Eating or drinking ready energy sources throughout the morning and early afternoon: "I'll hold out until lunch at x" has been a terribly limiting habit I've struggled to break. Ditto "I'm not really hungry yet"
Right now this consists of making three sandwiches the night before and freezing them, eating one on the often lengthy train trip to the ride and the other two in quarters or bites through it. Also, lots of sports drink mix with added electrolytes. That's what let's lets me ride all day, potentially very different from a shorter ride and drastically from a commute or fitness ride powered by incidental calorie intake.
Even with this I still lose steam late afternoon, typically making it up when I'm sufficiently fueled again and the sun starts to get lower in the sky.