As she is a foster daughter...can you find out what her life was like before you got her? If she was starved and feces was her only source of food? Was she sexually abused? Was she brain injured in someway? These are the first questions that pop into my mind.
Then was she starved for attention and has learned that doing that gets your attention? If it is a "choice" behavior...then there is some "reward" she has learned that comes from making that "choice". If it's a "survival" behavior...then reinforcing her survival no longer depends on this behavior...should extinguish it. If it's a brain injury...what she thinks is food isn't...Does she eat normal food...in normal ways?
These are all things to investigate in order to treat.
at 7:09 PM on Dec. 1, 2013