"About eating in public -- how do you handle going out with friends and family when all you can eat is a bite or two? At this point, it doesn't make sense for me to even order an entree, but I don't want to stay home either. We do other things, but I don't want to go home right after, say, bowling, when the night will continue for everyone else."
One thing you could try is letting them know that you won't be eating much, but that you would love to go for the company. The less said the better.