Body perception disorders have nothing to do with the rational. Why would you hork down a tub of ice cream, inhale an entire cheesecake, a large bag of chips, three slices of leftover pizza, a giant bag of M&Ms, two cheeseburgers... puke it all up... then rummage around in the garbage for whatever's left so you can start all over again? I once went undercover to several overeaters anonymous meetings to get research on a story... it was both sad and scary. (Most of the people there were recovering bulimics). What was really weird was that even though their lives were a shambles and they couldn't stop themselves from gorging on food, they all had perfect hair and manicured nails... I don't know why that detail struck me so much.
ps... why do you think the new girl is a bulimic?