The Hills star told People that she'll eat "whatever they'll make me eat" to win the show.
"I want to know for myself that I can do these challenges and that I'm as tough as anyone in the world," she said. "I'm not afraid of anything."
The reality TV star also admitted that her husband Spencer would be her "biggest competitor".
"He takes no prisoners. I'm worried he'll push me over a cliff to get to first place," she said.
She added that she hopes the series will let people see "a more down to earth" side of her husband and herself.