depends what works for you..... you should be ok doing short runs when you get home from work (unless you're diabetic or similar).... if they get longer you might want to think about a snack mid afternoon just to keep your energy levels topped up.
Exactly. My club mate always devours jam butties immediately prior to a race. He reckons he can't run on empty and jam butties are the best thing for putting fuel in his tank!
Generally after eating I like a couple of hours to pass before I run - or before I race - but I've been known to take fuel on board 'during' longish training runs or in a race like 'The Three Peaks'. So circumstances come into the equation too.