Studies have conclusively shown that a group of subjects who sprinted for 30 seconds (for 3 sets with 4 minutes of rest) three times per week lost twice as much body fat as another group that jogged for 30-60 minutes three times per week.
To quote Dr. Jim Stoppani, this is possible because:
You burn more fat the rest of the day than [during] your workout.
Your body reacts to exercise far less during the workout and more so after the workout when it is recovering during the remainder of the day, and when sleeping.
Recovery is a fuel-burning process, and the more intense a workout, the more fuel (i.e. fat) is burned during recovery.
Dr. Stoppani reiterates that:
Fat loss isn’t happening the moment you’re in the gym; it’s happening when you’re not in the gym.
If the intensity of a workout is too low, then the duration of the workout doesn’t matter since the recovery period will be minimal, and therefore fat loss will be minimal.
On the other hand a shorter, more intense workout methodology such as High-Intensity Interval Training will result in more fat being burned since the recovery period is longer.