I remember it as well. The girl started out to do it to help her understand what her overweight friends went through on a daily basis because she didn't believe "it was all as bad as they said it was". By the end of the experiment, she had changed her view completely and was absolutely stunned at how differently she was treated in a variety of situations because of her fatness. The two situations I remember were shopping at the mall and visiting a club.
Perhpaps if you write to 60 minutes, you can get a copy of that story to show your friends who think that fat discrimination doesn't exist.
Those that don't want to admit that it exists are likely a part of the problem themselves.