There are some «old wives tales» about foods you shouldn't eat while breastfeeding. (womenandinfants.org)
You can read about how many extra calories you need to eat while breastfeeding here and my experience with losing weight while breastfeeding here. (exclusivepumping.com)
When eating while breastfeeding you want to make sure you are eating about an extra 500 calories a day. (checkpregnancy.com)