What better way to detract from the jutting bones and sallow skin than yards of flowing fake hair? That's not to say that Katie's an out-and-out anorexic, but I think it's safe to say that she's pretty much cleansed every part of her body she can without losing consciousness.
I always thought Katie looked better with long hair, but that could just be that she's just looked so trapped and miserable since she's been hacking her hair shorter and shorter. Could be the misery has nothing to do with her hair. Could also be the hair is a form of acting out against the iron mantle under which she toils.
Hollywood's stars need to get over the "thin is in" mentality. These girls starve themselves down to a fraction of their normal healthy weight. If not for the stylists, hair and makeup people working overtime to make them beautiful they would look like refugees. Katie looks ten years older since she got married. That can't be because she's "amazing"-ly content.