I find that my absolutely most productive time is right as I wake up, especially if it's early--5am-ish till probably 7am is that sacred window of time.
I always do things that I really want to do and are meaningful to me in that time--as opposed to things I "have" to do or are urgent. This often involves programming personal projects or studying a programming book. I find that if I promise myself that I'll do those things that I love first thing, it's much easier to wake up (really) early and especially get out of bed--the motivation is critical for me.
Problem is, that motivation is partially lost as soon as I put any routines between waking up and getting to work--such as eating.
So I'm looking for the compromise on that trade-off--how long should I go without eating at all, or drinking water for that matter, or taking a break? For how long should I leverage that motivation by working uninterrupted, before the fall on productivity offsets the motivation boost?