Nope, they didn't.
Biologically we're not meant to eat 3 times a day, every day. That's why we have a lot of health problems, our bodies don't know how to handle so much food.
Meal frequency has been linked to insulin sensitivity in plenty of research.
Don't get too hung up on certain words, I just meant within the scope of how we evolved; our bodily systems are better suited to doing certain things in a certain way. The agricultural revolution happened around 10,000 BCE, yet gluten sensitivity is a very common affliction.