Bob HarperAs a trainer on NBC’s The Biggest Loser, Bob Harper has become one of the biggest fitness experts worldwide. After earning his fitness instructor’s certification from the American Fitness Training of Athletics Association and the Aerobic and Fitness Association of America, he eventually grew into a brand, which now includes DVDs, supplements, books, ergonomically-shaped Countour Kettlebells, and motivational speaking engagements. His "Inside Out" method, which promises to push people to their highest potential through an integration of mind, body, and spiritual fitness, has already inspired legions of individuals — from everyday people to The Biggest Loser contestants to A-list celebrities — to drop excess weight. Now Harper inspires Healthline readers to get fit with his personal recipe for dietary success, his pick for the most effective fitness trend of 2012, and advice on recognizing a good trainer from a bad one.

How do you motivate yourself to train the more difficult contestants on The Biggest Loser?

I'm a firm believer that you can lead a horse to water but you can't make them drink. So with that said, for any contestant that isn't ready to make a change, there's not really anything I can do.

Do you ever feel guilty about how tough you are on contestants and about sending them home overweight as opposed to non-elimination shows like Celebrity Fit Club?

I would love for all of the contestants to be able to stay the whole time but I'm not a producer so I have no control over that. Regarding the question, ‘Do I feel guilty for being tough on them?’ no, absolutely not. I only have them for a short amount of time and I have to be able to get through to them because I don't know how long I'll have them.

What's the success rate for the contestants sent home early versus the contestants who last till the end?

Harper, doling out some tough love || Harper doles out tough love on The Biggest Loser.I think generally speaking with all of the contestants, our success rate falls pretty much straight down the middle at 50 percent.

Can you explain the whole ‘Inside Out’ method?

It's about changing your behaviors from the inside out. It isn't about a diet or a quick fix; it's about a lifestyle change.  You need to recognize and accept where you are right now, forgive yourself for the past, and be ready to make a change.  When you start to change what's on the inside, the outside will follow.

You were once a vegan poster boy, but I know that you eat animal products again. Why did you go back? How would you describe your diet now?

I found that with the intense workouts that I was doing, I needed to change around my diet to see if I could get better results, and it worked. My diet is a great balance of protein, carbohydrates, and good fats. I stay away from starchy foods and have only a little sugar.

Who's the one celebrity you'd love to train?

I was a huge fan of Lost and Jorge Garcia, who played Hurley, would be someone I feel like I could help if he was looking for it.

Which is preferable in your opinion, gym workouts or outdoor bootcamps? 

I like being able to get great workouts in the gym to better my performance in outdoor activities.

Bob Harper, posing.

What is the single greatest obstacle in starting a health and fitness routine and how can someone overcome it?

I think the biggest obstacle is in fact just getting started. They have to really want to do it and then the rest will come.

What is the most effective fitness trend right now?

CrossFit.  The workouts just make so much sense.

How can clients recognize a good trainer from a bad one at their local gym?

You should always ask what certifications trainers have and make sure you feel comfortable with them.