Don't expect to eat an hour before a workout and have ample muscle glycogen to support a hard workout. If you lift late in the day, you can rely on the fuel you have taken in throughout the day. If you lift early in the day, you may have to rely on what you ate the evening before to support the workout.
Your fuel is very important as you know. You would not make a 1000 mile trip without filling up with gas, so why expect your body to do any different without stalling?
I only speak from experience as it was way embarrassing the day I collapsed in the gym after a HEAVY leg/cardio workout when I did not fuel up (my low carb day).
Just my .02!!
Mrs. TG