The medieval phenomenon of anorexia mirabilis—as kaytay terms it above, "miraculous loss of appetite"—was often accompanied by other forms of asceticism, including chastity (often enforced by starvation, when the hungry saints grew too weak for any physical activity, let alone sex) and self-mutilation (Catherine of Siena, for instance, experimented with auto-flagellation when she was as young as six or seven).
Some related "fun" facts from A History of Celibacy (Elizabeth Abbott, 2000):
At the age of fourteen, the aforementioned Saint Catherine of Siena had a vision of a mystical marriage to Christ, and pledged her virginity to her Husband. She refused to marry, cutting her hair to make herself unattractive to potential suitors, and starved herself until her parents gave in and found her a place in a convent. There, Catherine strove to overcome all physical desire, to the point of drinking pus to conquer her revulsion towards physical decay. When she eventually died at the age of thirty-three, just as her Husband, there was so little left of her that her death was probably just another act of her fierce, forceful will.
Saint Columba, also known as Columba di Rieti, wore hair shirts and mutilated herself with spiked chains across her hips and breasts. Her self-inflicted wounds were so severe that "a gang of would-be rapists who stripped her were too awed to consummate the deed" (126).
In an age where their gender limited their options to matrimony or the convent, these devout women sought fame through sainthood with an extreme asceticism that bordered on the exhibitionistic.