"It started around 2012," she told the magazine. "I was having a hard time with [husband at-the-time NBA star] Lamar [Odom]. It was toward the end of our union, and there was so much drama. I needed a release. At first it was so hard. It was baby steps, but I started feeling so much better."
The 31-year-old used began exercising with celebrity personal trainer Gunnar Peterson, who recently spoke to ET about her workouts. "Khloe's an animal...No complaining, no bitching, just gets after it," he said.
Her fierce attitude helped her achieve what she calls her "revenge body." She admitted to the mag that Lamar was not the only one on her mind at the gym, saying, "It's just as much for all my critics who called me 'the fat one' for my entire existence."
In fact, her beautiful bod even served as inspiration for her fashion designer brother-in-law, Kanye West.
"Kanye was like, 'I want you to come and be a fit model,'" she recalled, referring to his New York Fashion Week presentation of Yeezy Season. "And I was like, 'Did you mean to call Kylie?' And he was like, 'No, I'm calling you. Your body vibes are my influence this year.'"
As for the vibes Khloe has been feeling, she still feels love for her ex. "I love Lamar to death," she admitted. "He is the love of my life. We had a fantastic marriage. Do I wish he had tried harder? Yes. Do I think that he maybe didn’t have the energy to fight because he was fighting so many other things? Yeah."
"I know she's Caitlyn now, but she's still my father figure [in the same way that] single mothers can also take on both roles," she shared. "We want her to be as happy and free as she needs to be. I tweeted that we're all transitioning, assuming that people would understand that we were adjusting emotionally, not that I was implying we were all going through the same changes. I wasn't trying to offend anyone. I'm learning. We're all learning. It's just hard to learn when millions are watching."
Khloe's September cover of Women's Health hits stands this week.