Well the way I see it there are two sides to it.
Exercise: The constant low intensity stuff uses fat because it's better than sugar for a walk around the block. The high intensity stuff burns through all of the available sugar so you have no choice but to use fat.
Diet: It is nearly impossible to eat as many carbs while being primal as you can on the SAD. Also, fasting forces you to use fat as well.
Hope that helped.
In all of the universe there is only one person with your exact charateristics. Just like there is only one person with everybody else's characteristics. Effectively, your uniqueness makes you pretty average.