The uniform norms for fast and abstinence adopted in 1951 by the bishops of the United States were somewhat modified at their November 1956 meeting. The regulations on this matter now read as follows:
Abstinence
1. Everyone over 7 years of age is bound to observe the law of abstinence.
2. Complete abstinence is to be observed on Fridays, Ash Wednesday, Holy Saturday and the Vigils of the Immaculate Conception and Christmas. On days of complete abstinence, meat and soup or gravy made from meat may not be used at all.
3. Partial abstinence is to be observed on Ember Wednesdays and Saturdays and the Vigil of Pentecost. On days of partial abstinence, meat and soup or gravy made from meat may be taken only once a day at the principal meal.
Fast
1. Everyone 21 – 59 years of age is bound to observe the law of fast.
2. The days of fast are all the days in Lent except Sundays, the Ember Days and Vigils of Pentecost, the Immaculate Conception and Christmas.
3. On days of fast, only one full meal is allowed. Two other meatless meals, sufficient to maintain strength, may be taken according to one’s needs; but together they should not equal another full meal.
4. Meat may be taken at the principal meal on a day of fast except on Fridays, Ash Wednesday, Holy Saturday, and the Vigils of the Immaculate Conception and Christmas.
5. Eating between meals is not permitted, but liquids, including milk and fruit juices, are allowed.
6. Where health or ability to work would be seriously affected, the law does not oblige. In doubt concerning fast or abstinence, a parish priest or confessor should be consulted.
* There is no obligation for fast or abstinence on a holy day of obligation, even if it falls on a Friday.
Source: CMRI.org http://www.cmri.org/fasting-laws.shtml