I know what I never would do - sabotage my work just because there is 'illegal' food in front of me. I eat before I go and try to eat legal stuff at the dinner. Actually, not many people notice what you do/don't eat....
Most people today will ask if you have allergies etc - tell them! Still, I told my friends once and they did not take it seriously so.....I did not eat. Such is life....

Alina