Jillian Michaels: MMA is the best single exercise
Time: If you could do only one exercise activity for the rest of your life, what would it be?
Jillian Michaels: Mixed martial arts. It’s a great way to stay fit, stay toned, stay lean. I love yoga, but the namaste thing only takes you so far. Every now and again, you just gotta hit something. Not someone — something.
Time: You push people to their fullest potential. Who pushed you?
Jillian Michaels: My martial-arts instructor, who worked with me until I was about 21. He changed my life. He demanded that I live up to my potential, and if I didn’t, he was like, “I’m not wasting my time. Either meet me halfway or don’t bother.” (See TIME’s photo-essay “What the World Eats, Part I.”)
Time: There are numerous video clips of The Biggest Loser in which you smile or laugh when “breaking” a contestant. What are you thinking when you do that?
Jillian Michaels: I enjoy watching them struggle with something that seems insane. They’re just like, “You can’t be serious. You must have lost your mind.” But I know that they’re going to achieve [their goal]. I wouldn’t think it was funny if they couldn’t do it. (See pictures of Jillian Michaels.)
Time: Why did you become a personal trainer?
Jillian Michaels: I fell into it. I was 17, training for my black belt. I would be in the gym hanging upside down from a gravity boot doing inverted sit-ups, and people would be like, “Oh, you must be a trainer.” And I was like, “Of course I am.”