When Celestia took Twilight on as a student, Twilight... well, pretty much worshiped the ground she stood on. So, to hopefully get her little student to see her as another pony instead of some perfect untouchable entity, Celestia tossed aside table manners and acted like a slob in front of Twilight so the filly would realize that she was a fallible, ordinary pony (with godlike magical power and political control over the nation).
Instead, Twilight took to shoving food in her facehole in mimicry of her princess.
since they don't have beef...Do you eat chicken..?
that's always been a question for me.
Not to mention all the adventures she goes through. She may be a bookworm and full time student, but she does a lot of magic and seems to do a lot of running.
Also cause she is the type to focus so hard on studies, reading and all other projects. She probably skips meals. Leading to being extremely hungry when she does stop to eat.
Then again, she probably really like Hayburgers.
(from the next room over) "Dear, are you talking about something?"
"No honey, I'm not talking about anything! "