Abba John the Short said: “If a king wants to take a city whose citizens are hostile, he first captures the food and water of the inhabitants of the city, and when they are starving subdues them. So it is with gluttony. If a man is earnest in fasting and hunger, the enemies which trouble his soul will grow weak.”

~ Sayings of the Desert Fathers, 4.19

Evagrios calls gluttony one of three “frontline demons.” Here Abba John the Short uses military imagery as well, except he highlights the proper countermeasure that we ought to take against this frontline enemy: fasting.

But what is fasting? I’ve written about it before, but I don’t think I’ve written any sort of introduction. Furthermore, it seems to me that fasting has had too little theoretical analysis in general. That is, before examining how fasting works, it is worthwhile to ask: what is fasting per se?

Before answering this basic question, I think an even more basic one is necessary: what is eating? The question might sound stupid and the answer might seem obvious, but lets start here.

Kelly and I attended an all-you-can eat buffet for a lunch seminar today. I don’t know if I’m in principle against the idea; feasting is part of Christian spiritual practice as well. But in any case it led me to reflect on eating.

We eat to sustain our lives. This, perhaps, is why fasting may sound so strange to the irreligious. We have hunger to tell us to eat in order that we can survive. What’s wrong with that? Does fasting require a spirit/matter dualism?

Well, there’s nothing wrong with that really. It’s true so far as it goes. But how far does it go?

“Man does not live on bread alone,” says Deuteronomy, “but on every word that comes from the mouth of God.” Food only keeps us living, but it is not the ultimate source of our life.

Remember in grade school when you learned about the water cycle and the predator/prey cycle, photosynthesis, and all that? Well, what should have been obvious occurred to me today: every animal sustains its life through the death of other living things. In eating, we sustain our material life at the cost of the material death of other living creatures, plant and animal.

In this light, we may define fasting as follows: fasting is the minimization of the external death required to sustain one’s life through the internalization and overcoming of death. Fasting spiritualizes the death required to sustain our lives, transfiguring that death into new life. Fasting pours scorn upon our fear of death. Fasting is faith in the resurrection.

When we fast, we deny our most basic survival instinct, not because material life is bad—it isn’t—but because spiritual life is better. Indeed, fasting unites the spiritual and the material; bodily discipline of this kind strengthens the soul. It is a positive good, though only as a result of a process—asceticism—that contains a negative aspect: self-denial.

Thus, fasting may be the most basic means we have of self-denial. No wonder the fathers place such a high value on it: all other self-denial grows from this root. 2 Clement, an early Christian sermon, even says that fasting is the power of prayer. The negative corollary to that—though a bit of an exaggeration—is that prayer without fasting is impotent.

Naturalistically, Vladimir Solovyov points out how different fasting rules are rooted in the hierarchy of creatures in the world. Our lightest fast cuts out meat and poultry, but still allows for fish. Fish are cold-blooded and insensate to pain. Thus, from a food ethics point of view (which is not the main point of fasting), preferring fish to meat is more compassionate.

A vegetarian diet is a refusal, if only for a day, to live off the death of another sentient being. A vegan diet refuses even to take that which nourishes their young (milk) or the promise of that youth itself (eggs).

We also fast from alcohol at times, which shows the limits of this sort of analysis. But we can relate it to the idea of celebration, “living life to the fullest.” As I said, there is a time for feasting, but not every day is a feast. Indeed, fasting makes every feast that much better. With dozens of Christmas parties during Advent (when we should be fasting) before the twelve days of Christmas (the time we traditionally ought to celebrate), they become more the calm after a storm of feasting and busyness, rather than the time when we take a break from our discipline to feast and relax.

One last thought about hunger: notice that Abba John calls hunger an ally against our “enemies” (temptation, sin, vice). This is perhaps the strangest thing about fasting. Every Lent, I find that by the end, though excited for Pascha, I also am sad to see the fast go. Hunger, given for material survival, is transformed through fasting to a constant reminder to pray and keep watch on my thoughts and passions for anything that would lead me into temptation.

Hunger is certainly an evil to the starving, but to the person who can indulge in the luxury of fasting, hunger becomes a faithful friend. Jesus even says in the Gospel according to St. Luke: “Blessed are you who hunger now, for you shall be filled.” Similarly, St. Matthew records Jesus’s fourth beatitude as “blessed are you who hunger and thirst for righteousness, for you shall be filled.” Hunger has a higher calling than mere bread.

Indeed, this, according to St. John Cassian, was the only consistent rule of fasting held among the desert fathers: after every meal, always leave a little hunger. “If a man is earnest in fasting and hunger, the enemies which trouble his soul will grow weak.” The bodily weakness of hunger is a spiritual strength. And here, too, the words of the Lord to St. Paul hold true: “My power is made perfect in weakness.”