1. Make sure your friend knows that you're always there for them, no matter what.
They might not want to talk about their feelings but just knowing that you're supporting them is the best help there is!
2. Your friend might say things they don't mean.
They might distance themselves from you and not make an effort. In the depths of an eating disorder, nothing else matters other than getting thinner. Please be patient with them, it’s hard for them to be rational and to distinguish between their own thoughts and the thoughts of their eating disorder.
3. Your friend might lie about what they have or haven't eaten which can be frustrating.
They are only following the strict rules of their eating disorder and at times, for them, it can seem like lying is the easiest option. You have to understand that this isn't your friend talking, this is their eating disorder, which makes them do or say things they don't want to.
4. Try not to threaten them into eating.
My friends always used to threaten to "tell the teachers" if I ever skipped lunch at school in an attempt to make me eat. This just pushed me further away from them, leaving me feeling alone and unloved. At the end of the day it is down the sufferer to get better and the first step for them is wanting recovery.
5. Keep persevering. Please keep inviting them out. It can be frustrating if an invitation always gets declined. Your friend may find social activities difficult, especially if they involve food. It can be hard for them to escape their "comfort zone" and venture out from a routine in which they feel safe in. Don't give up! Your friend will probably feel guilty and left out for missing out on any social events and will hope to be included in future.
6. Don't treat them differently.
Your friend is not defined by their eating disorder. Although it may try to mask his/her former personality, they are still the same person they used to be. Recovering from an eating disorder is all about finding other things, other than losing weight that make you happy. You can help your friend realise all the other wonderful things in life that are worth fighting for!
7. Set a good example.
Try not to talk about weight/calories/food or exercise. It is easy for someone with an eating disorder to feel guilty. They often compare themselves to others and if they feel that eating more/exercising less than others that will cause excessive guilt and perhaps become jealous of you.