On Wednesdays, Fridays, and other fast days, we abstain from meat, dairy, eggs, fish, wine, and olive oil, while increasing our prayers and our giving to the poor.
Meat, dairy, fish, eggs
In poor countries, to this day it is uncommon to have meat in daily meals. A typical meal for many people might consist of rice and beans. Animals are killed and prepared for feasts and to honor guests, not for everyday meals.
So in adopting a rule for fast days, the Church gives us a rule to avoid rich and luxurious foods, including meat and fish, eggs and dairy. Since most cultures in the Mediterranean and the East have traditional ways of preparing peas, beans, lentils, and other proteins, this is not a great change; fassoulieh (Lebanese bean stew) or dal bhat (Indian lentils and rice) are familiar foods.
Fish
In this context, fish speaks of fish with backbones, and does not include shellfish. These are not found far from the sea coast, so they aren’t part of many cultures’ cuisine at all. In fishing communities, some cultures consider creeping things unclean or unfit for consumption, so squid, octopus, clams and shrimp were food for the poor who could not afford decent fish. So our fasting rules developed to allow shellfish on the fast. When frozen shrimp are on sale at the grocery, many Orthodox people stock up so they can add these to soups, salads, etc. But remember this is a fast: Indulging in an expensive meal of lobster or king crab is not helpful when we are trying to eat simply and cheaply.
On certain great feasts, the calendar will indicate that we enjoy fish on a given day.
Wine
While scripture and historical Christianity do not condemn drinking “Wine that makes glad the heart of man” (Psalm 103:16), drunkenness is unambiguously a sin. “And do not be drunk with wine, wherein is excess, but be filled with the Spirit” (Ephesians 5:18). But like meat, wine is a luxury food from which we abstain on fast days.
When a feast falls on a fast day, or on less-strict fasting days, the calendar may indicate that we do partake of “wine and oil.”
Oil
Oil, in English and biblical Greek, originally meant olive oil; the Greek word elaion (oil) comes from elaia (olive.) Nowadays we make many kinds of oil, but any Greek will tell you these are inferior to the rich olive oil that makes foods appealing to the senses. So during fast seasons, the Christians of the Mediterranean until this day make do without olive oil.
Later, Christianity spread to the colder lands of Russia, where all oils were expensive imports (the same word maslo refers to both oil and butter) so in Russia fasting from oil meant all oil and fat.
Your parish community will have inherited one rule or another, and that is what you should follow.
How much to eat
Visitors to America are often surprised at how huge the portions are in our restaurants. Where nutritionists advise us to eat a 4-ounce serving of protein at a meal, we may casually devour a 16-ounce steak together with a stuffed potato. The modern epidemic of obesity may be due to overly processed foods, but it’s a fact that we eat a lot.
The Fathers teach us that we are to eat enough so that we stop being hungry – but then to stop before we’re full. When we have had a plate of food and we are not actually hungry any more, a plate of “seconds” is not necessary; it only satisfies our desire for more.
It may take practice to learn to identify when we have satisfied our hunger. At that point, we can stop eating and not go on to satisfy our appetite, which may lead us into overeating.
Eating to satisfy our hunger, not until we are stuffed, is a discipline for every day, but the fast especially calls it to our attention.
What if I can’t fast?
It is important to remember that the fast is given to us as a therapy – a method that has been found to give our prayers fervency and increase our repentance and compassion. It is not intended to cause harm, and it might need to be adjusted.
We know that very young children need more fat and protein in their diet than adults do, so parents ensure their littlest ones the the nutrition they need. Soon enough the kids can enjoy the same meals the family is eating. Likewise pregnant and nursing mothers, who are eating for two, fast less strictly with regard to foods. Diabetics, and others whose health issues make it problematic to follow these rules strictly, would do best to speak with their confessor, who can ensure that you are not fasting less, but practicing a fast that is healthy for you with a blessing.
Beyond what you eat
“The kingdom of God is not food and drink; but righteousness, and peace, and joy in the Holy Spirit” (Romans 14:17). When we first approach Christian fasting, the chief thing on our mind tends to be what can I eat? But in fact eating less or eating differently is a tool that enables you to do the real work of the fast, which is prayer, repentance, and almsgiving. It would be a sad and even harmful thing to change how we eat, but not to allow the Holy Spirit to change our hearts.
Next: Fasting that pleases God.