How often should we be fasting?

zcihjdhyo6ieevshlnkgAs we being the season of Lent, traditionally a period of discipline and denial, the subject of fasting naturally comes up. But before we think about fasting for ourselves, we need to ask: How often did Jesus and the first generation of his followers fast? Was it an occasional thing, focused on specific events or causes? Or was it something more habitual and regular, an integral part of their devotional life?

As most studies of the subject point out, fasting in the Old Testament was associated either with particular festivals (such as the Day of Atonement), with particularly intense experiences (as with Moses spending 40 days in the presence of God on Mount Sinai, echoed by Jesus’ fast in the desert which gives us the season of Lent), or with special seasons or feelings. Typically in the prophets and the writings, fasting is associated either with grieving, repentance, or intense prayer for a particular cause. There is nothing in any of these references to suggest that fasting was a habitual part of regular devotional activity.

But there are some fascinating clues to a change of perspective in the (so-called) inter-testamental period. The Book of Tobit relates stories set in the eighth century BC, but most believe it was written in the mid-second century BC (most scholars date the book of Daniel to a similar period).

Tobit 12.8–10 records the teaching of an angel as follows (in the style of sayings from Wisdom literature):

Prayer is good when accompanied by fasting, almsgiving, and righteousness. A little with righteousness is better than much with wrongdoing. It is better to give alms than to treasure up gold.

For almsgiving delivers from death, and it will purge away every sin. Those who perform deeds of charity and of righteousness will have fulness of life;

but those who commit sin are the enemies of their own lives.

What is striking here, in relation to the earlier Old Testament texts, is that fasting has now become a regular part of devotional activity. What is even more striking is the close relationship between the practices in this text and Jesus’ teaching in Matt 6.1–18:

Be careful not to do your ‘acts of righteousness’ in front of others, to be seen by them… So when you give to the needy, do not announce it with trumpets… And when you pray, do not be like the hypocrites… When you fast, do not look somber as the hypocrites do…

Here we have the same cluster of concerns—of righteousness, prayer, almsgiving, and fasting. And, once again, fasting is assumed to be a regular, habitual part of the devotional life, not something reserved for special occasions. This also fits with the question that is asked of Jesus and his disciples: ‘How is it that John’s disciples and the disciples of the Pharisees are fasting, but yours are not?’ (Mark 2.18). The TNIV has translated this in a way suggesting this was a continual practice—and for good reason. In the parallel in Luke 5.33, the question appears to be on the lips of Jesus’ critics who state: ‘John’s disciples often [Gk: pukna, frequently] fast and pray, and so do the disciples of the Pharisees, but yours go on eating and drinking.’ Matthew appears to be caught between Mark and Luke. Whilst most manuscripts have at Matt 9.14 John’s disciples asking the question ‘How is it that we and the Pharisees fast…?’, a minority tradition has added the word ‘often’ [Gk polla], probably in an attempt to harmonise Matthew with Luke.

DidacheIn fact, Luke appears to have a particular interest in this regular habit. In Jesus’ story of the Pharisee and the tax collector in Luke 18, we hear the Pharisee proclaim, ‘I fast twice a week…’ (Luke 18.12), and in fact we know on which days he fasted! An early Christian teaching document, the Didache (usually dated to the late first century, but lost until its rediscovery in the 19th) says this:

Chapter 8: But let not your fasts be with the hypocrites, for they fast on the second and fifth day of the week. Rather, fast on the fourth day and the Preparation (Friday). Do not pray like the hypocrites, but rather as the Lord commanded in his Gospel, like this:…

and then follows a version of the Lord’s prayer very similar to the one we find in Matthew (‘his Gospel’). (For more on this, see the post on Jesus’ poetic teaching.) The term ‘hypocrites’ most likely refers to Jews who do not follow Jesus (hence almost certainly dating the Didache to some time after the year 85) but who fast—guess what!—on two days a week, Mondays and Thursdays. And precisely in line with Jesus teaching in all three Synoptic gospels, the followers of Jesus are also expected to fast two days a week, albeit on different days. In one of Luke’s other references to this practice, Acts 13.2, again it appears to be a habitual practice of the community of believers. (There is evidence that this regular fasting went from after breakfast until a light evening meal, rather than being a 24-hour period without food.)

Further confirmation of this practice comes from a slightly unlikely source. In Rabbinic Judaism from the second century onwards, there is no evidence that fasting continued to be a habitual practice. Instead, patterns of fasting return to what we find in the Old Testament. The best historical explanation of this is the mirror of what we find in the Didache. Just as the early Jewish followers of Jesus began to define themselves over against mainstream Judaism, so Rabbinical Judaism then began to define itself against the growing Jesus movement. So a practice like regular fasting, which marked out Jesus-followers against their pagan context, would be a good thing to drop.

