My advice, and Heather even mentions this in her book, is to not worry about what others think. You don't really have to even explain it to them. Just simply say that greasy foods make you feel sick and so does dairy. If it isn't necessary to mention, don't. Sometimes when people offer me a cookie or something like that, I just take it and put it in the garbage later. It's just easier like that. This was especially helpful during the holidays. Like Heather says, it's not worth it to you to have an attack at the expense of another person's ignorance.(I hope that doesn't sound harsh)