I would say before. But important factors to consider are...

1. What is your fitness goals?(are you trying to build muscle or lose weight)
2. Are you going to do cardio, light weights or going heavy?

Knowing the answers to these question gives you a better understanding what to eat.

Having a good juice like carrot and apple,or protien shake which is light and fills u up x

It all depends on how things feel for you but here's a helpful place to start :

http://www.onlyinfographic.com/2011/the-complete-guide-to-workout-nutrition/

Thank you. Guys ✌