Doing cardiovascular (aerobic) exercise such as walking, biking or — everyone's favorite — the Stairmaster is good for you. It reduces heart disease risk by keeping the heart and lungs in shape, helps meet weight loss goals and keeps your whole body healthier.
But if your focus is to burn the most fat, it's not actually the best choice.
You may think of weight training (also called strength or resistance training) as the way to build muscle mass, which it is, but weight-bearing exercises have also been found to be better at burning abdominal fat than cardio exercise alone. Two 15- to 20-minute resistance training sessions every week have positive effects on everything from your resting metabolic rate to your blood pressure and how well your body handles insulin — and it's been found to be better at keeping the waistline from expanding than cardio alone. Combine the two for the best results [sources: ACSM, Winett].