Why Don't You Fast?

The Prophets Fasted:

Moses: When I went up into the mountain to receive the tables of stone...I was in the mountain forty days and forty nights, I ate no bread and drank no water. Deuteronomy 9:9 (LXX)

Prophet Jonah:  It was by fasting among other things that the people of Nineveh were saved from his prediction of peril.  Jonah 3:7  (LXX)

Prophet Joel: Fasting associated with repentance:
“Now, says the Lord your God, turn to Me with all your heart, with fasting and with wailing, and with mourning. Joel 2:12 (LXX)

Prophet Daniel: Fasting with repentance and prayer are an aid in seeking God and the spiritual life:
And I set my face toward the Lord God, to seek him diligently by prayer and supplication, with fastings and sackcloth.  And I Prayed to the Lord my God, and confessed...  Daniel 9:3-4 (LXX)

Jesus Fasted:

Immediately after His Baptism, what did He do?

And when he had fasted forty days and forty nights,
he was afterward hungry. 

What was His instruction for Apostles in the case of the epileptic boy whose demon the Apostles could not cast out?

This kind does not go out except by prayer and fasting.

When challenged by Pharisees about His disciples what did He say? 

Can the children of the bride chamber mourn, as long as the bridegroom is with them? But the days will come, when the bridegroom shall be taken from them, and then shall they fast. 

The Lord Himself gave instructions for fasting:

But you, when you fast, anoint your head, and wash your face; That you appear not unto men to fast, but unto your Father which is in secret. Matthew. 6:17-18

Why did he say this?

Apostles fasted:

In the Acts of the Apostles we read:
As they ministered (liturgical rite) to the Lord, and fasted, the Holy Spirit said, Separate me Barnabas and Saul for the work whereunto I have called them. And when they had fasted and prayed, and laid their hands on them, they sent them away.

They coupled fasting with liturgical acts

Paul: Apostle Paul describes his own spiritual life as one of sacrifice, vigils, thirst, and fasting lived “in weariness and painfulness, in watchings often, in hunger and thirst, in fastings often, in cold and nakedness.”

He also refers to fasting in the context of marriage saying that by mutual consent husband and wife abstain from marital relations periodically while fasting and prayer.

The first century - Didache
“The Teaching of the Twelve Apostles” 

Your fasts must not be identical with those of the hypocrites. They fast on Mondays and Thursdays; but you should fast on Wednesdays and Fridays. 

The fasting referred to here was a complete abstention from both food and drink until sundown. 

Church Fathers fasted.

Ecclesiastical writer Tertullian (220 d.) notes that spiritual growth requires confession and prayer fed by “fasting, ...not for the stomach’s sake, ...but for the soul’s.

Saint Gregory (391) - practice of receiving the Eucharist after fasting.

Saint Basil (379) wrote much on fasting.

John Cassian (435): Therefore, fastings, vigils, meditation on the Scriptures, self-denial, and the abnegation of all possessions are not perfection, but aids to perfection: because the end of that science does not lie in these, but
by means of these we arrive at the end. 

Saint Athanasius (373) - Fasting more than just food.
...let us vie with each other in observing the purity of the fast by watchfulness in prayers, by study of the Scriptures, by distributing to the poor, and let us be at peace with our enemies. Let us bind up those who are scattered abroad, banish pride, and return to lowliness of mind, being at peace with all men, and urging the brethren unto love. Letter XIV.

Saint Athanasius describes the benefits of fasting.
It “...cures ills and dries up bodily humors, casts out demons and turns away evil thoughts; it makes the mind brighter, the heart clean, and the body holy; and it presents man before the Throne of God.”

Modern Saints Fasted

Saint Nectarios of Aegina (1920)Fasting is an ordinance of the church, obliging the Christian to observe it on specific days.  ...He who fasts for the uplifting of his mind and heart towards God shall be rewarded by God, Who is a most liberal bestower of divine gifts, for his devotion.  
...unless one lifts his mind and heart towards God through Christian--not Pharisaic--fasting and through prayer, he cannot attain a consciousness of his sinful state and earnestly seek the forgiveness of sins.. Prayer and fasting--Christian fasting-- serve as means of self-study, of discernment of our true moral state, of an accurate estimation of our sins and of a knowledge of their true character.
(Vol 7 of Modern Orthodox Saints, 2nd ed., p 178)

The purpose of fasting is chiefly spiritual: to provide an opportunity and preparation for spiritual works of prayer and meditation on the Divine through the complete abstinence from food, or the eating of uncooked food or frugal fare. 
However, fasting is no less valuable for physical health, since self-control and simplicity of life are necessary conditions of health and longevity, as dietetics tells us.

Canons of Church require fasting

If you do not honor the Wednesday and Friday fast you are to be excommunicated.

Must fast prior to taking Communion

Strict fast during entire Lenten period

Do not fast on Sunday and Saturday

If ill or weak relaxation of guidelines appropriate

Always been essential part of Orthodox Christian Life. 

Necessary discipline to combat the passions and open the door to the renewal of the Holy Spirit. 

Why don’t you fast?

Fasting foods should be simple and plain and not extravagant. 

The more effort that goes into their creativity and preparation, the more its value is reduced. 

Should not be prepared to satisfy our craving for certain tastes       
   •  Break from our automatic response to food,
   •  Give thanks to the provider, out Lord,
   •  Increase our self-control.