Bullemia is a proper medical condition. The sufferer eats a whole load of food, nice food that makes em feel great, and then vomits it all up again. Half an hour is a good waiting time cos then it all goes mushy and is smoother to eject, apparently. Lots of people suffer from it, mainly girls. It can be brought on by lack of self confidence or a paticular incident in which they were made to feel completely out of control like rape or something. Once the condition sets in it becomes like a bad habit and can last for years and years.
The idea of ejecting all the things eaten gives a sense of control over the food and thus oneself.
Often kept a deeply guarded secret one would never know someone does it unless you know them very well.
It, obviously, is not a good thing to get into. It can lead to stomach problems and the wearing down of teeth and premature aging.
Think of a very pretty girl who likes to be very pretty and kinda lives off being very pretty. It is the most important thing in her life. but Then one day age kicks in and so does a love for chocolate and suddenly chocolate becomes the most important thing in her life but she doesn't want to become fat (cos TV hypnotises us to thinking Fat is Bad) so she thinks i wanna eat all this chocolate and not become fat, hmmmm i'll eat it then throw it up! that way i get the best of both worlds. This becomes ingrained in her daily life and soon bullemia is a big problem.