I was 42 when I had my first experience with anorexia. I was so sick with it that I was in & out of the medical hospital requiring IV nutrition to stay alive. Kept passing out.

Mine was triggered initially by Prozac & then weight loss becomes addictive.

Yes there needs to be concern but NO, family intervention will probably just make her angry & not create the wanted results. If she is going to a weight mgmt dr, they should be monitoring her weight & BMI.

Sometimes at the lowest healthy BMI people look really thin especially if they have been overweight all their life.

It's better to deal with her in casual conversation than with an intervention IMO.