Actually back then you would've eaten whenever you managed to make a kill. This could mean twice a day or once every 3 days, depending on whether you can find anything.
The reason we all eat at night is because it's usually easier to get a meal together later in the day (work, school etc.). The benefits of fasting minus the trouble for being late.
In all of the universe there is only one person with your exact charateristics. Just like there is only one person with everybody else's characteristics. Effectively, your uniqueness makes you pretty average.