Breaking up with breakfast
I used to feel the same way as you do, as in your post. I’d get up 40 minutes before leaving for gym, as, being a breakfast person like you, I could not do without breakfast. That was before I started running — about 2 years ago.
I started running in summer and I like to do it as early as possible, starting just before dawn. I couldn’t stand getting up 30 minutes earlier to eat, so I just started having a glass of water and heading out the door.
I found it quite easy to keep up the effort, to my surprise. I even do a massive set of hill sprints and stair climbs — 18 sets — one day a week as I run the 5km. Every other day I do a Fartlek set of exercises at the 4km mark.
To your point about burning muscle protein if we use up all our glucose stores — our liver and muscles have generally stored enough for 60–90 minutes of hard exercise. After all, it’s not powerlifting!