Thanks for your comment. From what I understand, Paleolithic women had such a low level of body fat that they only menstruated 4 times per year. It seems unlikely then that they would have much in the way of hips, and were probably more likely built like the Egyptian ideal in the link I posted, which is more like a 1920s flapper body.
The study I cited also said that the hour-glass figures that are considered attractive are less likely to indicate fertility because they are more likely to be on teenaged bodies and women’s fertility peaks in their 20s.
Men tend to prefer women with very low waist-to-hip ratios (whose waists are much narrower than their hips), but these women are actually less likely to conceive than women with a less pronounced hourglass figure. (emphasis mine) Younger women are more likely to have an hourglass figure, and age is related to fertility, but the most attractive waist-to-hip ratios are generally found in women in their late teens, whereas women’s fertility tends to peak in their mid to late twenties.