This is the 12 week protocol I often use in practice to build up someone’s tolerance to fasting.
For the newbies who have never fasted before, let me first offer my congratulations.
You are about to embark on a journey that honours your biology, takes back your power, and to not be bludgeoned by the food industry, and their constant demands that you are eating at all times.
For seasoned fasters who are ready to take the next jump… hang tight, this article is also designed for you.
I will walk you through how to build up tolerance, disrupt hunger signals, and work your way up to a longer term fast with the strategies you need to be successful.
As a disclaimer, please keep in mind these are general protocols.
I have designed them to slowly allow for habituation to fasting.
This protocol is not specific to any type of individual.
With longer term fasting, I always recommend working with a health care provider who can tailor this protocol to your specific needs.
NOTE: This article is 2,835 words. If you want the simple supplementary checklist and Quickstart Guide to Fasting as a PDF download, get it right here. It’s free.
If you are curious about the benefits of fasting, and why you should be doing it, read this first.
One of the things I love most about fasting is it is unbiased and non denominational.
No matter what you’re diet, your philosophy on food, or your upbringing, you can still incorporate fasting into your way of eating.
So, you’re Keto? You can still fast.
Paleo? You can still fast.
Pescitarian? You can still fast.
Vegetarian? You can still fast.
Vegan? You can still fast.
Pegan? You can still fast.
Fasting is flexible, and will complement any style of eating you choose, while amplifying your weight loss efforts, and enhancing your metabolic fitness.
There is something incredibly powerful about taking control of your hunger, and not being a slave to cravings.
You will learn through fasting, that you do not need external things to satisfy you, and that you can break your hunger patterns.
Which, in and of itself is liberating and empowering.
From our history, we have hardwired pathways and protective mechanisms that happen during fasting.
I would go so far as to suggest that we have 2 main “programs” we run on when it comes to food:
- A Fasted program
- A Refeed program
Both are hardwired, with predictable, consistent changes when we practice both.
Weeks 1–2: Time Restricted Eating aka “Intermittent Fasting”
“Fasting is the first principle of medicine; fast and see the strength of the spirit reveal itself.” — Rumi
If you are completely new to fasting, I will usually recommend experimenting with what is commonly referred to as time restricted eating.
This terms was coined by Dr. Sachin Panda and it refers to the hours in which you can eat.
An easy, dip-your-toes regimen starts with a 12 hour time restricted eating window.
Meaning, you must eat your food within 12 hours.
So, a 12 hour time restricted eating window would be 7am- 7pm.
Or it can be 8am-8pm.
You get the picture. Basically, pick any 12 hour window and eat within that time frame.
So if you have your first bite of food in the morning at 7am, you should aim to consume all your calories before 7pm.
And before you ask, that includes everything.
Yes, it includes coffee.
This will allow for a complimentary 12 hour fast.
This is the most basic introduction to the dance between fasting and refeeding.
In all forms of fasting, be it short or long term, there are aspects of repair and rejuvenation on a cellular level that are integral to health span and lifespan.
This should be practiced and mastered for 14 days (2 weeks) straight before moving on to the next step.
Weeks 3–4: Time Restricted Eating With A Night Limiter
“Instead of piling up food in my fridge that says ‘Come eat me!’ I keep enough for only a couple of days. And I rarely have treats around that might tempt me late at night, which is when I usually crave something really fattening. What am I going to do? Drive out at 11 at night just to satisfy a craving? No, that’s crazy.” — Jennifer Love Hewitt
Once you have mastered the 12 hour fast and refeed rhythm, the next step is to coordinate your eating so that you finish your food 3 hours before bed time.
This is primarily because we want the stomach to fully empty so as to sync up and optimize our sleep and wake cycles, known as our circadian rhythms.
We have all had the experience of eating late, having crazy dreams, and poor quality of sleep. Not to mention the acid reflux, and feeling like a bag of potatoes the next day.
For better sleep, check out this article for ways to hack into better sleep.
We are creatures of habit, and we maintain those habits via circadian rhythms.
It is the communication between the various clocks in our body and our master clock in the brain helps regulate our natural sleep and wake cycles.
The master clock in our brain is called the Suprachiasmatic Nucleus (SCN).
It is a small little nucleus in our brain that is sensitive to light, and is the master coordinator of our wake and sleep cycles.
This small nucleus in the brain syncs your sleepyness and wakefulness with light that comes through the retina.
