Is There an Ideal Female Body? What the Science Really Says

Originally published 2018-05-09.

The Claim That Science Has Identified an Ideal Female Body

Every few years a headline announces that scientists have measured the "perfect" female body. One version that spread widely online said researchers at the University of Texas had settled on a height of 1.68 metres and measurements of 99-63-91 centimetres, and named the English model and actress Kelly Brook as the real-life example.

Here is the honest answer up front: no single study defines an ideal body, and the specific Texas study behind the viral numbers has never been clearly identified. What the claim does echo is a real and much-debated line of research on waist-to-hip ratio, which began with work at the University of Texas in the 1990s. That research says something about average preferences in particular samples. It says nothing about what any woman should look like, or about her health or worth.

Where the "perfect measurements" story comes from

Convert the viral figures and you get roughly 5 feet 6 inches tall, with a 39-inch bust, a waist of about 25 inches and hips of about 36 inches. The detail that matters to researchers is the ratio between the last two numbers: 63 divided by 91 is about 0.7.

That figure is familiar. In 1993 the psychologist Devendra Singh, then at the University of Texas at Austin, published studies in which men rated line drawings of female figures. Across his samples, normal-weight figures with a low ratio, around a waist about 70 percent the width of the hips, tended to be rated most attractive, while very thin figures were rated less favourably. Later researchers repeated versions of the experiment, and Singh's work became the most cited source for the idea of an "ideal" 0.7 ratio.

So the viral post is probably a mash-up: a real research finding about proportion, attached to an invented set of exact measurements and a celebrity photo. Treat the precise numbers as internet folklore rather than a scientific result.

Who Kelly Brook is, and why she became the example

Kelly Brook was born in Kent, England, in 1979. She started modelling at 16 after winning a beauty contest, presented youth television and The Big Breakfast, and acted in films including The Italian Job (2003) and Piranha 3D (2010). Her modelling success came mainly from glamour, swimwear and lingerie work rather than the catwalk, and she has spoken openly over the years about pressure over her weight and figure.

That made her an appealing face for the headline: a curvy woman outside the catwalk mould, now crowned by "science". It is a satisfying narrative, but it was editors and bloggers, not researchers, who picked her. Plenty of women with very different shapes have similar waist-to-hip ratios.

What attraction research actually says

Evolutionary psychologists have argued that some preferences may have deep roots. The usual theory is that features linked to youth and good health, including clear skin, facial symmetry and a lower waist-to-hip ratio, might once have hinted at fertility, so people who were drawn to them may have left more descendants. Researchers have linked waist-to-hip ratio with hormone levels and some health measures, which is why the idea took hold.

There is also evidence that some judgements overlap between cultures. In 1994 The New York Times reported on research suggesting that people from different backgrounds often agree about which faces are attractive. In 2012 Live Science reported a study led by David Puts of Pennsylvania State University in which men rated women's faces and voices as more attractive at hormonal points of the cycle linked with higher fertility.

But the evidence is far messier than "men prefer this one shape". Some important complications:

Body size preferences vary a lot. Studies comparing countries and communities find that where food is scarce, heavier figures are often preferred, while richer urban samples tend to favour slimmer ones. Ideals also shift over decades, as the history of fashion and art shows.
The lab is not real life. Rating drawings or photos on a screen is very different from how people actually choose partners, where personality, humour, kindness and shared values carry great weight.
Samples are narrow. Much of the early work used university students in Western countries, and many studies measured only men's preferences for women.
Averages hide individuals. Even when a study finds a preferred ratio, plenty of participants prefer something else.

Why runway models look so different

If curvier figures do so well in these studies, why are fashion models usually very slim and tall? The common explanation from people inside the industry is practical rather than romantic. In one widely shared answer on Quora, a writer who said they had worked for designer Karl Lagerfeld, Chanel's long-time creative director who died in 2019, explained that models are chosen to show off the cut and drape of the clothes, and a very slender frame works like a moving hanger.

Sample sizes, the cost of producing a single garment for a show, and the tradition that collections are judged on how fabric falls all reinforce that habit. In other words, runway casting is a design decision, not a statement about what the public finds beautiful. That is also why the bodies seen in swimwear, lingerie and fitness advertising often look quite different from those on the catwalk.

Attractiveness is not the same as health

It is tempting to treat "attractive" and "healthy" as the same thing, but they are separate questions. Being very underweight can bring real problems, such as weakened bones, anaemia, fertility problems and lowered immunity. Carrying a lot of fat around the waist is linked with higher risks of type 2 diabetes and heart disease. That is why the World Health Organization lists waist circumference and waist-to-hip ratio as useful health markers alongside body mass index.

None of these markers is a beauty score. Two women with the same ratio can have very different levels of fitness, and many healthy bodies look nothing like a model's. If you are worried about your weight or shape, the useful step is to talk to a doctor, who can look at your whole health rather than a single number.

Myths worth dropping

"Science has proved there is one perfect body." It has not. Research describes average preferences in specific groups at specific times.

"If you do not match the measurements, you are less attractive." Attraction is personal and depends on far more than proportions.

"Thin models represent what men want." Catwalk casting is driven by how clothes are displayed, not by attraction surveys.

"A curvy celebrity being named 'ideal' makes curves the new rule." Swapping one narrow ideal for another does little to help anyone. The healthier message from the research is that bodies, and the people who admire them, come in a wide range.

Watch: female body ideals through history

The short video below looks at how ideas of the "ideal" female body have changed over the centuries, which is a good reminder of how much these standards depend on time and place.