I hate fasting! I get grumpy, I always feel cold consequently I feel ill, I get headaches and find it difficult to concentrate and consequently I get easily distracted in and from prayer, I crave food (it is psychological, of course but I am sure it gives Satan a chuckle of delight). Normally I can go a couple of days and then remember I haven't eaten but when I fast I am hungry all the time. Far from aiding prayer, I find it a distraction - yes. alright maybe I am not fasting enough, and need to get over the foothills before ascending the mountain.
Saint Thomas Aquinas sums up the Biblical and Patristic tradition and says, "For we fast for three purposes:
(1) to restrain the desires of the flesh;
(2) to raise the mind to contemplate sublime things;
(3) to make satisfaction for our sins."
Well..., again maybe I have never done enough of it. Growing older might well restrain the desires of the flesh but fasting didn't really help, it was a bit like trying not to thinking of Tuesday, it only made Tuesday more obvious and desirable. As for raising the mind to the sublime, it tends to raise my mind to bacon. As for making satisfaction for sin, I can go along with that, except it doesn't feel as though I have made much satisfaction and I end up sinning, at least against charity even more, I think it adds to sloth and then ultimately to gluttony too.
In the West fasting, even the Eucharistic fast has all but disappeared, if you reduce something to a minimum it tends to be a sign of not being important, then of being ignored. Of course Canon Law does present the one hour (quarter of an hour for those over 60) as being the minimum. There is no reason why the pious and virtuous should not fast and abstain from liquids from midnight or even for a few days before receiving Holy Communion.
Fasting for me is an encounter with my own weakness, with my own fragility. This is really what most forms of Christian asceticism are about. They are concerned with embracing weakness, of actually reducing potency, at least in this world, of accepting the real world where Jesus Christ alone is Lord. The obvious example is a virile young man or fecund young woman embracing a life of celibacy, "for the sake of the Kingdom ...", for the sake of Christ 'becoming less'. It is like the the brilliant young theologian or philosopher going off the monastery to look after pigs (or on this Day of the Abdication, the wise and saintly old Pope embracing a life of seclusion and academic silence). 'I will pray for you', is the ultimate statement of our human powerlessness and divine omnipotence. It is end of homo liturgicus,
Although many saints do, it is interesting that Aquinas does not, give fasting as a way of showing solidarity with the poor, or even that most practical sense of saving the money spent on a meal or two in order to give it to the poor. I suspect 'the poor' for Aquinas would be 'the poor Christ'. It is sad that our Bishop's have for so long allowed fasting as being a way of fundraising for aid organisations rather than an ascetic practice that has value in itself, and because Jesus fasted and said his disciples would fast.
Coptic friends boast of fasting for two thirds of the year, they are doing so imitation of those great ascetic saints of the Alexandrian desert there is a sense in which ascetic practice which is difficult or painful give a sense of achievement. An Epiphany dunk in the frozen Volga or laying a lash over the shoulder on a Good Friday (or every Friday) afternoon are easy ways of showing to ourselves our love for God, achieved faster and with more absoluteness than loving a brother with whom one has nothing in common, in the same way as putting a heavy cross around our neck or being tattooed with one, is easier than carrying one and following Christ.
Fasting is an expression of the incarnational nature of of our faith, we are not Manichees, we have bodies, we should use them. Conforming our bodies to Christ, at least in theory conforms our souls or our minds to him.
So this Lent do some physical penance: endure the cold, keep vigil in the night, walk barefoot over sharp rocks, kneel or prostrate on a damp stone floor, wear sackcloth, use the discipline or celice often. The trouble with these is that they can so often be vainglorious, more about our endurance of pain, more about me - fasting on the other-hand is less likely to us physical or spiritual harm, so fast! Even if it is difficult and the good it does is difficult perceive, do it.