Cat acting strangely?

My cat, Kallly, gave birth to a litter of 5 on May 2nd. Sometimes after, she started to try to eat human food. She even tries to desparetly get to the bread by tearing up the plastic bag that holds it and keeps it fresh. When my mom made breakfast one day, we didn't clean up the greece from the bacon right away, Kally decided to eat it. Even right now, its like she is begging to get to my pizza rolls. I even bet that she'll eat the Beggin' Strips if she was allowed (though the kittens would also probably eat it, for they seem interested in it as well). She has cat food out, but if she gets the option to eat the dog food (the Blue Buffalo), she'll eat it (the cat food from the Blue Buffalo she would prefer, but since it costs so much for something so little, we have to mix it in with a different brand). What should I do, for she has never done this before?