One word: Diet.
"I tried to cut out a lot of sweets," Kardashian, 28, told reporters after Thursday's show. "And I love ... cheese. [Cheese] is not a sweet, but ... I don't care."
An admitted cheese-o-holic, she likes "cheese on anything, I don't care. ... [I] binge eat," she says, then, with a laugh, adds, "and cry."
Kardashian does take shaping up seriously: "It's always going to be a lifelong thing for me. And I'm not where I want to be."
Still, she's gained some perspective. "When I used to do things like crash diets or things too fast, it never stuck because it wasn't a lifestyle change," she says. "So for this, I'm working out consistently like three to five days a week … It's been harder. But I'm just changing my diet slowly."
As for how she looked on the show, Simon Cowell went so far as to say on-air that her nipples were showing. How did Khloé feel about that?
"I didn't mind that he talked about it," she says. "Because it was there! Like, if you didn't talk about it, it would have been weird."
Her wardrobe limitations could be blamed on Hurricane Sandy. "My stuff got stuck on the East Coast, so the top I wanted to wear came in that day. I was like, 'Oh, perfect' – and we didn't have time to do it full dress rehearsal."
The actual top "was lined with a nude lining," and "we double taped it," but "the first time I ever went onstage was when it was live! So Simon was looking at me and going like this [gestures pointing to her nipples], and I was ... covering it with my hair, and I thought, from my angle, maybe it was just ... nippily."
Recalling the awkward moment that was unfolding before millions of TV viewers, she said, "Why did this happen to me? Am I going to get fired? So when [Simon] said it, it kind of broke the ice."