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Atomic Fasting

Why We Need Clear Rules to Make Habits Stick

Whoever is faithful in small matters will be faithful in large ones.” – Luke 16:10

The popularity of self-help books suggests two things about modern people:

  1. We need help.

  2. No one is coming to help us.

Therefore, we have to help ourselves. Or so we’re told.

It’s true, we are largely free of people telling us what to do. But without discipline, we run the risk of drowning in cheap amusement and distractions. In the extreme, we may even lose or diminish our capacity for joy.

In my last post, I talked about how ancient fasting traditions are making a comeback under new names like “I.F.” (intermittent fasting) and “OMAD” (one meal a day). Similarly, the self-help genre has generated a boom of programs to help us govern our behavior with rules, replacing the religious frameworks that governed the majority of people’s lives up until relatively recently.

Jordan Peterson’s 12 Rules for Life is a quasi-religious text wrapped in the language of secular psychology. James Clear’s Atomic Habits is another example of a best-selling self-help book that has reached millions with wisdom that the ancients have known all along: rules matter.

Clear’s book takes up the age-old question of why we do what we know is bad for us, and how to do a little bit better with a rules-based approach. We are promised remarkable results from tiny changes. The subtitle boasts that the Atomic Habits method provides “An Easy & Proven Way to Build Good Habits & Break Bad Ones.”

Likewise, St. Benedict opens his little rule book with assurances that his suggested disciplines of prayer, fasting, and obedience are easy—the bare minimum, really. Modern psychologists like Roy Baumeister have studied willpower to understand why rules make it easier to abstain from particular activities. More choice, it seems, is taxing. An external authority, such as the Abbot of a monastery, helps to make expectations clear. Enforcement takes away the chore of choosing.

One metaphor for a rule is a box that constricts our freedom. The late Benedictine monk Adalbert de Vogüé, however, selects a different visual:

“Does not every Christian and every religious have a permanent need of a rule that arouses, directs, and supports their efforts as a stake directs and upholds the plant?”

Today, however, there is no stake. No one from the Church is monitoring our behavior or enforcing the rules—especially when it comes to the old fasting rules. Thus we are left to stitch together the tattered remnants of tradition. We can combine this with whatever insights we might gain from the latest psychology to make for ourselves a keepable rule of fasting—in short, a habit.

A rule is a stake that upholds the plant—not a box to constrain freedom.

Towards a Keepable Rule of Fasting

Clear’s core insight is that habits are simply patterns of behavior reinforced by rewards. In his own words, “satisfying consequences tend to be repeated until they become automatic.” Creating good habits first requires clarity about the nature of our bad habits, and an explicit intention to rewire our desires. He says we should start by writing down our current bad habits on a scorecard. Then, we create an easy rule for ourselves to help us habituate a new and improved behavior.

For example: “I will [BEHAVIOR] at [TIME] in [LOCATION].”

We start with the smallest possible incremental changes in behavior. These tiny changes snowball, as you deepen the groove of the new habit through repetition. The key to ensuring repetition is that the new behavior provides some kind of reward.

Here’s where we hit a seeming paradox: fasting is inherently about denying oneself a short-term reward. Long term, we get self-mastery, but it’s uncomfortable to not eat when we’re accustomed to three meals, plus snacks in between.

de Vogüé, in his book To Love Fasting, confronts this paradox head-on:

“The benefits of the fast speak for themselves. It is enough to experience them. But how to obtain this experience? A person does not impose such an effort on himself without being moved by an attraction that is already a kind of love. Thus a vicious circle is established. To love fasting one must experience it, but to experience it, one must love it. The way to get out of this circle is easy: trust in the word of God, in the example of the saints, in the great voice of tradition, and trusting in this witness, try it.”

Self-help books like Atomic Habits confirm what St. Benedict already knew: if we are to fast, we must love it. Like most good habits, fasting eventually becomes its own reward. But if we are to love it, it’s not enough to simply dive in off the deep end and start eating One Meal a Day (OMAD). Most of us can do this for a day or two, such as the prescribed fasting days of Ash Wednesday and Good Friday, but it would be foolish to attempt the transition to Full-on OMAD Monk overnight.

I know, because I’ve tried.


When I first started dabbling in intermittent fasting around 10 years ago, I would wake up each day and attempt to white-knuckle through the hunger. I could make it to dinner time, but only by consuming unhealthy amounts of coffee throughout the day. At dinnertime, the floodgates would open and I would begin to binge from around 6 pm until midnight, and then start the same cycle again the next day. This wasn’t intermitten fasting—it was intermittent gluttony.

