Is she taking antibiotics? That can make her tummy feel icky. There are certain medicines that will give her a better appetite. Also, is her nose stuffed up? If so, that may be why she eats the treats that she can smell, but not the food, which isn't so "smelly". I've heard that you can use Neo-Synephrine "baby noses" drops to unstop their noses. Not like she'd be too pleased with that, though.