Angie, all the advice I am giving you is based on a dietician's advice to all the kids I work with. She works with a population of teens that are all on different meds (Concerta and Strattera being two we use often) and she gets almost all of them on an even keel eventually. That doesn't mean I know what I'm talking about, just parroting her. LOL.
Goodweed, your advice to Angie to seek professional help is the right one. None of us here are uniquely qualified to help this young lady out.
I personally disagree (respectfully Goodweed) with the tofu suggestion, just because I know my own skinny minnie would not even LOOK at a smoothie of that description. Yogurt is low fat to begin with but contains the essential fatty acids necessary to brain development in younger folks. Go with that and the berries GW suggests for those times that she doesn't have much appetite.
You're only given a little spark of madness. You mustn't lose it. Robin Williams