So are you saying that one can't partake of the Eucharist unless one has kept the fast all morning? (I'm not Orthodox - yet!) Yikes! I get extremely faint and dizzy when I don't eat breakfast.
That's the standard: The Eucharistic fast starts at midnight the night before, if liturgy is served in the morning, or for an evening liturgy, such as presanctified, the fast starts at noon. If you have health problems, need to take meds with food, hypoglycemia (dizziness and fainting), etc, you talk with your priest and get permission to take care of your physical needs. If the fasting will keep you from driving safely, you eat something so that you don't crash your car, etc. The point is to do it under the direction of your priest, and don't go making up excuses for yourself by yourself.
For years I had permission to eat something before liturgy. Then I went to a service of holy unction (healing service) last Nativity Fast, and since then, I've been able to fast for the most part. God did it! Wow! But it's still hard. I certainly did not go to that healing service expecting the ability to fast to be the result.
Part of it is a learning process. I think many Orthodox know that it's a smart idea to have a late night bowl of chili or some other high protein food on Saturday night, and a BIG glass of water so that one does not start the fast ravenously hungry and thirsty. (During lent I make fishstix for the kids and that tides them over fairly well.) Avoiding sugar or alcohol the night before fasting also makes it easier. And of course prayer...don't forget prayer.
Physical Hunger becomes a reminder of, an icon for, our very real spiritual poverty and we approach Christ empty...always empty...so that He fills us with Himself. If our view of personhood, one's spirituality and physicality, is holistic, how can it be any other way? What is going on spiritually is so very intertwined with our physical bodies that the two cannot be separated. At least this is the eastern view. This is why we do "body prayers" called reverences, great prostrations, and the sign of the cross. We do not hold a dualism between the spiritual and the physical. Fasting is not a form of self-punishment, but rather a tool four our healing, so that we learn how much the saying "their god is their stomach" applies to us so that we can repent.
There are numerous documents of the early Christian Church that document the fasting practices of that time. I remember in Seminary thinking: "Wow, such asceticism! How much have we lost!" Well, physiologically the human being has not changed a bit in 2000 years, and neither has our spiritual condition changed. What was good medicine then is still good medicine now. What was possible then is still possible now. And the Orthodox Church has been trundling along doing the exact same fasting that it's always done, for 2000 years. And it's still just as hard now as it was then, and still just as worth it. Speaking personally, it brings me down to the depths of myself, and I am more aware of where I need the grace of God. I wake up in the morning, and I say to myself: "This day, I will do this." And it really is one day at a time, to get trough a time like Great and Holy Lent. And I probably talk about it too much. I probably ought to just shut up about it, both on this blog and in real life, but I've never been good at the being quiet part. I tend to talk about everything. So my non-Orthodox friends know all about it. Sigh. It would be better to quietly skip the brownies or the chocolates or the sausage gravy, than to have people watching me skipping the brownies, milk chocolates or sausage gravies, or watching me nab a cookie that most likely had butter in it. But that's part of the point, that fasting pulls us to the point grace where we know, without a doubt that we cannot save ourselves but must rely wholly on the grace of Christ. That's what keeping the fast is ultimately about.
I should add this end note: Fasting, in the Orthodox tradition, is not a total abstinence from food except for the Eucharistic fasts, which last less than a day. We definitely down-shift, and fast from Meat, dairy, eggs, olive oil and wine (alcohol), but are permitted shrimp, shellfish and insects(and many American Orthodox include cheapo fish like fishsticks and tuna in this category, with the blessing of their priests because it's SILLY to spend twelve bucks a pound on Lobster just because its technically a big ol' bug and wasn't considered high eating by the ancients.) and of course all the vegan goodies such as bread, fruit, nuts, legumes, vegetables.
Forgive me, a sinner. I'm writing this on an empty stomach and I hope I have not mis-spoken in any way.