I'd say that the attraction to curves back in the day had more to do with the
appearance of both wealth and health than it does more hardwired evolutionary impulses. If anything, it is men that must compete to win a mate, not the other way around, so if one is to appeal to evolutionary psychology, the question would be what women want, not us.
Sadly, even after 200,000 years on this planet, our best and brightest have yet to decipher what women want.