Crystal spent the majority of her early modelling career striving to make it as a 'straight-size' (as in, size zero thin) model, developing the eating disorder anorexia nervosa as a result. In an interview with German publication Spiegel she admitted:
"I was asking how many calories chewing gum had and I spent eight hours in the gym every day. At 5 feet 7 inches I ended up weighting 108 pounds (49 kilos). It was a constant agony. My hair fell out and I was isolating myself more and more."
In an interview with Time, Renn describes taking the decision to deal with the disorder:
"I remember having my epiphany moment and making the decision to eat again. It was pretty amazing. My first meal was what many would regard as very healthy: a salad with salmon, walnuts and olive oil. At the time, I feared that I would gain 100 lb. with one bite. It didn't happen, and I felt superrelieved. I knew I was on the right path."
She then went on to add:
"I don't really watch my weight at all now. I do make sure that I eat as healthy as I can for energy purposes, but I no longer restrict my calorie intake to feel better about myself."
It was hugely refreshing to have this articulate, healthy, engaging woman flying the flag for normal-sized women in the fashion industry as well as strutting down the runway for Jean Paul Gaultier.
Over the last year we've caught sight of Renn at various weights between super skinny and plus-size but her red carpet appearance for the opening night of the Metropolitan Opera Season 2011 seemed to signify a different outlook.
In February, Renn told the Ford Models Blog:
"I couldn't possibly live up to [the plus-size image people had of me], and at this point in my life I would have to actually have another eating disorder to live up to that expectation. I had anorexia ultimately because someone else set the standard for me and I wanted to follow it. And if I followed what the public wanted from me or what the media wants from me, I'd be doing the same thing... [I]t's about individual health. You cannot tell if someone is healthy, where they are mentally, from the outside, because health is different for everybody at different sizes."
To compare Renn's Mark Fast appearance with the models from his recent NYFW show, click through the gallery below: