Kat Dennings Embarks on Healthy Eating Challenge

— -- Kat Dennings is ready to break some bad habits. The "2 Broke Girls" star is embarking on a month-long challenge to eat healthier.

The 28-year-old actress posted a photo to Instagram marking her first day on the Fit Girls Guide's 28 Day Jumpstart, which strives to get girls and women fit through healthy eating.

Alongside a photo of her first meal of brown rice, carrots, roasted tomatoes and hummus, the actress wrote: "To explain, I realize as I've grown older (28 cough cough) that I still eat like a teenager. Candy when I'm bored at work, stress eating, snacking at night, etc, and that's completely allowed and a natural part of being a human BUT I want to start making more of an effort to put health on the front burner as I coast into the eventual dark abyss/exciting new world of my 30s."

Dennings has been dating singer Josh Groban since last fall, after the couple met through Dennings' co-star Beth Behr.

"Yeah, she's always talked about how great he is," Dennings told "The Ellen DeGeneres Show" last October. "They've been friends for years. And she thought we were both, you know, nerds. So there, she was right."