Breakfast. Because it is the first meal of the day and I don’t try to segregate my food by “Meal Type”. If I have it and I am in the mood for it when I wake up I am going to eat it. This applies to girlfriends as well.
I vote for lunch because if you get up late, you’ve already missed breakfast or can just skip it and go straight to lunch. Plus many breakfast options are boring compared to lunch or dinner choices (like cold cereal or oatmeal for example). Also, most things you eat for lunch make perfectly acceptable dinners. Lastly, if you eat out, the lunch menu has many of the same things as the dinner menu for quite a bit less $. There you have it.