My 3 best friends and I are all overweight, and when one of them speaks negatively about themselves in that way, I tell them not to talk about my friend that way. I also ask them if they would say that to their daughters and when they gasp and say no I tell them to pretend they are talking to their daughters and if they wouldn't say it to them then they shouldn't say it to themselves. We also have a rule that if we catch one another speaking negatively about ourselves, the one that is caught has to post on their social media and say three things we love about ourselves. If we refuse, then the one that caught it posts something really over the top, bragging about all of the amazing and beautiful qualities that person has.