I train early in the morning. Some workouts I will be on the verge of throwing up and perhaps actually doing it. I would like to reduce this as much as possible so. Do I eat breakfast at 5, sleep until 6 then go workout, eat breakfast at 5 sit around then go workout, or do I skip breakfast all together workout and have it afterwards? I want enough energy to perform but not bring it all up.
Given an adequate dinner the night prior, muscle glycogen levels should be substantial enough to fuel about one hour of effort (according to some smart folks) before the body begins breaking down muscle tissue to make glucose. However, to remind the body that food/fuel is (globally) available, and that exercising in a fasted state will not be the future norm, a small shot of calories prior to exercise is useful. Some would say this should be a mix of all macro-nutrients, others are less strict. I don't think it matters much since the object is not the fuel itself, rather it's the message that is important. The short, intense workout sessions you describe burn little fuel anyway, and only during longer, sustained efforts (>60 min in a fasted state, >90 min otherwise) does fueling and hydration become an issue. So, 100-200 calories on the way to the gym will be fine, from liquid or solid.