I’ve been both, @Primrosecottagelover - 132kg and so skinny you could see my ribs (I’m in the middle now. I didn’t think I was posh, growing up, but can see now that where I grew up was affluent and I was surrounded by the Cheshire set who were the overwhelmingly slim, skinny jeans, Botox crew. My family on my mum’s side and their friends are mostly very slim - but it comes at a cost. They eat healthily but they don’t really snack, no takeouts, no ready meals, very little processed foods. Porridge or eggs for breakfast, maybe some soup or houmous/carrots for lunch, a protein-rich dinner with carbs, some healthy fats and plenty of veggies. Loads of fibre-rich foods throughout the day. Not a massive potato family. Desserts/sweet treats/crisps etc are for celebrations or when family/friends come over, fruit usually otherwise. No soda. Plenty of sleep, which limits energy crashes. Exercise six days out of seven, which limits cravings, even as it increases overall hunger (which is fine, as you just have slightly larger portions at mealtimes which your body needs). Eat when they’re hungry, stop when they’re full. It gives them disgustingly bouncy hair and clear skin, too 😒
I’m much the same again now, but I like the odd takeout and I love a dessert. I struggle with snacking when I’m on hormonal contraception (case in point: went on it again on 3 Jan, and in five weeks I put on 14kg and was miserable and ravenous all the time, but completely stopped the day I came off it - none of the women on my mum’s side have ever been on hormonal contraception and I think I understand why I started piling weight on when I went to uni, now, as it coincided with me going on the pill and I didn’t stop for another fourteen years).
I feel for you, though, OP! It’s really tough. I can hand on heart say that the ones I know aren’t starving themselves, though, they just make different choices. I choose not to make those same choices so I have cellulite and a buddha belly 😁. I think my belly is cute, though, like a grumpy, wobble face ☺️