately. (Bravo, btw.) At least three days a week, you’re running on the treadmill and toning those muscles with a little weight lifting and Pilates. You’re feeling good. You’re also eating right. Then you step on the scale one morning and what the #@&?! You’re three pounds heavier?!

Oh wait. It must be from all your brand new muscles, because muscle weighs more than fat … *right*?

Sorry to break it to you, but this is a myth. Think about it: Whether you have a pound of feathers or a pound of brick, a pound is just a pound. The brick just seems heavier because it’s dense and takes up less space.

The same rule goes for fat and muscle. Muscle seems like it weighs more, because it’s denser, like brick. On your body, muscle takes up much less space than fat too. So, if you gain five pounds of muscle, you’ll look leaner than if you gained five pounds of fat.

Even though packing on muscle can contribute to weight gain, it’s much harder to gain muscle than it is to gain fat. For average folks doing a regular strength-training routine, building a pound of muscle may take several weeks to a month. If you’re training like John Cena, however, you may be able to put on muscle weight a little faster.

As for that overnight three-pound weight gain? It’s likely temporary. Day-to-day weight fluctuations—whether you’re trying to shed pounds or not—are totally normal. 

If you’re trying to get fit, try not to obsess about the number on the scale. Instead, focus on how you feel (a.k.a., stronger) and how your clothes fit (a.k.a., looser).