I tell people that I do not eat M&Ms because I am allergic to peanuts.
M&Ms do not have peanuts in them now, but they did back when candy bars were ruled to have to have so much nutrition in them. (BTW, M&M denies this fact)
Today, if I tell people this, they assume that I meant peanut M&Ms (the ones in the yellow pack)
It sucks being allergic to things. When brought up, people are usually way too paranoid about it, or way too thoughtless.