Catholics between the ages of 18 and 59 are obliged to fast on Ash Wednesday and Good Friday. In addition, all Catholics 14 years and older must abstain from meat on Ash Wednesday, Good Friday and all Fridays of Lent.
Fasting as explained by the U.S. Bishops means partaking of only one full meal. Some food (not equaling another meal) is permitted at breakfast and around midday or in the evening - depending on when a person chooses to eat the main or full meal.
Abstinence forbids the use of meat, but not of eggs, milk products or condiments made of animal fat.
Abstinence does not include meat juices and liquid foods made from meat. Thus, such foods as chicken broth, consomme, soups cooked or flavored with meat, meat gravies or sauces, as well as seasonings or condiments made from animal fat are not forbidden. So it is permissible to use margarine and lard. Even bacon drippings which contain little bits of meat may be used as a seasoning.