Captivated by Bundchen's intimidating beauty and poise, the high-school girl from Mississippi stared at the photo in awe. "This could be you," said a voice next to her.

That voice belonged to a New York modelling scout, who had stopped off in Renn's tiny town in the search for America's next supermodel.

He was right. In less than a decade, Crystal Renn (23) has become one of the world's most sought-after and successful fashion models, her face gracing the covers of Harper's Bazaar and Elle magazines.

But there's a catch.

In an industry ruled by hungry-looking waifs, 5ft 9in Renn weighs a healthy 12 stone and wears a British size 14-16. Big and beautiful, Renn has found international fame as America's most successful plus-size model, becoming only one of a handful of curvy women to break the barriers of high fashion.

Along the way, she is challenging how the weight-obsessed fashion industry views full-figured women and railing against the intolerable pressure placed on young models to remain at a skeletal-looking -- but economically viable -- size two (British size 6).

Renn understands these pressures. As a 14-year-old, she started to starve herself to near death in a misguided attempt to fulfil the fashion scout's prophecy and become the next Gisele.

In her compelling new memoir Hungry, Renn recounts how her anorexic spiral began the day the modelling scout picked her out from her etiquette class and told her that she was destined to be a supermodel.

"There's just one thing," he added. "You'd have to lose a bit of weight."

Renn went home and made some measurements. She was 5ft 9in and weighed nearly 12 stone. The scout had told her she'd need a 34in hip. She measured 43.

The very next day, she joined a gym and made dieting her full-time job. She lost 28 pounds in three months, but at 10 stone she remained over three stone more than the magical number that would deliver a 34in hip.

She ramped up her diet, implementing a more drastic meal plan of undressed lettuce, sugar-free gum and Diet Coke. She spent hours on the treadmill and in the pool. As her weight plummeted, her periods stopped and she began to have panic attacks. Deprived of energy, she fell asleep in class.

But the hard work 'paid off'. Nearly two years after she started dieting, Renn stepped on the scales one day and saw that she weighed just six-and-a-half stone. She'd lost more than 42pc of her body weight. She was finally perfect model material.

She immediately quit school, flew to New York and signed a modelling contract for $250,000. At just 16 years of age, she moved into a sparse apartment with other models, several of whom were also anorexic.

She joined two gyms so that she could flitter between the both without anyone realising she had an exercise addiction. On Sundays, she'd spend four hours in one and four in the other.

Her diet worsened. Terrified by the modelling competition surrounding her, she continued to starve herself, eating only steamed vegetables and lettuce. Her snack of choice was still sugar-free gum.

Her stomach growled and she became obsessed with thoughts of food. At night, Renn would sneak to the fridge, fill a spoon with peanut butter and cram it into her mouth. But then thoughts of the runway would appear and she'd spit it out and return to bed hungry.

Despite her skinny frame, her career refused to take off. She struggled to come across in pictures. Clients complained that she had a "weird personality".

"And I did," wrote Renn. "I had an eating disorder! Some days I radiated anxiety; other days when I was especially hungry, I reflected nothing.

"The stereotype of models is that we're brain-dead, but some of us are just starving," she said.

Renn obsessed over her emaciated body. She counted the blue veins protruding out of her long arms and panicked if one didn't stick out as much as she wanted it to. "If I couldn't grab my hip bone like the handle of a coffee mug, I panicked," she wrote.

She felt as if she was dying. Her hair fell out in clumps. She had a perpetual headache and heart palpitations. Her joints ached and her body temperature fluctuated wildly. She was constipated and in constant stomach pain. She couldn't sleep. At night, she would lie awake obsessing whether there were any calories in Diet Coke.

"I don't know what death feels like, but this had to be the beginning. I wanted to claw off my own face," she remembered.

Twenty-five years ago, according to Renn, the average female model weighed 8pc less than the average American woman. Nowadays, thanks in part to the 'heroin chic' look epitomised by Kate Moss in the early 90s, models weigh about 23pc less than the average woman.

But some fashion experts believe that the era of the super-skinny model may be drawing to a close.

There are now a few size six and 10 models on the runway -- although not many. This month, British knitwear designer Mark Fast dared to showcase his creations during London Fashion Week by using healthy-looking size 12 and 14 models.

In Italy in 2006 -- a month after the death of an anorexic Brazilian model -- the Italian fashion industry called for more fashion houses to add larger sizes to their collections and stipulated that runway models produce medical proof that they are not suffering from eating disorders.

For Renn, despite the constant dieting and the eight-hour weekend workouts, her body refused to remain at seven stone. In 2003, to her horror, she began to gain weight.

In a blind panic she increased her workouts and went on a cabbage soup and lemon juice diet, but still the weight continued to creep up on the scales.

When she hit nine stone, her modelling agency noticed and called her in. She was told she'd have to go on a diet. At that moment, in Renn's recollection, something snapped. She left the meeting and went straight to a café, where she ordered a salmon salad -- the first substantial meal she'd had in years.

The next day, Renn quit and a week later she signed with the Ford modelling agency to become a plus-size model.

She stopped counting calories and gave up her gym membership. Slowly, Renn began to regain the 70 pounds she had lost during her starvation, going from a US size 0 (or British size four, where a women's waist is the typical size of a seven-year old girl) to a size 12 (British 16). She gained a cleavage and her period came back.

Determined to break barriers as a full-figured model in high fashion, Renn refused to be cast as a catalogue model -- the usual bread and butter of plus-size modelling. She set her sights on Vogue and refused to back down. With her new sparkly personality and edgy looks, the work began to pour in. Her career began to sky-rocket.

She shot five international editions of Vogue, starred in a major Dolce & Gabbana ad campaign, walked the runway for Jean Paul Gaultier and became sought after by the world's most famous fashion photographers, such as Steven Meisel and Patrick Demarchelier. "She has an incredible body," said Meisel.

"I did better work as a plus-size model, not only because my brain was more fully engaged in the act of creation, but because I was more real," she said.

"You can be as beautiful as anything, but if you can't show people a little of your soul, you'll never make it. It wasn't until I became the weight I was meant to be that I figured that out."

Renn has said that she wrote her memoir to encourage women to embrace their own natural size and become their own person. "The solution is to accept that the only person you have to please is yourself," she said.

She rails against the tyranny of the fashion industry in perpetuating the notion that a super-skinny size four is considered 'normal' and that her healthy size 12 -- the size of the average American woman -- is deemed 'plus'.

She hopes that, one day, she can encourage teenage girls to look away from Kate Moss and Victoria Beckham and instead look to her as a role model for their body image.

"Women should be able to look to me and think, 'She's beautiful', but also, 'I can look like that'," she said.