Then it coordinates with other, body-clocks (like the liver for example) using neural or hormonal signals, core body temperature, or eating and fasting cues.
You can begin to see how late-night computer/device use, snacking, and large dinners throw off our internal clocks — both in the brain and the body.
Let’s walk through a common North American evening with our internal clocks in mind.
Outside, the sky begins to darken. The SCN detects this and starts the process of preparing the body for sleep.
But then…our largest consumption of energy — dinner — takes place. The liver, a clock in the body, receives information that fuel (for movement, and energy) is at its highest.
And just like that, we are out of sync.
Continuing this example, after dinner, we sit and watch TV (or browse social media on our devices), increasing the amount of light and stimulation reaching our central clock in the brain. This confuses the brain and inhibits the natural release of melatonin, a hormone that promotes and regulates sleep.
Or perhaps we skip the TV, instead pouring ourselves a glass of wine or indulging in a late-night snack. This creates circadian dissonance between the brain (which sees it’s dark outside) and the body (which is now full of energy to burn).
So when you eat late at night, the peripheral clocks in your liver, gut, and fat cells wake up — Hey! There’s new energy here! Time to rev things up and put this to good use! — while your brain is like: Whoa, there. It’s dark outside; time for bed.
One of the best ways to sync your central and peripheral clocks is to stop eating after 7 p.m.
Allowing the stomach several hours to empty (which is to say, while you are upright) will correct for mixed messages between your brain and body.
Or, as a more general rule of thumb, stop eating 3–4 hours before bedtime to allow your stomach to empty itself completely before your nightly fast.
Do this night limiter for 2 weeks straight before moving on.
Weeks 5–6: Time Restricted Eating (8–9 hours)
“A 16 hour fast has really kept me in great, great shape.” — Terry Crews
Ok, so at this point, you’ve been at it for a month, using a 12 hour fasting / refeeding cycle, and allowing for the stomach to fully empty before bed.
It is time to tighten up the eating window.
Going forward, we are going to have a daily feeding window of 8–9 hours, rather than 12 hours.
This will allow for a complimentary 15–16 hour fast.
This should be practised for a further 2 weeks to master and adapt to.
Restricting your eating window to 9 hours has been shown to, in addition to all the things we’ve discussed, have a significant benefit to your heart health.
Specifically better cardiovascular endurance.
When we consider that cardiovascular disease is the number one killer of women in this country, followed closely by cancer, this is not only an awesome way to shed the excess weight (and all the health conditions that come with being overweight), but it helps your quality of life, and reduces your risk of major disease.
Further evidence around stopping to eat at 7pm or 8pm is found in the literature around cancer and its reoccurence.
While cancer is incredibly complicated, there is much speculation that it is a metabolic disease, with strong epigenetic signalling from lifestyle factors that can predict it as well.
For the most of us, 65–75% of breast cancer risk is from lifestyle!
Recent studies have shown fasting to have a huge benefit in breast cancer risk reduction and its recurrence if you’ve already experienced breast cancer.
For those of us that have already dealt with cancer, specifically breast cancer, this research is showing that practicing a daily fast will reduce the recurrence of breast cancer by 40% just on its own, regardless of what your diet is.
Isn’t that incredible?!
I should mention that these results were displayed irrespective of what food was eaten. Meaning that reducing your risk for a relapse was 40% less just by fasting alone.
The bottom line here is we can grab hold of and control our lifestyle and reduce our risk and recurrence for breast cancers by 65–75%.
Sign me up.
In this study, researchers showed a profound effects on body weight in just 12 weeks of 8h time restricted feeding. These subjects limited food intake to 10:00 to 18:00h daily and demonstrated decreases body weight by ∼3% relative to the control group.
They also noted significant improvements in the reduction of systolic blood pressure relative to controls.
It is important to note this was not following any specific diet. Not a ketogenic diet (which has been shown to amplify and compliment the benefits of fasting). In this study, the participants just ate what they normally would, found they ate 300 cals less naturally.
Lets do some quick math.
300 less calories daily over the course of a year is approximately 31 pounds.
All by simply restricting your eating window.
Congrats for getting this far along in my nerd safari. You’re about 1/2 way through. If you want the simple supplementary checklist and Quickstart Guide to Fasting as a PDF download, get it right here. It’s free.
Weeks 7–11: The OMAD (aka ’24 Hour Fast’)
“When you don’t have food in your life, just for a day, it makes you realise you’re lucky to have it the next day. So the day after fasting, the music that comes out will be very joyous.” — Chris Martin
Once this 8–9 hour fasting regimen is established and comfortable, we will begin to throw in 24 hour fast, once per week.
