Typically what you eat (or drink) will end up in the next feed. So say you had something you know upsets the baby you can always pump and dump on the following feed. I am wondering what foods you are worried about. You really can eat anything you want, even spicy foods. I am a nursing momma and I was more concerned about eating processed foods. Never even considered eating fast food then feeding the baby. Of course try to eat organic as much as possible. Hope this helps. Most important thing is not to quit or give up. You are giving your baby a true gift!