Model Crystal Renn on Going from Size 0 to 12

She suffered from a crippling eating disorder to maintain the size 0 frame she needed to work in the fashion industry, but eventually found greater fame as a size 12 model. Now Crystal Renn is speaking out about the changes she thinks the fashion industry should make. 

"We, as a culture, are fixated, and perhaps even in an unhealthy way, with dress size and the scale size," Renn said in a new interview with ABC's 20/20, during which she debated the question, "Is it Okay to be Fat?" 

The model, who has also been an advocate for a wider array of sample sizes (most runway samples are a size 0 or 2), also says she's faced discrimination due to her weight. "Fat people are absolutely discriminated against. I know this because of the type of modeling I do … If it wasn't, then I'd be all over the runways, every single runway, like everyone else," she says.

Instead, she's had to make her mark in a specialized market – on her own terms. "It's about the healthy eating habits that you have, and wherever your body falls," says Renn. "Whether that is actually a four or an 18, [doesn't matter]." 

"Having had an eating disorder, I was obsessed with numbers and percentages – how many minutes have I been on the treadmill, how many calories have I consumed today?" says Renn. "When you start obsessing about numbers you get nowhere. It really is about, you know, finding balance and moderation within yourself and are you healthy."