Fasted cardio is incorporated by many athletes and celebrities to burn excess fat. When doing fasted cardio your body will be forced to use fat as an energy source. Fasted cardio will tap into stubborn fat areas of the body more than any other form of cardio. These includes your lower abs and back for men and hips and thighs for women.
A study was conducted on the fat burning affects of cardio on an empty stomach compared to men who had repaired glycogen levels one hour beforehand. After twenty minutes of exercise the amount of fat burned was higher in the fasted group. These results continued for another hour of exercise. The fasted group also had a higher quantity of free fatty acids available in the bloodstream. This study proves that more fat was burned by the group that performed the cardio on a fasted stomach.
You will not burn of hard gained muscle when fasted because during a fast and during exercise your body releases human growth hormone which prevents muscle being used as an energy source. Fasted cardio is one of the most effective ways of burning fat.