Why on earth is this such a 'shocker?'
Many teenagers/young women feel like this now, and felt like this then.
I was 9 st 4 at 5 ft 4 when I was 18 or so, (1980s) and had a 26 inch waist. I went on a 'crash-diet' to try and lose 10 pounds, because I felt and (thought) I looked fat. I ate 3 apples in one week. (This is in MY diary from then.) 3 fecking apples! I put in my diary some days that I had been GOOD today, because I had had nothing to eat.
Seems horrific now, but I did this, and so did others. (Some probably do now.) I had a 24 inch waist a couple of months later at 19 now, (after losing nearly a stone and dropping to 8 stone 7.) About 3 months after I had dropped to 8 stone 7, a bloke I had just started to see squeezed my waist on the dance floor and said 'you can pinch more than an inch haha.' (Of fat he meant!)
I had finished my diet 3 months earlier, but this threw me right back into crash dieting again. I dropped to 7 stone 12, and had a 22 inch waist. I looked like a fucking corpse, grey in the face, and worn out, and my mum nearly cried saying, FGS Zov, EAT! I thought I looked great, (I saw how awful I looked when I looked back at photos from then a few years later...) I also exercised feverishly, and ran and cycled and danced and burned off LOADS of calories. Also walked almost everywhere.
People were obsessed with being thin in the 1980s, and the 1970s were no different. There were diet aids all over the place. Aydslim, Slimfast, weightwatchers, aerobics, F-plan, Cambridge diet, Mayo Clinic Diet etc etc etc.... Wanting to be thin is not new. Even before then women strived to be thin/slim. My aunt (born in the 1930s) said she drank a whole bottle of castor oil to try to lose weight when she was about 17 - in the 1950s!
(It's not being 7 stone 12 that made me look so awful, it was the crash dieting, not eating hardly anything, and losing weight fast that did it. I'm not saying anyone at that weight will look like shite!)
I was also extremely flattered when I had men chatting me up and I got wolf whistled. (I know I know!) It started getting on my nerves by the time I was in my early-mid 20s, especially when I got hit on, said no, and got abused by the man in question!
But yeah tl;dr, I don't think this 1975 diary is shocking @NorthernGirl1975 Most women have always strived to be attractive, to be thin, and to look good (often to attract men!)