First fast update: the morning after
Woke up ~3am with, of all things, ankle pain. Cramp? Dunno. May've been fast-related, maybe not. (Definitely wasn't hydration related; I'm positive I was sufficiently hydrated! :) Probably was fast-related, though, as I don't recall ever having this happen before. If I do this again, and wake up with leg pain again, I'll think about vitamins while fasting.
Aside from that, no worries so far. I'm not, like, ravenously hungry or anything. I'm enjoying my coffee with cream on a (very) empty stomach. :)