The best fat-burning exercise machines in the gym are those that burn the most calories per training session. While aerobic training equipment like the treadmill, elliptical trainer and stair climber are commonly considered the preferred machines for fat burning, resistance training equipment should not be overlooked as fast-track gear for fat loss.

The Energy Balance Equation

Regardless of what type of exercise you do, weight loss and fat reduction are ultimately a product to energy balance. When you expend more energy, expressed as calories, than you take in, you lose weight. Any type of physical activity tends to tip the balance in favor of weight loss. (reference 3) During long-duration, moderate intensity exercise, a greater percentage of energy is drawn from fat stores. But exercise of the same duration performed at higher intensities burns more total calories and more fat than lower intensity exercise. (reference 1, 2) A study of obese men published in the "International Journal of Obesity" found that regular high-intensity exercise has a profound effect on decreased body fatness. (reference 2)

Cardiovascular Equipment

Cardiovascular equipment like stationary bikes, treadmills and elliptical trainers can be effective for fat burning during rhythmic low to moderate intensity activities lasting longer than 20 to 25 minutes. (reference 4) But you can maximize your results in a shorter period of time by interspersing high-intensity bouts of all out effort into your workout at specific intervals. A study of recreationally active subjects published in "Applied Physiology, Nutrition and Metabolism" found that high intensity interval training significantly increased fat metabolism and improved body composition in subjects after a six-week training program of three sessions per week. (reference 1) To maximize your results on the treadmill, try interspersing intensity intervals at a 3:1 ratio, walking or jogging for three minutes, then sprinting for one minute. Repeat the entire cycle seven to 10 times.

Resistance Training Equipment

The weight machines in your gym's circuit can expedite your fat loss while sculpting a strong, toned physique. According to exercise scientist Len Kravitz, resistance training uses high amounts of energy, and an elevated level of energy expenditure continues for hours after your exercise session. What's more, adding more metabolically active lean muscle will boost your basal metabolism, leading to a greater total daily caloric expenditure, even at rest. More lean mass means a lower body fat percentage. And resistance training has many other health benefits including increased bone density, increased strength, improved cardiovascular fitness, decreased resting blood pressure, decreased insulin resistance and an improved blood lipid profile. (reference 5)

The Best of Both Worlds

To maximize your fat loss and get a great body, consider combining resistance training equipment and cardio machines into one workout by interspersing high-intensity cardio intervals between each weight training exercise. For example, immediately after using the seated bench press, do an all-out sprint on the treadmill for one to three minutes, then move on to another resistance exercise followed by another high-intensity cardio interval. Repeat until you have completed the entire circuit.