What burns fat in a short period of time?

On average, you burn fat relatively more body fat by walking than by jogging, as harder workouts require quicker energy, and the body fuels them mostly with fast burning sugars. It turns to slower burning body fat for easier exercise. So if you use a heart-rate monitor, workout with your heart rate between 65 and 80 percent of your maximum, which approximates, roughly, to 220 minus your age. Our bodies burn a higher percentage of fats than carbohydrates at that pace. But if weight loss is your goal, bear in mind that you burn fewer calories overall during a 30 minute walk than a 30 minute jog.