The article also mentions she recently started working on the movie Noah.  That movie just recently had a casting call "Seeking the following for Noah, directed by Darren Aronofsky: Caucasian men and women with toned-slender, runners’ bodies who are willing to work at night in the rain." It's very possible she had to lose weight for the role.  Have you seen pics of Matthew McConaughey lately?  He also had to lose massive amounts of weight for the movie he's shooting as well.  Considering how long she's been known for her curves, I can't see her changing her image that much without reason.