With my work schedule, I have to train first thing in the am (5:30a - earliest my gym opens). I usually don't eat, just because I don't feel like eating that early. I train heavy (no cardio though), and seem to be okay as long as I limit the length of my lift. I should drink a little protein before, but so far (knock on wood) I've been able to handle it. I still prefer my weekend training though, which I do after I've eaten.