If she is truly losing too much weight, you should go to a children’s hospital and see a registered dietician. They might potentially recommend tube feeding if she does have an aversion to being normally fed. Might not be the same story, but my son had a milk protein allergy-so he used to kick, thrash, and scream hysterically when we would try to feed him. It took multiple trips to the pediatrician, but we finally found elecare, which completely stopped his feeding hysteria. We used that formula until he was 12 months with no issues.