The contrast between her usual and fancy appearance and her appetite/eating like a slob is very cute, sexy, and important...

And when she gets so big she's waddling around & letting loose rancid farts in class or even during matches (she has to have her pre-match burgers)

A prideful & rich tsundere american that would absolutely insist on going out to eat after daily matches in the TCG (either a victory meal or something to munch on while strategizing for the rematch), and watching her body expand, straining her shorts + unable to control her gas when she's excited..

Fart alt

AND THUS