Banana. If still hungry then apple. If still hungry then banana. Repeat.
Fruits are good for you. Sugar in the morning and they hydrate you aswell. Might be a good idea to have a sandwich or something as a snack before lunch.
Op was asking for a fast breakfast really early in the morning. I think its not a good idea to eat something very heavy just after waking up. That's why i recommended a sandwich as a snack some time later before lunch.
Fast as in the non-eating time since last meal or fast as in quick? I might have missed the original question... If it's the latter, there's plenty of quick, filling meal items in the morning. When I was serious about weight lifting, I would drink a protein shake 1-3 times a day to supplement muscle-building.
As for the former, intermittent fast-ers are adamant that anything other than water, plain coffee/tea will break their fast and provide less benefits.
I don't know, but wonder if there is a scientific basis for this. If you're avoiding eating something that's going to fill you up (ie protein), my reaction is kind of "why bother"...
Idk about that. I make biscuits and gravy on the weekends sometimes and always feel good for the rest of the day. The lighter stuff I eat during the week leaves me dragging by mid morning.