U.S. actress Jennifer Aniston poses for photographers as she arrives for the British premiere of "Marley & Me" at Leicester Square in London March 2, 2009. [Agencies]

Jennifer Aniston insists she wouldn't win movie roles if she ate burgers.

The 'Marley and Me' actress claims watching her weight is part of her job, adding she knows she is often offered parts because of her slender frame.

She said: "I'm a realist. I know that if I eat nothing but burgers and chips, I'm not going to be hired for the parts I normally would. That might be fine one day, but not right now."

Jennifer is adamant reports she is still obsessed with her ex-husband Brad Pitt - who now raises six children with partner Angelina Jolie - are untrue, claiming she is now happier than ever.

The 40-year-old actress - who is dating singer John Mayer - added to Britain's Elle magazine: "No matter what I say, things will always be taken out of context and misinterpreted, will always be turned around to make it seem as though I won't let something go, or that I just keep talking about it over and over.

"I don't owe anybody anything. I don't owe anybody my side of the story. There are no sides! There is no bad guy and there is no good guy. There are no villains and there is no heroine in this story. It's just not the case."