The first page address has good info about mother's diets and breastmilk. The second is to their list of calcium sources which are nondairy (in case the baby seems to have a dairy sensitivity or in case the mother does, or if the mother is a vegan) if you are concerned about getting more calcium.
http://www.kellymom.com/mom-diet.html
http://www.kellymom.com/food-sensitivity.html#list

mainly, your breast milk will be best for your baby even if you only ate junk foods (as long as you're not deprived of protein and calories, or starving personally... and even then it is the quantity that would be affected and not so much the contents/quality)