I have no actual allergies but I have a weird reaction to morphine so my doctor has instructed me to just say I’m allergic to reduce the chances of having it adminstered.
I have a friend who is allergic to protein however, he’s fine if he acts sluglike after he eats. Any increase in his metabolic rate causes it to enter his system faster than he can deal with it and he needs immediate medical attention. He’s now an expert on exactly which foods have no protein.