Cool cats call this the OMAD (or, One Meal A Day) and it is just like it sounds.
It can be breakfast to breakfast.
Lunch to lunch.
Dinner to dinner.
Basically you eat one meal and then don’t eat for 24 hours.
The first time you do this- experience tells me you will feel hungry, especially around the time you usually eat.
It is important to understand that hunger comes and goes in waves.
The waves usually don’t last longer than 5–10 minutes.
If you hold out, drink water, or do something so you are not thinking about the grumbling in your stomach, you will be fine.
This study showed that a one day fast acutely increased human growth hormone, hemoglobin, red blood cell count, hematocrit, total cholesterol, HDL cholesterol, decreased triglycerides and weight compared to a day of usual eating.
Start doing one 24 hour fast in a 7 day period to start.
Then the next 3 weeks should be dedicated to a Time Restricted Eating regimen of 8–9 hours and incorporate 2 x 24 hour fasts per week.
This is serving to build up tolerance for a longer fast which we will begin working on in week 10.
After a month of practicing the 24 hours fast protocol outlined above, I will usually recommend trying one 36 h fast before the next step.
Week 12: The 72 Hour Fast
“Periodic fasting can help clear up the mind and strengthen the body and the spirit.” — Ezra Taft Benson
The following week, or week 12 in this protocol, is when the 3 day, or 72 hour fast will begin.
For more experienced fasters, this is the week when you can experiment with a 4–5 day fast.
As a general rule, I do not practice a 3 day (or longer duration fasts) more than once per quarter.
Dr. Volter Longo’s research has demonstrated lasting effects of up to 6 months following a 4–5 day fast.
When we pair this fasting regimen with a clean, plant based ketogenic diet , this is where weight loss, metabolic fitness, vitality and longevity intersect.
There are a couple things to help better your quest for longer day fasts:
Hunger Is Normal
“We can use decision-making to choose the habits we want to form, use willpower to get the habit started, then — and this is the best part — we can allow the extraordinary power of habit to take over. At that point, we’re free from the need to decide and the need to use willpower.” — Gretchen Rubin
You will feel hungry during a fast.
This is normal.
The hours around when you typically eat you should expect to hear more grumbling, and to feel the most hungry.
This feeling is a normal part of homeostasis to ensure you are being adequately fed. It is how your body keeps things in balance.
It is mediated through the hormone ghrelin which is secreted from the stomach when it is empty.
Think of ghrelin like a little gremlin that pops up and says time for nom noms!
Ghrelin job is to signal us to eat.
For my neuro nerds, ghrelin targets the arcuate nucleus in the hypothalamis, which in turn has you rumaging through your pantry to find to chow down on.
Preprandial (before the meal) rises in ghrelin have been well documented.
Look at this graph. This is how that gremlin typically operates. Look at the black line — see the spike right before normal feeding times, (8am, 12pm, and 5:30pm)?
This is the surge in serum ghrelin levels that make you start thinking about food.
You start thinking about what you want to eat, what you’re in the mood for, and you glance down and your watch and gosh — it’s just about that time!
Off to get lunch you go.
However, like anything, that can change.
Check this study out. These researchers looked at the rise and fall of ghrelin levels in subjects undergoing a 3 day fast.
What they found was participants ended up disrupting their predictable rise and fall of preprandial ghrelin levels after engaging in a 72 hour fast.
In other words, once you work your way up to a 72 h fast (which you will do slowly and methodically), you won’t necessarily be hungry at the same times you were before the fast.
This is super cool news.
It obliterates the common objections and fears I hear around hunger and fasting.
Well doc, I’ve ALWAYS been a night snacker, so how am I going to get over that? I’ve ALWAYS needed something at 2pm, etc.
The pattern can be disrupted. Your body is adaptable. Give it the tools to create better rhythms.
Goes against common thinking doesn’t it.
It would be logical to assume you would be hungrier with fasting and yet the reverse is true — your hunger levels drop with fasting.
The benefits of fasting are off the charts and far outweigh a grumbling stomach.
I’d take a temporary annoyance, at its very worst, to have a better brain, metabolism, hormonal balance, and better quality of life and vitality.
Being hungry is nothing to freak out about.
So there is a complete, 12 week course to build up to a longer term, 72 hour fast.
You can see it is gradual, with logical, small incements to allow for habituation, adaptation, and success.
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