Revealed: The actual reason catwalk models are so thin.

The skinny model outcry is now an annual event. It coincides with fashion week. Every year, it’s been there. It’s an eye-roll because it’s so predictable. Every year thin models, every year angry backlash.

Which leads to the question – every year – why hasn’t it changed? If the outcry, like the event itself, is annual, why doesn’t the fashion industry stop casting waifs?

It’s baffling to outsiders, but I know the answer.

First, let it be said that some waifs are thinner than others. And some waifs wind up in hospital, and this is never, ever okay.

So, why did Alex Perry tell Today this year that his sample has gone from a ten, to an eight, to barely a six in the past few years?

The answer to that question is local. Cut off from the rest of the world, still in its relative infancy, crushed by a soaring dollar and lack of manufacturing savoir faire and pressured by the arrival of international brands, the Australian fashion industry is incredibly insecure and therefore, conservative.

Australian fashion people are painfully aware that we live in the provinces. The boonies even. Because of our geographical and economic insecurity, we do what all awkward fledglings do. We copy what the coolest, oldest most established players are doing, in order to fit in.  In fashion, that would be Paris. Having girls who walked in a lot of shows overseas is a huge sign of prestige for an Australian designer.

Since fashion week moved from May to April, many of the models cast at Australian Fashion Week shows come straight off the runways at Paris. They’ve just completed a grueling month of international fashion weeks, flying from New York to London to Milan to Paris.

The Fashion Month circuit is brutal. If you’re working a lot, it means you’re working six to seven day weeks, for eight to sixteen hours a day. For a month. There’s rarely food backstage. Most models will scarf whatever they can get their hands on once a day, between shows or late at night. For a month. Not because they want to, but because that’s the reality of the job.

It’s not unusual for a model to start fashion month model-thin, and end fashion month frighteningly thin. Australia gets our models back once Paris is finished with them.

Using a girl who didn’t walk at Paris in your show? Not very sophisticated. Except when it is. Bianca Spender’s show on Wednesday evening featured many models who haven’t done the international runway circuit in several years, and looked so much the better for it. Her models were still a sample size, but it was a sane sample size. She is more established in Australia than most. She can take that risk, use her clout to cast models who are self possessed, stunning, grown-ass women like Tanja Gacic, without fear the model might steal light from her clothes.

For others, casting fresh-from-Paris mannequins feels like a safer bet.

So why does Paris demand girls to be model-thin in the first place? This is a little more complicated than Australia’s act of keeping up with Le Joneses.

The thing you have to remember about high fashion is that it isn’t really for you. H&M is for you. Country Road is for you. And if your really feel like splurging, Sass and Bide is for you. But it is unlikely that you will ever buy a $5,000 dress from Chanel.

But there are people who can. And high fashion is for them.  Ever since the anorexic Empress Elisabeth of Austria became a style icon  – 18 inch waist and all – in the 1860s, being painfully thin has been seen as just about the poshest thing you can do.

As calories became cheaper and the poorest in society grew bigger, the relationship between wealth and extreme slenderness has only deepened. This isn’t new. Look at Coco ‘elegance is refusal’ Chanel; Audrey Hepburn; Posh Spice (aka Skinny Spice) and post-wedding pre-pregnancy Duchess Catherine.  All of them, if you put them in a frock that looked like the one Cassi Van Den Dungen wore at Alex Perry’s show, would have been almost the same size as her.

In fashion, you can still never be too rich or too thin.

But Audrey and Duchess Catherine can’t be as thin as Cassi, right? They never looked scary in the way that she did.  Of course they didn’t. But it’s because they dressed differently. They wear skirts that cover their legs. There’s a reason it’s still a bit gauche to show upper thigh. Thick or thin, upper thigh is still shocking.

Go and watch Sabrina, really pay attention to Audrey Hepburn’s body, then tell me whether or not she looks healthy (she doesn’t). She does however look amazing in her dresses.  This is the other reason fashion adores extreme thinness. With certain dresses and certain proportions, especially the ones that require loads and loads of fabric –  like the ‘new pretty’ midi skirts and cocoon shaped blouses that are trending at the moment –  super skinny looks better.

This is because extreme thinness makes one into a literal clothes hanger. Bodies are distracting things, especially women’s bodies. They’re much more interesting to look at than clothes. The curve of a breast, the heft of a thigh. These are things we’re hardwired to like. Alessandro Ambrosio’s thighs were the most noticeable thing about her in the pictures that were posted to contrast her with Cassie after Alex Perry’s show. And so they should be.

Extreme thinness done right neutralizes the distraction of the female body. The wearer is so tiny they literally cease to exist, and the garment becomes the dominant story. The reason women who are especially celebrated as stylish rather than sexy tend to be extremely slender is because their bodies are less ‘distracting’, so their clothes can shine.

Because thin bodies highlight clothes better, and because we associate thinness with wealth, thin girls have the affect of making cheaper clothes look more expensive. Or so designers believe. A dress doesn’t have to be especially well cut or well made or well designed to look ‘right’ on a very thin girl.

As a designer, in order to flatter a more realistic shape, you have to have something very special and very specific: talent.