CENTENNIAL - Contestants on The Biggest Loser see life-changing weight loss results, but those looking to shed some pounds don't have to be on the TV show. As a part of 9NEWS' Workin' It Out, Workin' It Off" series- 9NEWS visited a Colorado gym that revolves around an exercise program called CrossFit.

This high intensity, heavy weight, fast-paced workout that requires accuracy and skill has become wildly popular over the last few years.

Nathan Whitman is the owner of Method Crossfit in Centennial and says Crossfit is designed for everyone from professional athletes to couch potatoes.

"People are used to the old hour on the cardio machine and lift weights for an hour. Here's the workouts are five to 25 minutes long and because of the movement we can work out in a shorter amount of time but the intensity is higher," says Whitman. "That short, quick, intense workout is where you really make a difference."

Another big difference between Crossfit and other exercise programs is that heavy weights are part of the daily workouts.

"Everyone should be lifting weights. I know woman always say, 'I don't want to get bulky, I don't want to get big.' It's not gonna happen. Most woman don't produce enough testosterone to ever get big like that," Whitman said.

Bobby Bonham, previously known as "Big Bobby," was introduced to Crossfit five years ago at the age of 50.

"He was the prototypical American. He was on all kinds of medication, he was overweight and His doctor even said if he keeps this up he will die," says Whitman.

"I was 265 pounds; I was obese," Bonham said.

After months and months of putting in the work and eating right, Bonham lost 70 pounds of fat, gained 15 pounds of muscle, lowered his cholesterol - the list of positive side effects goes on and on.

"[I say] eat right ,show up and do the work...those are the things you have to do," Bonham said. "No one is going to do it for you."

For more information about CrossFit visit Method's website:

Rose Heaphy contributed to this article.