Book Girl (2006)

Blurb:
For Tohko Amano, a third-year high school student and self-styled “book girl,” being the head of the literary club is more than just an extracurricular activity. It’s her bread and butter... literally! Tohko is actually a literature-gobbling demon, who can be found at all hours of the day munching on torn out pages from all kinds of books. But for Tohko, the real delicacies are hand-written stories. To satisfy her gourmet tastes, she’s employed (rather, browbeaten) one Konoha Inoue, who scribbles away each day after school to satisfy Tohko’s appetite. But when another student comes knocking on the literary club door for advice on writing love letters, will Tohko discover a new kind of delicacy?

Source: www.anisearch.com/manga/6444