Kristin Cavallari has admitted she's a ''freak'' about what food she puts in her mouth.
The 27-year-old beauty credits her strict eating plan for helping her bounce back into shape just 12 weeks after giving birth to her second child Jaxon.
Speaking to E! News, she said: ''I'm a freak about what I put in my mouth. I'm constantly reading labels and I don't eat any toxic chemicals, so I think that plays a huge role [in the weight loss].''
The former 'The Hills' star also thinks breast feeding has encouraged her weight loss, as well as receiving good genes from her mother.
She added: ''I'm breast-feeding, which burns a ton of calories, and I can probably just thank my mama too, you know.''
Meanwhile, Kristin admits her and her husband Jay Cutler's eldest son Camden, 22 months, had initially settled into life with a new baby brother around, but things have taken a turn for the worse recently.
She explained: ''He's been great, up until the last two days. Yesterday I was feeding Jaxon and he threw a sippy cup at his head and started to kick him, so we're sort of in that phase right now.''