Let us begin the all-holy season of fasting with joy;Re-post from last year regarding the full Lenten practice for Latin Rite Catholics and which parts of it are obligatory under pain of sin:
Let us shine with the bright radiance of the Holy Commandments of Christ Our God:
with the brightness of love and the splendor of prayer,
the strength of good courage and the purity of holiness!
So, clothed in garments of light, let us hasten to the Holy Resurrection on the Third Day,
that shines on the world with the glory of Eternal Life!
-Greek Matins for the first day of Great Lent (cf. Rom 13:11-14:4; Mt 6:14-21)
If this sounds too hard or strict consider that in the Eastern Rites, every day of Great Lent, including all the Sundays, is a day of strict fast. Strict fast is a day of fasting where no meat or dairy is allowed. Meat has a stricter definition as it includes all parts of the animal and in most places also includes vertebrate fish. Dairy includes all animal byproducts: milk products, eggs, lard, the whole nine yards. Some jurisdictions include oil products as well in addition to meat and dairy, but only during the week. So the traditional Latin practice is nice and easy...
Lent is nigh. Here are the traditional fasting rules and what is still binding under pain of sin today:
Abstinence from meat: Meat is defined as the flesh of warm-blooded animals (mammals and birds) and broths/sauces made with or from such animals. Cold-blooded animals (fish, reptiles, frogs, etc.) are allowed. Abstinence begins at age seven and becomes obligatory under pain of sin at age 14.
Fasting: Obligatory under pain of sin for those ages 18-59 (formerly 21-59 in the 1917 Code). Fasting limits food to one full meal and two partial meals that do not add up to a full meal. Beverages are unlimited. Fasting can come with either full or partial abstinence. Full abstinence forbids meat at all three meals. Partial abstinence allows meat at the full meal only.
Ash Wednesday, all Fridays, Good Friday, and Holy Saturday are days of fast and full abstinence. Mondays through Thursdays as well as Saturdays are days of fast and partial abstinence. There is no penance on Sundays. Fast and full abstinence is obligatory under pain of sin on Ash Wednesday and Good Friday. Full abstinence (but not the fast) is obligatory under pain of sin on all Fridays. On I Class Feasts, the penance is not removed from the day but the obligation under pain of sin to observe it is removed. In some countries, Saturdays of Lent are days of full abstinence and not partial.
Canons 1250-1254 of the 1917 Code of Canon Law
Canons 1249-1253 of the 1983 Code of Canon Law