Funny you should say this ... back in the late 1980s, when I was in my early 20s, I was a size 12 (probably size 8 to 10 these days,) and roughly 9 stone 5. (And I'm 5 foot 4.)
I worked with three girls/young women in my office, all a similar age. They were an inch to two inches shorter than me, and they were 7 and a half to 8 stone, and a size 8 to 10. (Now they would be a 4 to 6!) They had 21 and 22 inch waists. Mine was 25.
I was classed by them - and a couple of lads in the office as the fat one. I shit you not. Now being 9 stone 5, at 5 foot 4 is classed as slim. It's not that we've lost sight of what slim or healthy is, it's just that some 30+ years ago, people were a lot slimmer/a lot thinner.
Just go look at an episode of Friends from the mid 1990s now and have a look at how thin Courteney Cox was then. She was actually stick-thin, and yet at the time, she didn't look particularly stick-thin, she just looked slim.
People are a bit bigger now, and girls are curvier, but it's not a bad thing. The human race is evolving and people are just a little bit bigger. Not fat, obese, or gross. And we need to get off this mindset that everybody is fucking fat now!