When it comes to losing weight, not all exercises are created equal. And although a healthy exercise routine includes a variety of moves, some activities are far more efficient than others at burning calories. This is a crucial point because the only "trick" to melting body fat is burning more calories than you eat -- and considering you have to torch 3,500 calories to lose just one pound, your exercise choice can make a big difference in speeding up or delaying your results.

Cardio Power

In a recent study headed by faculty at Duke University Medical Center, cardiovascular exercise was shown to burn the most calories and trumps strength training for weight loss. Participants in the study were assigned to one of three groups: a cardio group, a weightlifting group, or a cardio and weightlifting group that worked out twice as long as everyone else.

They found that the cardio group, who mainly worked out on treadmills or elliptical machines, lost an equal amount of weight and fat as the cardio-plus-weights group, despite the shorter workout time. The weights-only group lost the least amount of weight.

Interval Training

For serious calorie incineration, pump up your cardio routine with interval training. Do this by exercising at a moderate rate for a few minutes, going at full-steam for a shorter interval and then returning to the moderate rate to recover before repeating the cycle.

One study showed that men who cycled gently on a stationary bike for four minutes, sprint-cycled for 30 seconds and repeated for five intervals at each intensity burned 200 more calories than usual in the 24 hours after their training session.

You can do interval training on a bike, elliptical machine, Stairmaster or other cardio equipment, or you can simply alternate walking or jogging intervals with running or sprinting ones.

Building Muscle

Even though weights, push-ups and chin-ups won't put you on the fast track to weight loss, strength training is still important for weight management. When you build muscle, you effectively increase your metabolic rate because bigger muscles burn more calories, even as you sleep.

Everyone naturally loses muscle mass with age, and this is a big part of the metabolism slowdown that comes with middle age. With regular strength training, you can help perk up a sluggish metabolism and prevent weight gain.

Eating for Weight Loss

Although exercise is a key component in any weight-loss strategy, it can only take you so far. You can usually knock far more calories out of your day by reducing food intake than by working them off with a moderate exercise routine. Cutting 500 to 1,000 calories from your diet will make you lose one to two pounds per week; use exercise to boost results and promote good health.

If counting calories leaves you frustrated, focus instead on eating lean, whole foods. By filling up on fresh fruits, salad veggies, tofu, egg whites and whole-grain bread and crackers, you won't have room left for high-calorie fare that leads to calorie overload.