First I just want to say that I'm so sorry that you have to go through this....and if your stepdaughter truly has an eating disorder, please do not be angry with her and know that she is not doing this to intentionally hurt anyone else... whew, ok just had to get that off my chest. Most parents get so frustrated with a daughter who has an ED that it comes off as anger, which only fuels an already ugly situation, but really it's just because they don't understand "how" she could be this way. If you actually want to understand the depths of eating disorders, I would really recommend that you read "Wasted" by Marya Hornbacher. It isn't a book aimed at recovery- it is simply one girl's story of a lifelong battle with anorexia and bulimia..but overall, it REALLY helps provide some explanation for why an ED could develop..and it will let you have a truly eye-opening look at everything from inside the perspective of someone WITH an eating disorder. I've had atypical ED-NOS/Anorexia for the past 4 years, and I recently read this book and was finally able to put some reasoning behind my behaviors, realize that I do have a problem, I cannot deny it to myself anymore, and that there is hope for semi-recovery in the future... even though it's important to also know that an ED is a lifelong battle. Even if someone gets "healthy"..she still must be treated gently, because she'll always be prone to relapsing. *question- how long has this ED been going on? or, I should say- how long have you known about it? If you do decide to buy "Wasted" though, don't show it to your step-daughter or let her read it...it is VERY triggering for someone with an ED, and it won't be beneficial if she reads it while in recovery. I bought my copy at Barnes & Noble for $15. There are other books out there that are aimed specifically at recovery...but they aren't always realistic, and they won't help you understand the way that she thinks. I will let you know of any good ones if I find some though.
I hope that she is open to recovery & somewhat receptive...and I hope that you find the patience to get through this.... be strong!
Feel free to ask any questions if you need help or advice...