Peter Katzmarzyk and Caroline Davis of York University in Ontario, Canada, analysed the weights and measures of the 240 women who appeared as Playboy centrefolds between 1978 and 1998. Average BMI was 18.1 kilograms per square metre. Current recommendations classify anything under 18.5 as underweight. Perhaps surprisingly, the researchers found that both BMI and WHR changed little over the two decades. Previous studies found that Playboy models became less curvy between 1950 and 1980, compared with the average population.
Anecdotal evidence suggests that models appearing in adverts aimed at women are getting thinner.
But it may not be that simple, says Andy Hill, a psychologist who studies body shape, obesity and eating disorders at Leeds University in the United Kingdom. It doesn't surprise me at all that they haven't found much change in BMI over 20 years. It's not just a case of models getting skinnier, but also that the numbers of overweight and obese people have gone through the roof in recent years. So the disparity between ideal body shape and reality is growing and that's what brings damaging consequences for health. Nine in ten women, he adds, will never achieve their perfect shape.