Kelly Osbourne always cheats on her diet.

The 'Fashion Police' co-host - who is dating vegetarian chef Matthew Mosshart - has lost 70lbs since 2009 but still allows herself to indulge in ''cheat meals'' and has a weakness for pizza.

The 28-year-old star told The Huffington Post: ''Once I learned how to work out right and eat right, it's one of those things that you just have to commit to a life change rather than being on a diet. Because a diet doesn't work. You lose weight and you stop it and it will all come back. So you just have to take baby steps, commit to something and stay true to it.

''And everything has to be in moderation and to find that place is easier said than done. It really is. Everyone's like, 'Oh it's all about moderation!' I'm like, well what are you going to do with a plate of French fries in front of you, moderate? No. You're going to eat every single one of them!

''I always cheat. Pizza, I have to say ...''

Kelly recently admitted she has never been happier with her body.

She said: ''I'm the most secure and content I've ever been. Though I'm still very self-deprecating. I look in the mirror sometimes and I feel like going back to bed. Everyone has good days, everyone has bad days.

''The only thing I can be is me. I'm not perfect. I make mistakes. And my body is not perfect, either, but I love it.''