Nicole Richie is seeking treatment for her weight issues.
Her rep told people:
Nicole Richie has decided to undergo diagnostic treatment to determine why she's not been putting on any weight, 
She is working with a team of doctors and specialists whose focus is nutrition. It is important to Nicole that she achieves this goal in a healthy way as this is not a treatment for an eating disorder. 
Nicole Richie's thinness has been the subject of much debate – which she addressed in May when she told Vanity Fair magazine:
I know I'm too thin right now. I'm not happy with the way I look right now." She also said at the time that she was consulting with a nutritionist and a doctor, but blamed her weight loss in part on the breakup with her then-fiance, Adam "DJ AM" Goldstein. 