Teen daughter eating in secret - AIBU to tell her I know?

[Secreteatinghelp]

I'd love some advice. DD (15) has been referred to an endocrinologist for hormonal (period related) issues. At our first appointment the endo gently expressed concern about DD's weight. She is 5'3" and *75kg, has always carried extra but has gained significantly in the last six months or so. She has stopped growing height wise (we know this as she's had an xray to investigate as part of the investigation into her hormonal situation.)

During the appointment we discussed DD's diet. We eat very healthily at home, she takes healthy lunches to school, and she exercises regularly, although mostly weights rather than cardio. We have all therefore been at a loss to understand her weight gain, which to be clear is a concern for me from a health POV only.

I discovered last night that DD has been eating extra meals before coming home and having dinner. Her banking app is on my phone (it's actually my second current account that she uses for her pocket / bday money / Saturday job money). It was showing a notification last night and so I opened it, which I don't normally do. There on the main screen is a string of payments - once or twice a week - to local takeaways. There are also lots of payments to local supermarkets and convenience shops. For example there's £15 to the local fish and chip place.

I find this whole area so hard to talk to her about. We have a very close relationship and she knows I think she's wonderful and beautiful. We only very rarely talk about her diet and then it's only from a health pov.

I feel like I have to tell DD I've seen the payments in the app and try to talk to her about it, but I'd really appreciate any advice on how to approach. We're due to see the endo in a few weeks and I think we need to give her the whole picture.

I'm feeling really conflicted about whether to say anything at all, hence the AIBU. I'm scared of pushing her into being even more secretive.

MNHQ at OP's request corrected typo 175kg to 75kg

True and thinking about it even if it was full fish and chips I think its 12 quid not 15 round here

The problem is a lot of people would see a battered sausage and some chips as a snack, she wouldnt necessarilly view that as 'well Ive had my tea so wont have anything at home'

Maybe it's too late but please, please if not, don't tell her you looked at her phone. So much unbelievable damage has been done by people feeling betrayed by someone looking at their phone, particularly if it's a loved one. Obviously the endocr needs the full picture but rather than you bring it up in front of your daughter, see the doctor separately and explain. If she has a real eating disorder, that means there is some trauma or stress involved and the last thing you want to do is add to that.

As some one who experienced all kinds of eating disorders and disordered eating in my twenties and thirties, I think just approaching it kindly and perhaps getting a therapist involved might help? Perhaps she's not feeling satisfied with the meals she has or perhaps she feels shame around junk food. Hope you manage to sort it out. It's really best to nip these issues in the bud when people are young.