Ash Wednesday and  Good Friday are obligatory days of both fast and abstinence from meat. 

When  fasting, a person is permitted to eat one full meal per day. Two smaller meals, sufficient to maintain strength, may also be taken according to each one's needs, but together they should not equal a full meal. Eating between meals is not permitted, but liquids, including milk and fruit juices, are allowed. For members of our Latin Catholic Church, the norms on fasting are obligatory from the 18th birthday until the 59th birthday.

All Fridays of Lent are obligatory days of abstinence from meat.

Abstinence means not eating the meat of warm-blooded animals (such as beef, lamb, chicken, and pork). Fish and all cold-blooded animals may be eaten (such as shrimp, frogs, and clams). All those who have reached their 14th birthday and older are bound by the law of abstinence from meat.

Abstinence from meat on other Fridays of the year is recommended but not required.