Intense Cardio Is Key
To spike up the body's metabolism, do intense 45-minute cardio sessions a few times a week. A study published in the Medicine & Science in Sports & Exercise journal showed that an intense cardio session can slash an additional 190 calories post-workout. While research is still not solid on what produces this increase in calories burned, most data lean toward the afterburn effect, in which a period of intense activity causes the body's metabolism to spike and burn off more fat than usual.
Some intense cardio workouts to try: running, indoor cycling, or interval training (like this pyramid treadmill workout).