How come when you're inactive your metabolism slows down?

You boost your metabolism through excersise. It ha to be arobecic. Dance, jumpiming rope, and things that get your body moving. Weights are for muscle. Fat burning---get up and move it--I like to move it move it, I like to move it move I like to move it move it----MOVE IT!!!! You gain weight on your off times because you are eating the wrong food... Stay away from the white carbs...