The Claim: Adding an extra pound of muscle to your body causes you to burn about 50 more calories per day
Muscle tissue only burns about 5 calories per day. This is a well established scientific fact that you can easily verify with a quick browse through the scientific literature. The most metabolically active tissues are your internal organs (heart, liver, kidneys, brain etc).
There is a persistent factoid that 1 pound of muscle burns all kinds of extra calories and a common number cited is around 50 calories per pound of muscle. I’m not sure where this number comes from because there isn’t any scientific evidence to back this up.
If weight loss is your goal then adding muscle isn’t going to help. You gotta eat less calories.