It turns out men do prefer curves, but usually for casual relationships

Researchers discovered men determine whether a woman is a potential short-term physical partner or a long-term mate simply by examining her features. A research team interviewed 375 men and women and concluded that men categorize women with attractive, curvy bodies as short-term partners, whereas a woman with a pretty face would more likely be considered for a long-term relationship. While men favored an attractive face specifically in long-term relationships, women preferred attractive faces in both cases. Women made judgments based on the face 69% of the time for both short- and long-term relationships in the study, but men based their choice on the face 75% of the time only for long-term mates. Some indication as to why a woman’s body is more appealing to men for physical relations has to do with her body’s indication of fertility. Studies show that a woman’s waist-to-hip ratio is a cue to her current fertility levels, so a higher waist-to-hip ratio would mean higher fertility rates. Cues that are associated with high fertility are not a conscious mechanism. It is a subconscious method of attraction.