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Day 2: Creating a Keepable Rule of Fasting

St. Benedict Had a Rule and You Should Too

Charlie Deist
5 min readMay 6, 2022


I emphasize the importance of adhering to a keepable fasting rule — finding a sustainable rhythm that you can increase or modify over time. It may be tempting to go full-on “Jesus in the Wilderness” from Day 1, but wisdom requires knowing your limits.

You don’t want to stress yourself to the breaking point — like certain monastic orders of the Middle Ages did — and exit your safe “hormetic zone.” Past a certain threshold, the negative stress of fasting can outweigh the beneficial “hormetic” stress. There is also a risk of succumbing to spiritual pride if you set your aims too high, and puff yourself up for achieving them.

We won’t get back to the relatively strict fasting requirements spelled out in the Rule of St. Benedict overnight. Benedictine monks ate just one meal a day throughout Lent, with many additional restrictions on what they were allowed to eat. However, if we’re consistent and earnest in our desires, we can get to that point eventually.

“It may be tempting to go full-on ‘Jesus in the Wilderness’ from Day 1, but wisdom requires knowing your limits.”

Picking a Fasting Protocol: One Meal a Day, 16:8, or “Fast Five”?

Having a rule gives you a clear intention and kind of external authority so you don’t need to rely so much on your own discretionary willpower. You commit to the rule, write it down, and then it’s decided. There’s no question mark.

You can always adjust your rule week-by-week based on feedback from your body.

Feeling frazzled and burnt out, like you’ve had too much coffee? It may be time to scale it back.

Feeling lethargic, sluggish, or overfed? Maybe you could stand to increase the intensity a bit more and fast for longer.

The key to finding a good rhythm is to set a consistent and keepable habit with some variation and flexibility. As a baseline, I suggest committing to the minimum viable fast of 12 hours each day, followed by an eating window of 12 hours. That allows for three meals, with no snacking between. This will take you out of grazing mode — absent-minded eating. If you can just stop eating late at night or first thing in the morning, you’re already giving the body time to rest and digest, and building a foundation for longer fasts like:

16:8 (16 hours of fasting, then eating 2 meals in an eight-hour window)

“Fast Five” (eating within a five-hour window), and finally…

“OMAD,” or One-Meal-A-Day: fasting for 22 to 23 hours a day, and eating in just a one or two-hour window.

“The key to finding a good rhythm is to set a consistent and keepable habit with some variation and flexibility.”

You can further clarify your intentions by scheduling meal times, and even specific meals.

Introducing Variations like Keto to Supercharge your “Fatburn”

Once you have a week or two of 12:12 under your belt, pick a couple of days per week to experiment with a longer fast, and consider adding some strategic abstinences. I fast on Wednesdays and Fridays, per Catholic tradition, and also abstain from meat on Fridays.

The original “Benedict Challenge” called for abstinence from four-legged animals (beef, pork, lamb, etc.), and all meat on certain days, plus dairy, and even certain oils. Without going overboard, you can consider adding different restrictions. If your aim is weight loss and a metabolic shift toward “fat-burning,” I recommend preceding your longer fasts with at least one day of a high-fat, very-low-carb, aka the ketogenic diet, to prime yourself to consume your own body fat during the fast.

At the very least, you should start to eat a lower-carb breakfast, so as not to spike your insulin when the body is most sensitive. Alternatively, you can spike your morning coffee with heavy cream for breakfast, which is like fasting until lunchtime but without as much hunger.

On weekends, I usually allow myself more flexibility, knowing that plans with family and friends make it harder to stick to a rigid rule. As a social grace and common courtesy you might eat whatever is served if you’re having dinner at someone else’s house. The one exception to this is if you suspect you may have some food sensitivities, I recommend taking these 40 days as an opportunity to try eliminating the likely culprits (grains, legumes, dairy, and processed foods), and stick to meat and some vegetables. If you then “cheat” on the weekends, you won’t get the break your body needs to identify your undiagnosed allergies as you start to add them back in.

Finally, in the spirit of self-denial, specify in your rule whether you want to give up alcohol, caffeine, or any other little vices that you may be overusing. Perhaps you can give yourself an allowance like “one cup of coffee before noon” on weekdays, or “a glass of wine with dinner on Sunday.” Personally, I allow myself a splash of lemon or grapefruit juice in water on fasting days.

Don’t make your rule too hard to keep, or too complicated.

Some other possibilities for untraditional fasting might include fasting from negative thoughts, or giving up dessert, but the main idea is that fasting itself is its own discipline. There’s no need to complicate it. Your entire rule should fit on a piece of paper, and be easy enough to commit to memory. The written rule is more of a contract with your future self than a reminder.

You are trying to anticipate exceptions and incorporate them into your rule in advance so that you can still keep it. However, if you do break the rule, don’t beat yourself up about it. All is not lost just because you ate a snack between meals. Just get back on the horse and start up again.

Finally, while not strictly necessary, I recommend committing to a prayer or meditation practice — even if it’s only 2 minutes in the morning, or in the evening, or both. Just like with fasting, you want to start small and work up to longer sessions, building on the little “wins” to establish a firm habit. Prayer and fasting reinforce each other. Be sure that you’re pushing yourself just enough but not too much.

If you want to download the actual template I use to write my rule, sign up for the Benedict Challenge here.

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Charlie Deist