"I'd rather starve than be fat," says 22-year-old Julia. But at 5-foot-7-inches and 95 lbs., the frail girl is compared by her Polish parents to survivors of Auschwitz.

Julia's story was featured on last week's episode of our favorite reality show, A&E's "Intervention." As a young teen, when Julia developed earlier than her identical twin, she began exercising to lose weight.

Her sister, Sonia (three minutes younger and 3 inches shorter) who'd clung to her newfound identity as "the thin twin" followed suit.

A Deadly Pact
The girls' sisterly competition soon gnarled into a shared eating disorder. When the show was shot, the twins consumed about 300 calories a day, counted each others' steps to guarantee they burned equal calories and weighed their food before eating it, counting each piece of rice.

They also had a pact that they'd always weigh within 3 lbs. of each other. "I don't feel like we're two people sometimes," says Sonia. "We're one person." (Click here to see video of the girls.)

We spoke with the show's interventionist, Ken Seeley, author of the new book "Face It and Fix It" about their incredible story.

Click Next below to find out more about the girls -- and why their behavior is less rare than you might think.

More from around the web:
What it's like to live with anorexia (AOL Health)

A weird way to end insomnia? (Health.com)
Get healthier while you watch TV -- really (Lemondrop)