When it comes to the best workouts for weight loss, neither weights nor cardio can completely move the needle on their own. Interval training is the best way to shed pounds, increase your metabolism, improve your cholesterol profile, and improve insulin sensitivity. At the gym, sign up for a HIIT class, or turn your favorite aerobic exercise, (running, biking, even walking) into an interval workout by adding periods of intense speed (start with 30 to 60 seconds) followed by periods of rest (normal speed) for the same amount of time. Do this six to 10 times to complete a fat-slashing workout. As you get better, slowly increase the amount of time of increased intensity.