I was referring to the expressions "Breakfast is the most important meal of the day". Also, different activities are adapted to different things. Even without one ethnicity, there might be differences (for example, slaves vs warriors). I subscribed to the Warrior Diet [0]. According to the author Ori Hofmekler, slaves were eating all day long while warriors were only feasting at night.

[0]: https://en.wikipedia.org/wiki/Warrior_diet