It sounds like she's discovered gravity! It's a phase, and I always dealt with it by taking the fun out of it. If Tyler started to toss his food, I'd take it away without a word and offer him something from a spoon instead. At that young age, I wouldn't worry too much about enabling her. She won't forget how to feed herself. All you can really do is make sure you aren't positively reinforcing the tossing by laughing or making a big deal out of it, and give her something else to eat.