You mentioned that there were people with eating disorders in the family. This can be hereditary. Eating disorders are a form of addiction; anorexia, bulemia and overeating, and like any other addiction very difficult to control. Also some people do not have the gene that let’s them know they are full.
Your daughter is almost certainly battling with this problem. There are organisations that can help but I would not suggest them unless she reaches out for help. You are powerless over her eating habits.
All you can do is just accept things as they are, continue to serve healthy food to her. You sound like a loving and caring mother, just continue to support her and maybe have conversations that are nothing to do with food but are more about how she is feeling , how her life is going etc.
Giving my pots a bit of a boost after the winter
Desperately sad story of the assisted suicide of a grieving mother
