My 18 month old has recently learned how to ask for some of her favorite snacks (cheese and graham crackers). It was cute at first and we would give her the foods because she asked nicely, but within only a few days she started demanding those foods pretty much all the time (if we tried to give her another snack, during meals, etc). So we had to start saying no and now she will become absolutely hysterical if we deny her. It's gotten to the point where she will roll around on the ground screaming for a full 15 minutes if we don't give her a cheese stick, and it's driving us nuts. When this happens at meal time, she will also refuse to eat anything else until she gets her snack first.

Has anyone gone through something like this and have tips? We don't want to cut her off completely from her favorite foods, but we also don't want her demanding them constantly. DH is also worried that if we give her what she wants when she tantrums, it will only reinforce that behavior (I've been known to give in to stop the screaming...oops).