06/28/2012 at 12:00 PM EDT
makes a pretty impression whether she's sporting a leopard-print mini dress
... or a pair of sweatpants
But when asked whether she felt comfortable with her body, the reality star, 31, had a difficult time giving a straight answer.
"I think so, for sure," she said Thursday on the U.K.'s ITV Lorraine show
, before changing her answer. "Well, no, I'm such a perfectionist. I don't think I'm ever really comfortable."
It's a departure from the confidence she boasted to PEOPLE in 2009
, when a bikini-clad Kardashian proclaimed, "I'm comfortable in my own skin."
One of her biggest insecurities? Her thighs, Kardashian told Lorraine Kelly. "I still have some cellulite," she said, describing Spanx as "the greatest invention."
However, when it comes to staying in shape, she credits the gym more than the kitchen.
"I don't eat as good. I work out all the time," she said. "I train myself to eat healthier, then I obviously look better."
She says she also uses QuickTrim, a dietary supplement and cleanser that she and younger sister Khloé
launched with GNC, "right before bikini seasons or before [photo] shoots."
But for Kardashian, who has been dating Kanye West
since April, there's one thing she won't complain about: spending time with her nephew, Mason Dash
, expectant sister Kourtney
's 2½-year-old son with Scott Disick.
"I love being an aunt," she said. "I'm, like, obsessed with my nephew. He's just like the best thing that's ever happened to our family."