Abstract: A selection of the Migne anthology on Sacred Orators provides about fourty sermons dating back to the 17th – 19th centuries which enables to present a synthesis of Catholic teaching on fasting at that time. The latter constitutes a social marker of Catholicism but the Church finds it difficult to impose its rule in the 19th century. The biblical references make it possible to consider fasting not only as a precept of ecclesial right but of divine right ; moral considerations, an urge to penance and self-mastery with hygienic aims, make up the basis of those sermons. The preachers entrust to the confessors the care of applying that rule to special cases on the grounds of the Theologia Moralis by Alphonse de Liguori. The apology of fasting throws into light a common philosophical culture of platonician inspiration, nurtured with patristic quotations : an opposition of soul and the body, a reduction of the human to the spiritual, in a pessimistic atmosphere, hostile to the body, preaching a moralizing practice of an active ascesis.
