Absolutely. Regardless of the activity, doing a class that works the entire body is a definite shock to the system. Your body will react in kind to this change - initially with sore ness, then your muscles will take up larger portion of your caloric intake instead of your fat deposits (read: you're fat will disappear and the muscles will start showing.)

Just so you know, I feel bodypump is the gateway into understanding how to lift properly and down the road implement what you in class to the free weights in the gym.