It sure sounds like another shameless reality-TV formula: Inspire people to slim down by offering them cash, then film their struggles with health food and sit-ups. But personal trainer Bob Harper, 43, of NBC's The Biggest Loser, feels no shame at all. The show lets him introduce his holistic fitness approach to people far removed from L.A., where he's sculpted celebs like Ben Stiller. RYAN KROGH checked in with the ever-enthusiastic runner, cyclist, and tennis nut a few weeks before The Biggest Loser's January 6 season-seven premiere.

OUTSIDE: What's the best thing about your show?
HARPER: I love that, every season, somebody gets their life changed. It's rewarding to show people who, no matter how far they've gotten off track, can pull themselves back on course.

Where do you start?
I try to get them to look at the big picture—to see that they have it in them, that inner strength and resolve. Once they tap into that, they become unstoppable.

Even if they hate exercise?
It's about being active. If you don't like going to the gym, there are plenty of other things you can do—go on a hike, take your family to the beach, get on a bicycle team.

What do you say to someone who already understands that?
To me, it's about keeping your head in the game. Shows like mine keep you thinking. When fit people get inspired [to try something new], that's a big success as well.

You compete for money on the show, too—against the other trainers.
Of course, there's competition there. But to me it's about helping every single person that I can. At the end of the day, there is only one winner on the show, but everyone who comes on has the opportunity of winning for a lifetime.

Are you always this positive?
It sounds like a Miss Amer­ica answer, but it's honestly what I believe.