How dare she

So I was at a very very good friends house last night babysitting her kids and mine were there playing for awhile to. When I heard from the playroom, the little girl tell Julie that her mom put some of the dress up clothes up in the closet so Julie couldn't put them on because she was to big for them...ok..I understand that. Julie doesn't really fit in the 6x dress up clothes anymore and she doesn't want them ripped. But that is not what pissed me off. As I was sitting there listening, I heard the girl tell Julie that she cant wear them because she is too fat and her mom said that it is because you(Julie) eat too many snacks and too much dinner.....DID I HEAR THIS RIGHT??? So I called Julie into the other room where I was and sent the little girl back in the playroom so that I could talk to Julie alone. I then asked her what was said...she told me and thank god she isn't at the age where it affects her yet...I was pissed and crying because I went through that crap at school when I was a kid and I don't want my child to have to go through that, and for a mom to tell her child that...no wonder kids are so mean. If there parents have no problem saying it, why should they. I then asked the girl to come out and tell me what she told Julie and she repeated the same thing again and then I asked her if her mom told her that and she said yes....this person is one of my very good friends and I am pissed. Now what do I do....after I got home from babysitting at like 1:45 in the morning, I could not sleep but just laid there and thought about it some more and got even more pissed.