You may think you know what the gag rule is, but I can assure you that unless you've been pregnant and suffered through morning sickness, you really don't.
Here's my definition:
If you're grocery shopping and some particular item makes you gag, don't put it in your cart. Instead, search for those few elusive foods that sound even remotely appealing and buy those. This actually makes for easy shopping, since you can skip over pretty much the whole store. Unless, of course, you're feeling generous and decide to buy something for the rest of your family.
Oh, and the pregnancy books that talk about eating a wholesome, balanced diet? Phooey on them. I'd like to see them try and choke down a healthy meal while trying not to vomit. I mean really, how are you supposed to eat well when the only things that sound good are not so good for you?