It's a common mistaken belief that cardio should be done primarily if you have a lot of weight to lose, maybe even before starting a weight-training program. Actually, the opposite is true, weight training always accelerates fat loss. Muscle is a metabolically active tissue that burns fat. Lifting weights builds muscle and is a necessary part of every fat loss program. This doesn't mean that you need to lift like an Olympic champion. It simply means that weight training is necessary when your goal is fat loss.