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Nicole Richie

In 2006, the 5'2" socialite weighed only about 90 pounds—dangerously thin even by Hollywood standards—and sought treatment for her weight issues. Many speculated she was suffering from an eating disorder, although she never spoke openly about it.

Richie, 29, who has two children and was recently married, has remained slim, but appears to be at a healthier weight than at her thinnest.

Next: Seth Rogen