Great article! Although I do disagree with the part about communicating your needs to the host. That’s just inviting an argument. Or the person might try to comply, but not understand in some way.
Better to offer to bring a big dish of XXX to share with everyone. If the host says “But I’m already making YYY,” you can say, “There are so many things I can’t eat, I just want to be on the safe side.”
I know a young woman who has a serious medical condition. I knew that she had some food restrictions, and I asked her what she couldn’t eat. She thought about it and said “Everything.” Great answer!