Chapter I. On the Essence and Obligation of Fasting

489. • I. All the faithful, from the completion of the twenty-first year of age, are bound under grave sin to observe the fast on the stated days, unless they are legitimately excused or are dispensed by Superiors. It is a most ancient obligation, which is said to have been handed down by the Apostles themselves. Moreover, concerning this obligation it is established from various Constitutions of the Supreme Pontiffs, and from all the Catechisms of the ecclesiastical Provinces.

I said, 1. under grave sin, because the law regards grave matter, since indeed it very much conduces to the salvation of souls. It is established besides from Proposition 23 condemned by Alexander VII, which lies thus: "One breaking the fast of the Church to which he is bound does not sin mortally, unless he does it from contempt or disobedience, for example, because he does not wish to subject himself to the precept."

I said, 2. from the completion of the twenty-first year; because the Church, as a pious mother, does not wish to impose on boys and adolescents a law surpassing their strength. It is established from universal custom, and from all Catechisms.

II. Ecclesiastical fasting consists of three things as of parts, namely: 1. one meal through the 24 hours of the day, with a little evening refection added; - 2. abstinence from flesh meats and milk products ¹; - 3. a determined time for taking the refection. - Notice, however, that the custom of places and times contributes especially to determining, or modifying, or restricting the nature and obligation of fasting.

¹ This must be restricted according to the things which are to be said below, n. 503.