Eating disorders can happen with or without many illnesses...I guess for many of us it just happens...Has she gotten help with this before?...Did you talk about it with her?...Now that you have caught her, it is really a good thing....She will now know that you are watching her and it might bring the shame factor of this disease front and center....I believe until we face this head on and deal with our own insecurities that we are in for the fight of our life....
If you can get her to see a Therapist...Talk to her...Let her know your concern...You are right this could cause serious bodily damage...Hopefully you can get some help..Take care...
Caroline