Mobility & Medical Supply

Body Muscle

Body Muscle
Does anyone know what kind of doctor would be able to answer my questions about body fat and muscle of the body?

I am a person who loves going to the gym. I have lots of muscles, especially in the thighs and I want to find a way to reduce my muscle mass and body fat at the same time. So I started doing just one type of cardio, running, and now he's doing any more weight training. Anyone knows if I am moving in the right direction to reach my goal. Any suggestions? Or know what type of doctor specializes in something like this?

ask advice of one of the trainers at his gym, but cardio alone will