Our Roman Catholic counterparts get their fasting regulations from the 1983 Code of Canon Law (regarding which days are fasting days and days of abstinence). The Code gives powers to the Episcopal Conferences in the regions to “more precisely determine” the rules of fasting in the area. Everything is regulated. And observance of these laws is mandated under pain of MORTAL SIN. If you break the law, you’ll find yourself in the confessional if you intend to make a Holy Communion.
Now, because of the Latin regulations, many people think that Eastern Catholics have the same sort of things going on. The fact of the matter is that we do not. The closest thing we have is the Eastern Code of Canon Law which says that our Church Sui Juris determines what the fasting disciplines will be. The thing is that our fasting guidelines aren’t something that we modify or make up as time goes on, but something that we’ve inherited from the monastics. This is called the Typikon, and it contains every guideline for liturgy that one would need to know. But the think to keep in mind is that these are just that: guidelines.
They aren’t the ideals, they aren’t the minimums, they are about where we should all aim to find ourselves. Every Byzantine Church, Sui Juris, bases its recommendations off of the Typikon. For instance, in the Ruthenian Catholic Church, there is no penalty of sin for breaking the fasting regulations outside of Lent. However, within Lent, if you break the fasting regulations, you are barred from receiving communion. (The law doesn’t state how long you are barred from the chalice). The Lenten fasting regulations are very simple: no meat or dairy on Clean Monday and Good Friday, no meat of Wednesdays and Fridays. However, we are strongly encouraged to abstain from meat and dairy from the start of Lent until we receive communion at Pascha.
If you look at the fasting regulations throughout the remainder of the year, as far as the Ruthenians go, when it comes to fasting seasons, nothing is imposed. Only for Lent is there extra dietary and penal restrictions enforced. So for the Apostles Fast, the only change you will note is that Tuesday, Thursday, and Fridays are aliturgical – meaning that liturgy is not permitted to be celebrated on these days. The faithful are informed that we are in a fasting season, but we aren’t told what the fast entails. The reason being is that fasting is something voluntary that we should want to take on. And we should try to abide by the norms set forth in the Typikon.
Penance, or rather fasting discipline, varies from person to person. The point is not to become so rigid that the discipline overtakes the spirit. The point is to push ourselves to where it is uncomfortable but not unbearable. We are encouraged to seek the counsel of a spiritual father for a reason.