"I'll usually have eggs and fruit for breakfast, and I try to do a salad with chicken for lunch. I try to eat really healthy," the Hills star, 22, told Usmagazine.com at the Alice and Olivia fashion show in New York City.
Her diet consists of "proteins and vegetables," and she says she typically eats salmon for dinner. (And she admits on splurging on those "little chocolates" staff members leave in her hotel room while traveling.)
Cavallari says she's too busy promoting her MTV reality show to "sit down and pig out. I'm just on the go so much."
To keep her energy up, she "always has an energy bar with me, just in case I don't have time to eat, which is so bad," Cavallari tells Us. "I'm not normally like that. It's only been the past month. I have low energy, and I get headaches a lot. I need to be better about it."
Cavallari says she's only had time to work out once over the past month.
"I did some lunges and push-ups in my hotel room [before presenting at the MTV VMAs]," she says. "I've been a little stressed out. It's terrible, but stress can make you lose weight, I guess."