I had a job in an ice cream shop when I was in my teens. I weighed 120 pounds at 5'2". Scooping ice cream for 30 hours a week is a work out and guess which arm looked sleeker and slimmer? The one that did most of the scooping. I know I didn't burn fat in that arm, but muscle tone can make a world of difference even under a padding of extra weight. I think too many people ignore how much of a visual improvment they can get from toning because they're obsessed with the fat.