"Keeping Up with the Kardashians" star Khloé Kardashian is looking more slender and sexier than ever before thanks to a routine of weightlifting, cardio and fierce dedication.

"She's in love with fitness," her trainer Gunnar Peterson told People magazine.

Peterson has been working with the 31-year-old reality TV star for three years. He said that she never misses a workout.

Kardashian told Australian radio hosts Fitzy and Wippa that she enjoys fitness.

"I'm so into it," she said during an interview for NOVA FM. "Even this morning, I've been up since 2:30 because I was jetlagged and couldn't sleep, and I still went to the gym this morning."

Earlier this year Kardashian revealed to People that she exercises "almost every day." Her five-days-a-week sessions with Peterson last for an hour.

"Some days it's more heart-rate intensive, some days it's more lower-extremities intensive, some days the upper extremities get a little extra love," the celebrity trainer said, adding that he uses bigger movements rather than isolated movements to tone muscles.

Kardashian frequently shares social media photos of her workouts, many of which include weightlifting. Weightlifting is essential to weight loss, according to her trainer.

"You have to challenge your body with an external load," Peterson said.

Boxing is another exercise added to her workout regime.

"[Boxing is] great for the heart rate, great for hand-to-eye, great for balance," he said. "It's good for your body to contract upon impact."

Kardashian's 35-pound weight loss could not have happened without a healthy diet and proper nutrition.

"You can't out-train a bad diet, and you can't out-diet a bad lifestyle. She's made better choices when she eats. She's been more conscious about working on sleep habits. She hydrates better," he said.

She has lost the weight, but that doesn't mean this Los Angeles native plans to cut down or stop her fitness routine.

"She keeps getting after it and she keeps getting better," Peterson said. "We're always playing with [our workouts]; we're always making it that much more challenging."