The former "American Idol" talks diets, fashion and dating in the December issue of Glamour magazine -- and ET has your sneak peek.

Country cutie CARRIE UNDERWOOD has glammed up some since winning the "American Idol" title two years ago. Now, the Grammy Award-winning singer reveals her secrets in the new issue of Glamour magazine, on newsstands Dec. 11.

"I'll go home and one of my friends will say, 'Oh my, gosh, those shoes are so cute.' And I'll say, 'Oh, they're CHRISTIAN LOUBOUTINs.' They're like, 'What?' So yeah, I've definitely learned more names."

Carrie is also wearing a smaller size these days, and she says she is okay talking about the weight-loss because she shed the pounds the healthy way.

"I work out," she tells the mag. "I like cardio. That big exercise ball, we're friends. I'm slightly obsessive-compulsive about what I eat, more than I should be. I write down everything I eat ... I started doing it last year. And in the last year is when I've gotten more healthy and lost weight."

An animal lover from way back, Carrie is a vegetarian, which not only effects how she eats, but also who she can date.

"I don't think I could kiss someone after they ate a hamburger 'cause they would probably taste like it, and that would gross me out," she reveals.

Even with her new look, the multi-platinum selling artist says there are still things she won't do. She still won't show her stomach, and she is careful about her décolleté.

"Cleavage can be done in a tasteful manner -- you can be intelligent, sexy and not have boobs everywhere," she declares.

The small-town girl does have her splurges. She will spend a couple of hundred dollars for True Religion jeans, and she drops some serious cash every time she goes to Sephora.

"I have a giant makeup case, more makeup than any girl should have in her lifetime," she admits.