I’m an Eastern Orthodox Christian. So we have lots of fasting around the year but that doesn’t mean we always observe it, it is expected and encouraged though.
Every Wednesday/Friday is supposed to be no meat/dairy/egg with a few exceptions around the year for example the week after Easter as it is a happy week.
Then we also have four important fasting periods in the year. The lent for Christmas, starting from 15/11, the Lent in August from 1/8 till 15/8 day for the Dormition of the Mother of God, a small Lent sometimes in June for the Holy Apostles and of course the Lent for Easter which is the longest of all, lasting seven weeks.
It was established when all Christians were the same in the 4th century AD. Afterwards the Catholics went their way, did their own thing and later the Protestants etc.
Anyway the Great Lent for Easter it’s the strictest normally is no meat/egg/dairy/oil and wine (generally no alcohol) between Monday to Friday for the last five weeks (the first 3 it’s a gradual introduction to that) During weekends oil and alcohol are allowed. The beginning of the strict part is on a Monday called “Clean Monday”, this year was on 10/3 . (Note: not all Christian Orthodox are using the Julian calendar but some churches like the Church of Greece, Cyprus, Romania etc use the revised Julian calendar which is like the Gregorian)
What I didn’t know even I’ve been an Orthodox Christian all my life is that in the past and still some very obedient Orthodox Christians on Clean Monday till Clean Wednesday (so 3 days in a row) would have no food and no water if they could and then they would have Holy Eucharist on Thursday and continue with the strict fasting.
Most Orthodox can’t or do not want to try to fast all these days per year or they do something that suits them for example at least no meat during the whole Lent. Many people try though to fast during the last week -the Great week. Starting from Monday till Saturday night even if they receive Holy Communion for example on Great Saturday, the fast has to end after the midnight on the Easter Sunday (early hours).
When I was little I fasted once very strict so completely vegan from Monday to Easter Sunday after the midnight. We had pasta in tomato sauce, bean or lentil soups with no oil, fruit , bread with honey or tahini, salads no olive, boiled potatoes etc. It was very difficult but I remember a nice feeling in the end and how much more excitement I had for the Easter meal and all the other Easter delicacies.
I’m a breastfeeding mum for years and can’t fast but also aware I’m not trying enough. This year I will try to go vegan during the Great week but can’t not even use a sort of oil to cook my food like olive oil or sunflower oil. Lots of people do what I’m describing and try maybe at least the no oil day to be the Great Friday.
As I said it’s expected or encouraged and everyone can discuss his situation with his spiritual father, especially if he would like to receive Holy Communion.
Strictly speaking there’s also advice on giving up on various other things too like smoking or sex, you’re not supposed to get full on vegan food just because it’s vegan even if it’s “allowed” so basically fight your own “passions” especially if you intend to receive Holy Communion or at least in the Great week where it’s the “Week of the Passions of Christ”.