I normally eat two meals a day: lunch and dinner.
I find that if I eat a breakfast, I am just as hungry, or maybe moreso, by lunchtime.
Good questions about what is traditional. Apparently, if you go back far enough, nothing. Nonetheless, eating more than the Roman one-meal-a-day in the last century seems to have led to 1) healthier babies 2) taller people. Healthier babies = less infant mortality. That could be more related to what we eat rather than when. Growing up in Montreal in the middle of the last century, the schools then gave us an hour and a half for lunch which we called dinner. Evening meal was smaller and called supper.
One thing that always strikes me is the nature of the "Irish breakfast"; it wasn't until the past two or three decades that any typical Irish person could afford to eat so much meat in one meal, and certainly not for breakfast. The "full Irish" is a modern invention.
In fact, in my grandfather's time people were so poor, and eating meat so exceptional, that people would eat what was called "potatoes and point". They'd eat a big feed of potatoes, and point the potato on their fork at the piece of meat hanging from the kitchen ceiling, as if to symbolically imbue the potato with the meat's sustenance.
Really interesting article. I didn't know just how different the attitude to food was in olden days, than what it is now.