I've seen newspaper articles published on the ill effects of coffee and caffeine in general one day, and on the good things it does the next.

I think you have to drink the things you feel good about. If it's hot cocoa at night, then so be it, if it's oranje juice, fine too, tea, coffee, ... I think it's a very individual thing, although I'm sure there are "RSD diets" out there where it's either permitted or not.