Barton at the Golden Globe Awards

The former 'The O.C.' actress insists she has never tried a "fad" eating plan, but thinks occasional liquid regimes are good for her, as they give her energy and all the nutrients she needs.

She said: "I've never been on a fad diet, but I've been juicing for years and I love it. Juice gives me energy and fills me up when I don't have time to eat other things.

"You get so many nutrients so quickly out of it. I strongly believe in those things, like the health benefits of juicing with cayenne pepper."

Although Mischa tries to eat well, she can never resist bacon - and her love of the meaty treat was enough to convince a former boyfriend to give up being a vegetarian.

She said: "My biggest food weakness is bacon. I once dated a vegetarian and turned him into a meat eater. It's bacon that gets me every time, as soon as I see someone eating it. Mmmm..."

The 27-year-old actress thinks her weight fluctuates so much because on long days of filming, it makes it hard to work out.

She told Look magazine: "Before a project, I usually take a couple of weeks to really get in shape and start getting fit. Once I start working, I have 6am call times and won't finish until 11pm so going to the gym before or afterwards is difficult."