I absolutely LOVE pinterest!!! I don't really look at foods and such though...i look more at the fitness side of it and crafts.
I think if it bothers you so much to see what she pins...after everything you have supported her through...you really need to stop looking.
Have you tried to talk to her about this? Telling her what you've seen her go through and that she is leading her children down the same path? I know its probably a sticky subject...but she needs to be aware. I think she probably sees what she is doing...but maybe just turns to surgery as the cure. Much like plastic surgery and lipo-suction for those who wish not to do the work themselves. Yes its hard work...but wouldn't you rather know you did it yourself and earned the body you have than knowing you had to pay for it?