Ana Carolina Reston, a successful fashion model, succumbed to anorexia in November 2006 after a prolonged diet of apples and tomatoes. The 21-year-old from Brazil weighed just six stone at the time of her death.

Luisel Ramos, a model from Uruguay, suffered a heart attack minutes after coming off the catwalk in August 2006. Told that she could make it big in the fashion industry if she lost some weight, the 22-year-old had lived exclusively on lettuce and diet coke for three months.

For an industry long inured to images of ultra-skinny models, the double deaths were a shocking wake-up call. From Rome to Madrid, fashion heads demanded an immediate ban on 'size zero' models. Top designers admitted that things had got out of hand. An industry commission was dispatched to examine the health of fashion models.

All of a sudden, just like last season's collections, skinny was out. For the 2008 fall and winter collections, big-boned was in.

But as New York fashion week wraps up today, and London prepares to launch its Spring 2009 collections on Sunday, the ultra-thin model has made her comeback.

Spurred on by a spike in reality TV shows promoting extreme dieting, women are once again being encouraged to jettison the pounds and emulate the waif-like proportions of Kate Moss and Victoria Beckham.

MTV has come under sharp criticism for plans to air a new reality show, Model Maker, which encourages aspiring models to lose between two and five stone in a vigorous dieting "boot camp" in the hopes of becoming the next 'size zero' supermodel.

"Women come in all shapes and sizes, but models don't," says the MTV statement. "Skinny, no body fat and size zero are the words and phrases associated with models. Chubby, well-fed and big-boned are not."

An American size zero is equivalent to an Irish size four and fits a 22-inch waist -- the average measurement of an eight-year-old girl.

But a renowned eating disorders expert says that the media's fascination with stick-thin celebrities and the promotion of extreme dieting can lead to dangerous eating habits and potentially fatal illnesses such as anorexia nervosa.

"This is a life-threatening illness. It is highly pathological," said Dr Kathryn Zerbe, a psychiatrist at the Oregon Health and Science University and author of Integrated Treatment of Eating Disorders: Beyond the Body Betrayed.

"As people look at thin models they want to take on that body [image]. But the bottom line is that the models, in risking their own lives by doing this, are through identification encouraging the young girls and other young women to want to do the same."

In her private practice, Zerbe counsels women suffering from eating disorders who are working in the entertainment industry and under extreme pressure to lose weight and maintain that 'picture perfect' image on television.

"I have a number of actresses in my practice who come up from LA or who I've consulted with on the phone ... and they're being constantly told by their directors to lose weight, that they're too heavy," she said.

As London prepares to court the fashion world this weekend, an initiative to have models produce health certificates ensuring a healthy body mass index above 18.5 was abandoned after other fashion capitals refused to get in on the act.

At the time of her death, Ana Carolina Reston had a body mass index of 12.5 -- two and a half stone below the recommended minimum weight for her height.

"From our conversations with our international counterparts in New York, Milan and Paris it has become clear that they do not recognise the need for an international health certificate," said Hilary Riva of the British Fashion Council (BFC).

Reportedly concerned that some sought-after fashion models might go elsewhere if forced to pay up to £500 (€628) for the health certificate, the BFC said that other measures to improve models' health would be implemented.

These include banning models under the age of 16, providing healthy food backstage - chicken and avocado sandwiches and 'designer fuel' smoothies were the snack of choice at the runway show of well-known fashion house earlier this year -- and keeping drugs and alcohol away from runways.

A 'model sanctuary' -- a house where models can go to relax, eat or receive counsel from a variety of specialists -- was also being made available to stressed-out models for this coming London Fashion Week.

"I would love for there to be a simpler solution," said Riva. "If we could just tick a box and move on it would make everyone's life easier but now this really is a long-term behavioural and educational campaign."

But in the fight to enlighten an increasingly image obsessed public against the horrors of anorexia and bulimia, educators face a formidable foe in the guise of a celebrity and fashion-driven media.

"The media does play a role. Image plays a role," said Dr. Zerbe.

"The culture of narcissism plays a role where we all want to look a particular way."

Take Janice Dickinson, the self-proclaimed "world's first supermodel" and loud-mouthed star of the reality model show, The Janice Dickinson Modeling Agency, who has a very specific look in mind when scouting for potential talent.

"I'm dying to find kids who are too thin," Dickinson told a reporter last year.

"I've got 42 models in my agency and I'm trying to get them to lose weight. In fact, I wish they'd come down with some anorexia.

"I'm not kidding. I'm running into a bunch of fat-assed, lazy little bitches who don't know how to do the stairs or get their butts into the gym."

For the millions of young Americans who tune in weekly to watch her show, Dickinson has a message.

"Models are supposed to be thin. They're not supposed to eat," she said.

- Caitriona Palmer