What should i feed my 1.5 year old rat?

I currently feed her Forti-Diet Pro Health which are the little nuggets but I think she doesn't like them anymore! She just takes them out of my hand from the top of the cage and then goes to the corner and puts it in the stash of her other nuggets which i don't see her really eating anymore but she used too! Helpp what type of food do you feed your rat(s)?