Here you go, the origins of our meal times ...

http://www.bbc.com/news/magazine-20243692

Really, eating 3 squares a day is a product of industrialization. So we've only been eating them around 100 years. Not long in the 10,000 year history of modern man. So don't be afraid to break traditions. Don't get yourself tied up on what a breakfast food is or how many courses should be served for dinner. Eat for your goals.