Energy that lasts ALL DAY!
When you use fat for fuel you have tons of energy.
Using carbohydrates for fuel is like burning pine needles in your campfire. They burn quickly and then go out! (That's why you are hungry all the time)
Using your own fat for fuel is like burning a dense log in your campfire. The fire burns for a long, long time and provides a steady source of energy. (You don't get a sugar crash.)