It could be a lot of things. Stress, problems in the family, etc. I mean she's always been naturally thin but when I saw her in the gold dress I was just shocked. I thought of Mary Kate (or was it Ashley?) Oslen when she arrived on the scene with her ribs sticking out like Keira's did and I predicted it could be nothing but bad for her reputation in the public eye. Women these days want actresses who aren't afraid to be full size not ones that appear they have caved into the eating disorders of hollywood. Not saying Keira has, but it appears so. As fans, we know this isn't true, but the media loves to feed anything juicy like this to the public who doesn't know her any better. And especially since Keira is the 'good girl' of hollywood these days who hasn't even made a scene in a bar or had an unpaid parking ticket to speak of, the Star magazines will be ALL OVER this.
Poor Keira...she really has to steer clear of those all too revealing dresses.