Betty
Hi, I hope you don't mind my being honest with you, but your daughter might need to visit a counselor. There might be a psychological reason why she does not want to "eliminate." Please think back to when the problem first began, and see if there was any kind of a traumatic experience in her life! Even babies suffer trauma which affects their bodily functions. And, I will guess it is useless to plead with her verbally or with food, if it's a psychological problem.