It isn't physically possible for someone to eat something and then pass it right away - some food (spicy foods, etc) might give you diarrhea, but you're not going to pass what you just ate whole - going through the digestive track takes hours.
If she's eating meat and then passing it undigested the next day, she should see a gastroenterologist. She could have a serious digestive disorder, like Celiac or Irritable bowel syndrome.
Or, is your daughter a teenager? Maybe she wants to be a vegetarian and is afraid to tell you? The vegetarian diet can be perfectly healthy.
:wave: http://www.mypyramid.gov/tips_resources/vegetarian_diets.html