“Those pursuing the spiritual way should train themselves to hate all uncontrolled desires until this hatred becomes habitual. With regard to self-control in eating, we must never feel loathing for any kind of food, for to do so is abominable and utterly demonic. It is emphatically not because any kind of food is bad in itself that we refrain from it. But by not eating too much or too richly we can to some extent keep in check the excitable parts of our body.
In addition, we can give to the poor what remains over, for this is the mark of sincere love. It is in no way contrary to the principles of true knowledge to eat and drink from all that is set before you, giving thanks to God; for ‘everything is very good’ (cf. Gen. 1:31). But gladly to abstain from eating too pleasurably or too much shows greater discrimination and understanding. However, we shall not gladly detach ourselves from the pleasures of this life unless we have fully and consciously tasted the sweetness of God.
[…] Fasting, while of value in itself, is not something to boast of in front of God, for it is simply a tool for training those who desire self-restraint. The ascetic should not feel proud because he fasts; but with faith in God he should think only of reaching his goal. For no artist ever boasts that his accomplishment is simply due to his tools; but he waits for the work itself to give proof of his skill.” (St. Diadochos of Photiki in The Philokalia: The Complete Text, Vol. 1, pp 266-267)