My oldest was like that and we still deal with it. How is your child on weight gain / loss? She is failing to thrive? If not, and she is gaining the best thing to do is focus on good eating habits! That is sooooo key. If you do the "drinks" that will decrease her appetite and creat bad eating habits then you will just have to deal with this all over again everytime you take away the "drinks". It is true that their bodies can get addict to the calories from those drink and refuse to eat. What I had to do with my son, eat every couple of hours (good stuff - and with fat nothing low skim milk or reduced calories) like 4% cottage cheese and add stuff to everything she eats. Past is fine, but not very nutrious, add pease and tuna in very small bites. Yogurt and shredded chicken mixed togher is great as well (whole yogurt). Take away fills (snacks like cheerios, and goldfish, and too much milk and juice are fills can act as fills also). I hope this helps. As a mom who has been thru this... it's hard and you worry, worry, worry. But, just a few more tips. Don't make food a big deal, the bigger the deal the more difficult it is to develop good habits, they will rebel just to rebel at that age. You are going to get the most luck in the first 5 min. if after 5 min. she won't eat any more don't push it, it's past the toddler time-limit. Just try again in and hour or two. Don't ruin meal with snacks just because she is open to eating, not developing good habits. Again, this is all if there is not an issue with thriving. If that is a concern, get with your dr. and work out a plan for intervention and then address the eating habits after the danger has passed. Also, just one more thing. A lot of weigh and size is genetic. Where you skinny as a child, was your husband? My dr. said "it's not a sin to be thin" after all his dad is 6'3" and thin and I'm 5'6" and 110 lbs after 2 kids, it's just genetics to some degree. My son will never be at the 50% weight, he will most likely always linger in the 3 - 10% and that is healthy for him. Doesn't mean, it doesn't freak me out some days:)
Hope that helped! I realize I probably have tons of errors and typo's - Sorry, I have lot's of kids stuff going on all around me. :)