I ran out today without eating due to running late. There was a pretty good headwind the whole way, and between trying to make up time and sprinting to catch all the lights where I would usually get a breather I was totally toast by time I got in. I had to sit in the grass by the parking lot and take down a gel shot before going in the building, got some "you alright?s" from my co-workers.
I don't have a long commute at all, but I guess I don't have much fuel stored in my system first thing in the morning, so I need at least a energy bar to get going.