Very interesting thread this. I was blessed with a pretty ideal figure when I was younger, despite eating whatever the hell I liked - big breasts, small waist, not so keen on the legs but could cover those up, hip bones just visible in a flat belly...
However, at that period in my life, I'd pretty much internalised that that's all I had to offer. I honestly considered myself to be pretty stupid, and I've always struggled with depression so I was convinced of my defective personality. So I maximised what I thought were my only assets, and dressed to display them to maximum effect. Low cut and tight goes down pretty well with men, but doesn't tend to go down well with other women - if you want their approval I think you're supposed to follow fashion and be constantly told what you should be wearing. 'Read this magazine! Are you in this season's colours?! Spend hundreds of ££ on this dress, and thousands on this bag that I wouldn't buy for a fiver in a charity shop ! Maxi dresses don't suit you? Who cares? You must wear them anyway! Can't afford to be fashionable? But you must - just put it on the credit card!'
You can tell I'm not a follower of fashion.
It took me years though, to realise that I had more to offer than big tits and a small waist. Luckily that happened in time to comfort me as those big tits head south and the hip bones have disappeared under a layer of doughiness. Now I watch what I'm eating when my size 12 trousers get too tight, and I dress to flatter my shape with what I know suits me. I think that the pressure to be thin and well dressed does come predominantly from other women, but results from a centuries old internalised belief that our use in life is often decorative - be pretty and feminine, don't make noise or fuss, do as you're told and let the men get on with the important stuff.
Also, as society gets fatter, the elite get thinner. It's a way of differentiating yourself from the proles, isn't it. In cultures where food is scarce, to be large is to be beautiful, as it's a sign of prosperity and power. But we have an excess of cheap shit junk food available, so the western world is getting fatter. Therefore the people at the top of the food chain, so to speak, show their power by being very thin.