Creatine
 

Creatine, a potent muscle-builder, may also help you burn fat. The muscle added during creatine use increases your resting metabolic rate, stoking your fat-burning furnace. This is critical during a fat-loss phase, when low calorie intake can compromise your muscle mass and lower your metabolic rate. Begin with a five-day loading phase: 15-20 grams daily, divided into 3-4 equal doses. After that, take 3-5 grams of creatine per day with a meal post-exercise.