Exercise Cuts Fat, But Maintains Muscle Mass

One big challenge in getting ripped while you’re training with weights is how to lose fat without decreasing muscle mass. People invariably lose muscle mass when they lose bodyweight, which causes decreases in strength and aerobic capacity. Researchers from the Washington University School of Medicine in St. Louis – in a 12-month study of middle-aged adults- found that people who lost weight through caloric restriction decreased 3.5 percent in lean mass, 6.9 percent in thigh muscle volume, 7.2 percent in knee flexion strength and 6.8 percent in aerobic capacity. 

People who lost weight through exercise alone lost 10 percent of bodyweight, but had no decreases in muscle size or strength.  They also improved 30 percent in aerobic capacity, expressed relative to weight. 

Good advice for Arnold wannabes who are cutting up while pounding the iron is to lose as much weight as possible through exercise alone while consuming plenty of good quality protein before and after workouts.  (Journal Applied Physiology, in press, published online Nov 9, 2006)