Type 2 diabetes is a growing public health issue and one component of Type 2 diabetes is 'insulin resistance" - the ability of insulin to work less well. The skeletal muscle is one of the largest users of sugar in the body, when the skeletal muscle is "insulin resistant", this contributes to diabetes. There is some evidence that the amount of fat in the skeletal muscle is related to the amount of insulin resistance. We are asking people to participate in a study to look at the amount of fat in muscle and how this fat amount changes with exercise. We hypothesize that heavier people will have higher amounts of fat and deplete this fat more slowly than lean subjects.