We've talked about the idea of bonk training before, and I don't claim to know a lot, but know I have done it. Often it was not "breakfast" time, but for various reasons it was still over 6 to 8 hours, sometimes more, since the previous meal. This might have been due to odd work hour schedules or preoccupation with all sorts of things, but sometimes I showed up at the park to skate in a fasted state.
Katholieke Universiteit Leuven
Oude Markt 13
50° 52' 42.5928" N, 4° 41' 59.3592" E