I'll always have something before I leave the house, even at 2-3am, as I feel it helps me become more alert, and happier in and of myself at such a grim hour. Normally a decent bowl of a relatively healthy brand of cereal, or something else that's quick to sort out. I may then not have time to eat much until at least a few hours later, or depending on my commute and subsequent work, much later than that! In that case, the energy is also important.
It's all part of the routine now, and unlike many people, I've never felt unable to eat at that time, which is lucky. I know loads of people really struggle with wanting to eat before about 7am ish. I try to refrain from drinking coffee until I've had some food and walked to the station or something, to make sure I don't become too jittery, but I'll still end up drinking it at some point!