The former Hills star - who is in the second trimester of her pregnancy with American football player Jay Cutler - admitted that she is still getting used to not fitting into clothing made for models.
Cavallari told Celebuzz: "I have this thing called the Belly Band that just goes around the top of your jeans so you can wear them without buttoning them. It's the first time I've had sample size dresses not fit me. It's all for a good reason. It's alright. I'm pregnant."
The 25-year-old - who made her name on MTV's Laguna Beach reality series - added that she has been consuming plenty of dairy products thanks to expected cravings.
Cavallari said: "Ice cream, yogurt, cottage cheese... anything dairy, I had to have it and I am out of that now. I have been eating a lot of Twix, which I don't typically eat, but that is it.
"I'm trying to balance it out by eating healthy as well."
Cavallari also revealed she knows her baby's due date and has been discussing names with her Chicago Bears player fiancé.
"We have been throwing around a few name ideas, but once we find out if it's a boy or girl it will be easier to pick," the reality star said. "I find out [the sex of the baby] at my next appointment. I am dying to know, once I find out though I am probably not going to tell."
> Kristin Cavallari: 'I'm not shopping for wedding dresses'
Watch Kristin Cavallari perform on Dancing With the Stars 2011 below: