Everyone's opinion may be different and it is obvious that no two bodies are alike, but here's what I do:
Pre-workout, I have protein and complex carbs or protein and fruit. This could be something like a protein shake and oatmeal or a fruit and protein smoothie (protein powder, berries, or whatever other fruit I want in it, and ice).
Then, post-workout, I will have pretty much the same thing.
It works out well because you get energy before your workout and optimum recovery afterwards.
I don't personally advise working out in a fasted state, though some people believe it is a good idea. The smoothie you ate didn't hinder your workout; just add some protein to it next time.