A pound of fat is the same weight as a pound of muscle. However, my clients are coached to understand which numbers really matter. As you see with this client's weight, her numbers may have gone up but her inches, mass, and overall appearance have gone down. Note: Body Fat is more ''fluffy' and the muscle is more "dense and compact. "Muscles take up less space in your body, so body weight may go up as you add compact, tight muscle mass.