I don't have any data on weight or body fat, but there's plenty of research into attractiveness of women with various waist-hip ratios and yes, it has dropped steadily from around 0.77 in 1500 to 0.68 in the last half-century. However, does even a WHR of 0.77 correspond to being fat?

Source: http://journals.plos.org/plosone/article?id=10.1371/journal....