Ok so it isn’t what you think. Nothing but vodka for long periods at a time…It’s more like replacing wine with vodka because it has fewer calories. Reports are that Sienna Miller had to get down to a size 0 for her role in ‘Factory Girl’. She also ate egg white omlettes (egg whites have 17 calories in each)

What Does Sienna Miller Eat?

Egg white omlettes and vodka have been confirmed. She claims that she eats all the burgers she wants. From the research I found I believe Sienna Miller eats low calorie meals and practises portion control (eating small portions of food and stopping when you are hungry. This is what all of the Hiltons do)

How Does Sienna Miller Workout?
“Rope yoga works mainly on the abdomen, hips and thighs,” she says. “It’s about toning and stretching rather than calorie burning, and it’s effective in releasing tension. “I thought, Okay, I’ll drink vodka instead of wine because it has less calories.”