Wintergirls by Anderson

Lia walks a thin line between life and death. The line is one she drew herself. Driven by self-loathing and haunting visions, Lia cuts and starves herself in an effort to prove her strength and control. When Lia's friend steps over the line and dies alone after leaving Lia 33 messages, Lia's downward spiral turns into a nosedive. This book is intense. Anderson pulls no punches as she describes reality as seen through the lens of eating disorders. It's horrible and painful and wonderful and important all at once. It gets pretty bleak at times, but if you know someone suffering from an eating disorder, it's worth it.