What can we as grandparents do?

I agree that it sounds like an eating disorder, and you should also watch out for her wearing baggy clothes, exercising excessively, etc. However, it is possible that your first guess was right and that it is actually a tummy problem.

Conditions such as IBS can be exacerbated by stress and it certainly sounds as if she has a lot of stress in her life. There are also conditions such as Crohns or Ulcerative Colitis which often begin when people are young - I speak from experience regarding the latter. Is she complaining of tummy pain? They're auto-immune conditions but they too can be made worse by stress.

Whatever the problem is, a visit to the GP is the best place to start.

That sounds a sensible approach. Years ago I had a teenage relative with similar behaviour which was concerning. They have recently been diagnosed as coeliac and have to avoid gluten.

Stay out of it ... it is a very difficult thing to advise anyone about it ..let the parents handle it ...

The sooner the young lady gets appropriate help, the sooner she may recover.

CountessFosco

Thank you all sincerely for your wise advice and comments. Without wishing to be too forthcoming, we feel it is bulimia. The two girls are off on holiday today with their Dad alone. Perhaps that will bring some stability? If not, we shall speak with him when they return.

A holiday might be just what they all need. I hope it gets resolved favourably for all concerned.

You pass on direct facts to Dad without speculation because there are also lots of health conditions that can cause this too. "We have noticed X and wanted to let you know so you can keep an eye on it".

Whilst you cannot do a great deal about the situation she finds herself in, just being the granny and grandad that she has always known. Slowly the stability and familiar conditions you provide will help her to get through this time. Dont try and do extra and unusual things, but the normal routine and the usual food that you make will be very comforting, because it is the same as always. Mentally, having the familiar things will reassure her that not everything is changing and that you will be a safe place for her when she needs it. I would look back and think what you might have done with her over the last couple of years and do that. So perhaps you used to go swimming and have a picnic. She may say that she doesnt want to do that now, but knowing that not everything is changing and that she can still go back to a happier place could be comforting.

V3ra

That behaviour suggests bulimia to me 😕

This is what I think and it is all about control. She cannot control her parents relationship, but she can control what she eats and gets rid off. Bulimia can be life threatening, I know only too well having had a GD with an eating disorder, not Bulimia, but all the same an eating disorder.
You need to speak with you son about your concern.

Sounds like bulemia. Often a response in young people to stressful unmanageable situations that they have no control over.
I think I would tell her parents who sound caught up in their own difficulties.

The girl is sixteen, do why do you not ask her what is wrong?

Nicely, saying you have noticed she suddenly has to rush to the toilet after meals, so you are wondering whether she is allergic to something you use in cooking, stressed about her parents, or is she worried about something.

Her parents have so many worries they may not have noticed, particularly if she is hiding it well. Happened to friends of ours and fortunately her lovely best friend raised the alarm with a teacher. Don’t delay taking action, raise it with DS so he can watch her discreetly on holiday. Hopefully it’s a given that he will raise concerns with her mother.

Tenko

OP ,this sounds like an eating disorder and the situation is classic , stress of exams , patents divorcing , moving home and possibly school. It’s her way of gaining some control over the situation.
Find a time to talk to her about your concerns . And talk to her parents. They maybe so wrapped in their concerns, they haven’t noticed .
Just a thought about her clothes . It’s summer , is she wearing baggy clothes or joggers , hiding any weight loss.
Despite any acrimony with the DIL , your dgd comes first .

I agree with Tenko.

It could have been primarily anxiety about her exams but with her parents splitting up on top of the stress of that, it is probably too much for the girl to cope with.
She is trying to exert some control over her life.

Another thought is whether she is accessing websites online? Some of them are quite sinister, encouraging youngsters to self-harm.
I think you should see what the situation is like when they return from holiday and perhaps raise your concerns with your son if she is still doing the same.

This website could be of help:
www.beateatingdisorders.org.uk/get-information-and-support/get-help-for-myself/i-need-support-now/helplines/

There may be others.

You can report this to social services..she has builimia where she makes herself after eating ....you could also raise concerns s with her school.dobt let this ride .she needs help

Why on earth should CountessFosco report this to Social Services?

Oh golly, we had many years of battling bulimia with our gorgeous, talented, ADHD daughter. Don't give up, but he prepared for the long haul. I'm a psychologist but it took a doctor from outside to help her learn how to recover. Sending your family love. BTW she has a wonderful husband and two amazing children now, one of whom is also ADHD but absolutely magnificent 🥰