At lower intensities, you burn a greater percentage of calories from fat than
carbohydrates, and at higher intensities you burn a greater percentage of calories from
carbohydrates. High intensity aerobic exercise can use as much as 65% of the body's
energy needs in the form of carbohydrate. The most important issue for fat loss is not the
ratio of fat to carbohydrate burned, but the total number of calories burned and high
intensity aerobic exercise burns the most calories!
The lower the intensity, the lower the total number of calories burned and the
higher the intensity, the greater the number of calories burned. High intensity cardio also
raises your metabolic rate after the workout to a much greater degree than low intensity
cardio. That’s why high intensity cardio is better, provided that you can maintain it for a
long enough duration to burn an appreciable number of calories.