Researchers looked at trends in Playboy centrefold models' body measurements by analysing 577 consecutive monthly issues of Playboy, from the magazine's inception in December 1953 to December 2001. They extracted centrefolds' anthropometric data: height, weight, and measurements for bust, waist, and hip.
From these data, they calculated body mass index, waist:hip ratio, waist:bust ratio, and an androgyny index.
All measures except weight showed significant temporal change. Over time, bust size and hip size decreased, while waist size increased. Measures of body shape followed the same trends: body mass index and bust:hip ratio decreased, while waist:hip ratio, waist:bust ratio, and androgyny index increased.
These findings suggest notable temporal trends in measures of body shape in Playboy centrefold models, say the authors. The typical body mass index of Playboy centrefolds has further descended below corresponding population levels, whereas their typical waist:hip ratio now approaches population levels.
These temporal trends are at odds with claims that centrefolds' body shapes are still more "hourglass" than "stick insects" and that the maximally sexually attractive female waist:hip ratio is stable, they conclude.