Hunger by Jackie Kessler

Lisabeth Lewis is seventeen and anorexic. When a friend confronts her about it, she decides it's time to end everything and tries to commit suicide. But she's interrupted by a young man with a package and a command, "...go thee out unto the world." The package is a Scale. Lisabeth has just become Famine, one of the Four Horsemen (women?) of the Apocalypse.

Of course, she believes it has all been a dream. However, she can't ignore the Scales that appear out of nowhere (that no one else can see) or the black horse in her backyard eating her mother's flowers. Or the riot she starts in Sydney, thousands of miles from home.

Once Lisabeth learns what real hunger is like from villagers eating dirt cookies, how can she continue to live like she has been? And how can she use this power to help instead of hurt?

An interesting concept--I've never read anything like this anyway. Lisabeth is a hard character to really like at first, but she has many redeemable qualities as the story goes on. There are amusing parts (especially when Death is singing) and the ending is especially moving.