Shift your language from "food" to "medical"
Why it works
When you use culinary terms, people treat your situation like a menu preference. When you use medical terms, it reframes the situation as a health necessity.
What to say
Instead of saying: "I can't eat dairy, so please make sure there's no butter in that dish."
Try saying: "I have a medical condition where my immune system treats dairy proteins like a toxin. Even microscopic amounts can trigger a severe systemic reaction, so I have to be incredibly strict about how food is prepared."

