But their sexy image was built upon a lie. Their hourglass figures were possible only because of an ugly eating disorder. "I just remember the pain that we went through...the suffering that we did for each picture," says Shane.
Weeklong fasts to lose weight for fashion shows and photo shoots were followed by bouts of non-stop eating. "I went feast and famine, feast and famine. That was my whole life. There was no such thing as sitting down to a normal meal," says Sia.
The sisters deny using cosmetic enhancements and claim their bodies are the result of a super-human exercise routine. "I did 10 hours of exercise seven days a week," says Sia. "I was in so much pain all the time."
Eventually, the sisters developed full-blown bulimia - Shane would vomit, Sia took laxatives. At one point, the two - 5 feet 9 inches tall - weighed just over 100 pounds each.
Rock bottom came when Sia collapsed after taking more than 100 laxatives "It looked like she had a cardiac arrest or she was paralyzed on the right side," says Shane.
She got immediate medical help and recovered from her overdose, but her doctor warned her that if she didn't stop, she would die. Shane's husband encouraged them to attend meetings of Overeaters Anonymous, a 12-step program.
They have written a book and are touring high schools and colleges, telling young women not to make the same mistakes they made.
But critics say the image of perfection they presented in their modeling careers makes the Barbi Twins imperfect spokespersons for young impressionable women.
"It was a lie. OK, it was a lie and we are coming clean now." responds Shane.
The Barbis now have a new health and fitness calendar - only this time they didn't kill themselves to pose.