The Science of Fasting

there is a conventional logic that said to eat something small in the a.m. just to get your metabolism kick started. I would always eat a piece of dry toast and half a grapefruit for this. Has this been completely disproven? What I am getting at is would this maybe work if you were otherwise doing the fast with the exception of this small meal? Or is it an all or nothing.
It's been disproved, along with eating many small meals throughout the day. The only thing eating small meals throughout the day does, it helps people who are hungry all the time control their food intake.

I know how to lose weight, that isn't an issue. I really want to try this for the energy gains and good feeling some describe.

I think the energy gains and good feeling come from the detoxification of your body. But if you don't eat enough calories and (very important!) you don't sleep enough, no matter what you do, you'll feel run down and without energy. At least that's how it is for me.