In hindsight, it’s obvious what I was missing: 1) a clear rule that imposes a regulated eating window and 2) an incremental approach. Much like late Medieval Trappist monks who set out to eat nothing but rotten food for the 40 days of Lent, I set my discipline too strict and quickly burnt out. Thankfully, I didn’t end up in the infirmary. I did, however, stretch my adrenal glands to the point that I gave up fasting altogether for several years.

In contrast to my all-or-nothing approach, de Vogüé shares his seamless transition to One Meal a Day, which he achieved by gradually postponing his first meal over a long period:

“Gradually, month by month, the first meal of the day became more and more insignificant. One day at the end of two years I suppressed the little that remained and found myself in good shape. With this first liberation attained, I set myself to work on supper in the same way. Progressively, and in about the same length of time, I reduced it to the point where I could do without it. It was not without suspense that you make the final experiment of trying to skip a meal for the first time. One day I did without supper, and saw that all went well. Henceforth I knew that eating only once a day was possible for a modern man like me.”

de Vogüé is the poster child for the Atomic Habits approach of incremental gains. You start with something so small or easy that it’s hard not to succeed, like reducing the size of your breakfast. In wracking up these little wins, we get a taste of the reward that will cement the habit as we attempt increasingly more difficult forms.

In working towards harder habits—such as a longer intermittent fast—you must find the sweet spot between too little progress, which will lead you to stall, and too much, which will lead you to burn out. de Vogüé took two years to make the transition. Many may find that they can adjust more quickly to eating One Meal a Day.

Clear finds evidence that it takes at least 21 days to form a new habit, but the average is closer to 66 days and the range extends all the way up to 200+ days.

40 days falls squarely within that range, making it an appropriate length of time to jumpstart a fasting habit and experience its rewards. However, we should always remember that it is a discipline to be practiced over a lifetime—not a fad diet to be kept for a time, before falling back into the constant snacking and grazing pattern of the modern world.

Without rules or a strong set of principles to conform to, a single slip-up can set us up to give in to a whole chain of temptations. With a rule, we might find that we slip one day, but we can get back on the proverbial horse. Gradual improvement combined with consistency creates the compounding effect that Albert Einstein called the 8th wonder of the world. As Clear writes, never slip two days in a row.

Get weekly resources on recovering the ancient discipline of One Meal a Day fasting:

Designing a Rule for Modern Times

We can recover the ancient fasting tradition by taking baby steps, as both de Vogüé and Clear suggest. The Rule of St. Benedict presents the simplest and best fasting rule: One Meal a Day and limited Lenten abstinence. We should hold this up as the Gold Standard, and lay out weekly stepping stones that will allow us to progress closer to this ideal by the end of the 6-week season of Lent.

Instead of shrinking the size of our breakfast, as de Vogüé did, we will postpone our breakfast and shorten our eating window by a little bit each week. We will also use the traditional fasting days of Wednesdays and Fridays to test our discipline—asking for additional graces on these days to fast for longer than usual—and write out a simple rule to keep ourselves accountable.

Last week, I proposed following the “One Meal a Day” rule on the two traditional fasting days—Wednesday and Friday—to the best of one’s ability, and otherwise simply attempting to fast overnight (12 hours) and abstain from snacking between meals.

No one is going to force you to fast, but if you wish to progress incrementally toward St. Benedict’s original Lenten fasting discipline, here is what I propose for this week’s rule:

  • Week 2 (March 6 - 12) — 13-hour fast, 11-hour eating window.

    • Three meals; no snacking.

    • Wednesdays & Fridays: One Meal (with collations as necessary)

On fasting days, for example, I might consume one cup of bone broth as a “collation,” along with black coffee and tea—but being mindful not to overdo the caffeine, or allow the eating window to continue too late into the evening.

You can download and print the updated template here.

Get the template

In the following installments, we will examine our hunger and cravings to understand how we can rewire our desires to find fulfillment through alternative rewards instead of constant snacking—until fasting becomes habitual. We will review our current eating patterns and aim to replace unhealthy habits with better, more nourishing ones. Each week, if we consistently follow our rule, we can lengthen the fast until we find that eating one meal a day isn’t just easy, but brings us joy as well.

The 50-Mile Man
The Benedict Challenge
Recovering the Lost Discipline of Fasting
Charlie Deist