There is great wisdom in the Christian practice of fasting. Though Christian fasting has been largely abandoned, the one expression of fasting (and penitential practice) that seems to have survived the turmoil of this modern era is that of Lenten penance. Although I suspect it is hanging on by a very thin cultural thread, which will break unless we can make people aware of the great beauty and spiritual significance of these acts.
The forty days of Lent are an ideal period for renewal. Lent is the perfect span of time to form new life-giving habits and abandon old self-destructive habits. But most of us just give up chocolate and when Easter arrives, we are not much further advanced spiritually than we were at the beginning of Lent!
If you wish to have a rich and abundant experience of life, you must allow your soul to soar. But in order to do that, you first need to tame and train the body. You cannot win this war once a week, once a year, or even once a day. From moment to moment, our desires need to be harnessed.
Fasting should be a part of our everyday spirituality. For example, you have a craving for a coke, but you have water or cranberry juice instead – a very small thing. Nobody notices. And yet, by this single action, you say no to the cravings of the body that seek to control you and assert the dominance of the soul. The will is strengthened and the soul is a little freer.
Personalize your fasting. You know what it is that has a grip on you. Friday has always been a traditional day of fasting, and I would encourage you to employ this tradition in your own way. Only you can decide what the right fast is for you.
Try not to be prideful about it. Come humbly to God in prayer, and there in the classroom of silence, decide upon some regular practice of fasting and abstinence.
Fasting is a simple yet powerful way to turn toward God. If there is a question in your life, fast and ask God to lead you. He will. If you have a persistent sin that you just cannot seem to overcome, then fast. Some demons can only be cast out by prayer and fasting together.
Fasting is radically countercultural, but so is Christianity.
Rediscover Catholicism by Matthew Kelly