Here is my advice for overweight daughter: although it sounds like it is important for you to help your daughter lose weight by making healthy choices, you need to teach her how to do so in a way that nourishes her, rather than trying to humiliate her into doing so by calling her fat.
If you use a negative approach, she may end up resenting you and overeat just to spite you. Worse yet, she may end up hating herself.
The choice to change unhealthy habits should spring from love and respect for the body.
Raise your kids to love and respect themselves and to develop their natural strengths so they can use them to make a contribution to society and lead a fulfilling life. Learn how to get started by reading Keepers of the Children