Earlier quoted context omitted.
I'm the opposite. If my brain has to engage before 10am the day's a waste. If I "ease into the day" then once I've dealt with the world on fire stuff about 11.30 I'll power through and before I know it it's 9PM and I've been massively productive.
This is me as well. My brain is useless until close to lunch time. After lunch I start feeling productive and this feeling begins to steamroll into the evening. When I am allowed to structure my day I don't even plan to start work until 6pm and can maintain great focus from then until 1am. Admittedly I imagine my ADHD has much to do with that and the habits I formed to cope with it as a child.
I think it is breaking for lunch that does it. When I didn't have any team mates in my office and I'd just eat at my desk I'd still get good work done after eating. Now I have team mates in the same office as me and we go for a "proper" lunch break - something about stopping and then having to go back to work I guess.