[@Shadow Daedalus]At first it's a literal simple carbohydrate, like a sugar, so it will give you a boost of energy, but once your blood sugar gets too high, it starts getting stored.

The power ranks are technically done on a 1-10 system, with a 1 being "with enough effort, I can do something" and 10 being the limit of what a human can do, but not all powers fit well into that.  Just list the strength based on the limits of what you can do with it.

Edit: I'm guessing the S-rank in your CS would be something like Class 7 or 8, with Class 8 being around where people start considering you a master.  Witchcraft and sorcery can technically go beyond class 10, as can the abilities of certain races (Awakened (limitless energy from heaven) Angels, some spirits, gods and demi-gods, etc).  Class 5 is about average.