I know this isn't the same but I used to hide food (think casserole in pockets) if I didn't like it. I would also make myself sick if i was made to eat something i didnt want to. I didn't do it in secret. It was there and then at the dinner table in a display of "I'll show you" to my parents. I am not sure that is too unusual I can see why you are concerned though.

Maybe look on Eating Disorders Australia's website for ideas ?

There are also paeds who specialise in this sort of thing.