The Grey’s Anatomy star, Katherine Heigl, has turned to trainer Harley Pasternak to slim down for her wedding.

Until recently, Katherine Heigl wasn’t exactly a health nut. “I hate dieting. I hate the whole thing!” the 5-foot-9 Heidl once complained.

And exercise? The very idea of it made her cringe. “It’s the most boring thing in the universe,” she said. “I have a hard time motivating myself to pretty much doing anything that takes any extra energy.”

But suddenly, she got the motivation she needed: A nearly naked love scene in the movie Knocked Up, coupled with her impending nuptials, sent the 28-year-old Heigl running to LA trainer Harley Pasternak, creator of the 5-Factor Diet.

“When I started with Katherine she was beautiful,” Pasternak, says the man behind Jessica Simpson’s amazing bod, “but now she’s even more of a model of health.”

How it works Katherine started with the program’s food-delivery service, but “she’s been independent with it,” Pasternak says. “She quickly picked up the concept, and now she does it on her own and doesn’t worry about counting calories.” (In fact, Pasternak never weighs a client or counts calories, though he says the range starts at 1,300 calories a day.)

And the concept behind 5-Factor Diet is simple: The magic number is five. Every day, Katherine eats five meals that fulfill five criteria – and she can even cheat once a week. Says Pasternak, “It dispels most of the myths of dieting. It’s a diet you see yourself doing for the rest of your life.”

Katherine Heigl’s brand-new anatomy Pasternak makes going to the gym easy. Katherine hits her trailer during lunchtime for 5-Factor Fitness – 25-to-50-minute workouts that begin and end with cardio and mix arm, leg and ab moves in between.

Katherine looks great and more importantly, feels great. “I used to have back pain,” says Katherine. “Suddenly, my body is supporting itself the way it’s supposed to. I wake up and say, ‘My God, I can’t believe this is my body!’” [via]