My mom dog sitted for me for a week, now my dog won't eat?

I was out of town for a week and my mom watched my dog while I was gone. My dog never ate too well, but she always finished her food. When I got home my mom told me that my dog "wouldn't eat", and she mixed peanut butter or banana or cereal with food every time to get her to eat. Now my dog spitted out the food when I tried to get her to eat. Should I just let her starve for a few days before get worried or has my mom permenantly messed up my dog's eating habit?