The Edible Woman by Margaret Atwood

Marian is determinedly ordinary, waiting to get married. She likes her work, her broody flatmate and her sober fiancé Peter. All goes well at first, but Marian has reckoned without an inner self that wants something more, that calmly sabotages her careful plans, her stable routine - and her digestion.

Marriage à la mode, Marian discovers, is something she literally can't stomach . . .