It's really easy to be close to a situation so you're unable to think of solutions when if a friend was asking you, you'd be able to think!
Emotions can freeze brains sometimes.
My mum has done similar for me as has my closest friend, but I've done similar for them (I hope!)
And really that's what we hope for from mn when we're struggling with issues like this isn't it?
When dd was first diagnosed and one of the main pieces of advice re the eating issues was that she's best eating 6 small meals a day than 3 "squares" I was completely thrown initially! My friend was able to "talk me down" as she cares for her elderly dad and he has some stomach issues and can't manage large meals and she was able to advise me to "break it down" and remember I didn't have to try and squeeze all the food groups into every meal I could have dairy and carbs in one meal and veg and protein in another etc as long as over the day she was getting enough cals and nutrition. Getting enough cals into dd is REALLY hard because she tends to the low cal in preference but has a high metabolism. Milk based drinks help a lot with that!
ALL that said my diet as a 14 year old was horrific when it was up to me! I DID like Chips, and chocolate, and ice cream, and crisps... I was also extremely slim at that time so my parents weren't so much concerned with that side but they did worry about the lack of nourishment, dad would be like "get some fruit" soon as I got in the door with a bag of chips in hand and mum really upped the veg and protein in our evening meals.
Bro was shooting up around the same time as I recall (he's a 6.5 foot block of cop these days!) and was eating them out of house and home! Just seemingly unfillable!
Teens especially boys (not because of gender roles but physiology) need more cals than not only younger dc but most adults too.
I have a "treasured" family photo my sister took of me as a size 4 tiny 15 year old in a swimsuit at local beach scoffing an "extra" size marathon! She just thought the contradiction was hilarious. 