Sarah, sad to hear that you had such a bad time!

Hope your son is feeling better now!
Well, telling people about food problems...
I wasnīt in such a situation, but I experienced several same situations with alcohol. I am a alcoholic in recovery, and it was hard for me sometimes when people offered me alcohol. I had no idea how to deal with it at first...At the moment I handle the situation like that: people close to me know about my problem. But i didnīt tell everybody. When there is someone offering me alcohol again and again, I say "Thank you, but NO! I am a recovered alcoholic". Most people are shocked and never ask again....
I had dumb reactions as well. But most times, the people who are making fun of you being an addict are those who know deep inside them that they maybe have a problem too. So they react very loud and aggressive sometimes.
For me, it was hard at the beginning. I was so ashamed asking the waiter if there is alcohol in the food...But after all, itīs my health, my life, and I shouldnīt care what others say.
My "I donīt want to explain it to you"- excuse is "No, I donīt drink alcohol. because of health reasons".
My advice...donīt have one.
But i think making a clear statement to your co- workers (without doing soul- striptease) would be helpful. You know, binge eating is an illness. Would you tell your co- workers if you had an other illness (like diabetis. Or a food allergy)?
Kate