Nelson hit the nail on the head... again. Cardio doesn't magically burn fat while weights just build muscle. Intensity in the gym with 30 seconds rest in between sets will get you there. If you want to lose fat stay away from biceps/triceps. Concentrate on chest, back, and legs and watch the pounds disappear. If your set on cardio, try jumping rope like satch said, or play basketball. Running on a treadmill, regardless of results has never appealed to me in the least.