The important thing here isn’t to eat breakfast, but to plan how to break your fast every day. I find that intermittent fasting works best for my focus, but like you, if I broke my fast with junk, I’m sure I would much prefer a nap to learning or being productive. I try to eat some high quality protein, with healthy fat and fiber when I eat my first meal.
I believe research is heading in this direction, but can’t take the time right now to cite. Love your article!