DD 16 - food issues & friendship

[Changeissometimesgood]

DD is one of twins, and is causing me concern . For about a month now, she has not been able to eat full meals. She'll have a couple of bites of toast at breakfast, eats whatever she eats at school, and then in the evening will try to eat but says she feels full (sometimes saying it's in her throat). We have been to the doctors with other issues that we thought may have been linked but aren't. The doctor asked her if she wants to eat and DD replied yes. Doctor has suggested gaviscon but DD doesn't think she has indigestion.
So the reason I mention a friend - she has a friend who she regularly falls out with and to me appears to be controlling. When I've heard DD speak to her she turns submissive and this isn't like DD - she is normally gregarious and laid back. I'm just wondering if this girl is causing her anxiety.
We are all worried about her - even her sister. She is at the very low end of the healthy weight range now. I'm so glad I have time off over Christmas to make sure she eats something.
Does anyone have any advice? I just feel like crying to see her like this.

Don't tell her how much you dislike the friend, you'll just get your DD's back up. There's no one right way but I would be thinking about trying some of these things:

Does she know that her weight is at the low end of healthy (what is her BMI?), what does she say about that or the fact you're concerned about it. What is her plan to make sure she stays a healthy weight, give her faith that you believe she can take care of this, but you want to hear what her plan is. You can talk about this in a joking Mama way, us mums want to see our kids eat(!). Main thing is, people with EDs want to hide them and fool themselves they are doing a good job hiding. Make it clear, she's hiding nothing. You see full well.

Is she feeling out of control in other parts of her life (most teens have moments like that). You can ask what is bothering her and what can you do to help her feel less overwhelmed. She's the boss, you're the support.

Apart from the friend you dislike, does she have friends she talks to, share her problems with?

If she talk to someone (maybe her twin) about the friend she falls out with, listen to her, encourage her to talk thru her feelings. The more she talks thru her feelings & feels listened to, the better the chance she'll realise that she's a worthwhile person who deserves better than a volatile unsupportive friendship.

Thank you so much lljkk I am going to work on some of what you have suggested