What happened to Marissa Cooper? Girl looks so much more, er, developed now!

Mischa Barton has been on a downward spiral in the looks department lately, but perhaps she's trying to change for the better. We spotted the former O.C. starlet running errands in Santa Monica today, first stopping at the DMV (to renew her driver's license) and then shopping for health food! Hopefully she's on a new diet plan? Those pants are preeeeetty tight.

Now if only she could get a better acting job than playing a hooker on Law & Order!