Unfortunately, in practice it is not that simple. If our bodies attacked our reserves directly, it would be easy for us to lose weight whenever we trained. But the body prefers to take the easiest path, and only when it has burned our blood sugar energy, does the body start burning the energy stored in the fat cells. This is the primary reason why we should not eat directly before our workouts.

In 10% of body fat alone there are 100,000 Kilocalories

An amount of energy enough to run 30 marathons, but that is only theory.