Not particularly, I used to wear her old clothes when I was 15 and about 8 and a half stone (or in her words 'was absolutely huge'). The few photos that existed of her were of somebody who looked ordinary and, according to her, it wasn't as though she was five stone something like a 'proper slim person', she was 'just naturally little, I just can't eat loads like you, don't forget I'm only size 4 in shoes and my hands are tiny'.
What she did do to maintain her identity was avoid all fat - which included all full fat dairy, all oily fish, beef, lamb, dressings, sauces and if there was a way to water something down, she'd do it if she couldn't ensure it never entered the house in the first place. So it was the cutting out practically all sources of calcium and vitamin D with the intention of remaining the same size she was at 17 that knackered her bones in such a short time.
But at the time, you were recommended to have a low fat diet, so on paper, she appeared to eat fairly well with meals consisting of lean chicken or ham, boiled vegetables, lettuce, salad and the occasional slice of toast and potatoes on Sundays. It was a further flex (in her opinion) that we didn't have fruit either. Full of sugar, those things, and the bag of Tate and Lyle that turned into a solid lump over about a decade in the cupboard was proof of how virtuous she was.
She was always very eager to share her opinions about other women and children's sizes, though - and those opinions had a lot in common with modern narratives of 'gorging' and 'constantly eating' and 'people can't remember what children looked like 20 years ago'.