Finally, it’s worth reflecting on what this habit of fasting two days a week signified as a devotional practice. As Eliezer Diamond notes (Holy Men and Hunger Artists, p 130) the idea of regular fasting would have seemed odd to most in Graeco-Roman culture. The majority would have seen no need for it, whilst certain ascetic groups did practice fasting, but as a sign of detachment from the world. Intermittent fasting says something different.

‘Feast’ days celebrated a world made by God and all the good in it; alongside this, ‘fast’ days signified repentance, mourning and longing for deliverance—just the sort of practice you might adopt if you were awaiting the deliverance of a Messiah and the breaking in of the age to come. Intermittent fasting is just the sort of thing you might continue to practice if you wanted to continue to both affirm the world you lived in, but also to look for an age to come; it is the dietary expression of the ‘now and not yet’ of the kingdom of God (or, to use a theological term, the ‘partially realised eschatology’) we find in the New Testament. This is reflected in Jesus’ response to the critics of him and his disciples:

Jesus answered, “Can you make the friends of the bridegroom fast while he is with them? But the time will come when the bridegroom will be taken from them; in those days they will fast.” (Luke 5.34–35)

Jesus is pointing out that, as we live in this world but look for the age to come in Jesus’ return, we are in the same position as those in his time who were expecting the Messiah to deliver Israel. So fasting is just the thing you would do if you were in the habit of praying ‘Your name be hallowed, your kingdom come, your will be done, on earth as it is in heaven’!

So the question worth asking is: why wouldn’t we do the same now? This shouldn’t just be a Lenten discipline, but part of our regular devotional habit. Perhaps Lent might be a good time to start?


(In a wonderful piece of synchronicity, Michael Mosley advocates, on health grounds, intermittent fasting on…Mondays and Thursdays!). (Earlier versions of this piece were published in 2013 and 2016.)

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8 thoughts on “How often should we be fasting?”

  1. Wesley promoted Wednesday and Friday fasting (is this coincidence if the Didache was still lost at that point?). See

    ‘For a portion of John Wesley’s ministry, he advocated fasting on both Wednesday and Friday each week as a regular spiritual discipline. It’s fairly well known that Wesley would not ordain anyone to the Methodist ministry who was unwilling to fast those days.

    But as time passed, Wesley fasted mostly on Fridays, which was the Anglican norm. (Actually, as early as August 1739, he advocated Friday fasting for Methodists in his journal, according to the Anglican rule.)

    Wesley usually began a Friday fast at sundown on Thursday. This was in continuity with Jewish and early Christian tradition, which both marked the beginning of the day at sundown, not midnight. Wesley typically ended his fast at 3:00 p.m. on Friday.’

    • That’s an interesting observation. I suspect that Wesley picked up the tradition which had lasted in the Church (hence the RC practice of fish on Fridays, a fast from meat) but originated in the practice to which the Didache testifies.

  2. Takes me back to a book read in my earlier Christian days: God’s Chosen Fast by Arthur Wallis. Not read it since, though it was influential on intensity in spiritual warfare and prayer at that time in Charismatic circles.
    I also recall an emphasis on fasting in Rees Howells : Intercessor by Norman Grubb. Again not read it from earlier days.
    I’ve barely heard a whisper about fasting for many a year. Not sure how fasting is regarded in Reformed circles.
    But, we break-fast each day, even if it is earlier than Wesley’s 3.00pm.

    • Yes. Interestingly, the 16/8 fasting regime is nearer to Wesley’s practice, advocation leaving 16 hours between two meals. So if you eat at 6 pm (i.e. sundown), then you should not eat again until 10 am.

  3. Thanks Ian for this thought-provoking post. As a younger man, planting a new church in a very challenging context, I fasted without fail one full day a week and witnessed many a breakthrough that I feel sure were related to the greater intensity in prayer that fasting can bring. Life is rather more comfortable these days and I fast much less now; I feel convicted about that. A good thing in these early days of Lent.

  4. Is fasting compatible with a secular vocation? If a person fasting drives a car, van or lorry, or works as a dentist or a surgeon, most members of the public – if they are sharing the road, and especially if they are the patients – earnestly hope that the faster’s blood-sugar levels, and consequent alertness, are at maximum. This question is relevant to fasting undertaken as an observance of any faith, whether Christian, Muslim or other.

    • ‘earnestly hope that the faster’s blood-sugar levels, and consequent alertness, are at maximum’

      As I think I mention, Michael Mosely’s research suggests that they are…


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