Answer:
Busterwaymycat: hairball issues, perhaps? That is a main cause of barfing. Some cats eat too fast and then barf back out what they just ate, and that will often get re-eaten.
I see it happen a lot in my house. What I will say is that I don't see my cats barf out wet food, only dry food, and a lot of times it is hardly chewed at all, so it makes me think that the issue is the food, not the cat, or how the cat eats the food. I have five cats: the two males seem to do most of the (not-furball) barfing.
Mircat: Take her to the vet and get medication to stop the vomiting! She's hungry and getting no nutrition! Why with a cat that sick do you waste time here instead of taking her to the vet?
Jhon M: It can be caused by overeating, eating to fast or worms. Usually with worms they do not eat as much but still vomit. Try reducing the amount of food.