Quick Tip - Reset Your Gut Microbiome in 48 hours by Fasting

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A 48 hour fast I’ve found is a short enough time period to be accomplished by an ordinary individual with little preparation.

By why would you want to fast, not eating anything, for two days straight?

Through my own personal experience, the anecdotes of others, and new scientific research, it’s been known that fasting for an extended length of time can radically transform ones gut health and digestion, in the process fixing many of the modern ailments so common nowadays such as poor sleep, a lack of energy, skin issues, and obesity.

Through fasting, you can reset your gut microbiome, therefore improving overall bacterial diversity while also reducing in the amount of harmful bacteria you harbor.

When these conditions are in place, your gut is able to function properly, providing good consistent energy, restful sleep, clear skin, and a thin waist line all by reducing your bodies overall level of inflammation.

In a double manner, a 48 hour fast is a great way to experience these amazing positive effects for yourself.

Girl Lost Weight Loose Pants

Also, did I mention that improving your gut health through fasting can help free you from a variety of digestion woes such as brutal stomach aches, intense bloating, waves of nausea, or even running-to-the-door bathroom trips, all of which put a big drain on your day.


A healthy microbiome will give you great digestion every day, good utilization of carbs for energy, and can stably provide you energy when fed with fat.

And this can all be accomplished with an idea as simple as a 48-hour fast.

The 48 Hour Fast

The 48 Hour fast is simple. You don’t consume any calories, aka food or drinks that contain calories, for 48 continuous hours. Water of course is allowed, as are zero calories beverages such as black coffee or tea.

Nervous to try 48 hours? Even a 24 hour fast can help heal your gut and teach you the difference between hunger and cravings.

I like to start a fast after dinner, as the first 10-11 hours will be easily accomplished by sleeping. Then upon waking, breakfast is easy to skip if one drinks plenty of water and keeps moving. Lunch is the hardest, as it’s a natural drowsy point of the day, but a 15 minute nap, quick walk, or cup of coffee fixes that easily.

With dinner, you’re now well underway with burning body fat for energy, and from here you just need to keep your car on cruise control, avoiding the traffic jams of life. To finish the 48-hr fast, just simply skip breakfast and lunch again, and then resume eating with dinner. To go longer, keep avoiding food instead just listening to your bodies needs as you place it in this position of increased stress.

A 48-hr fast is like a nuke to your gut. No food means your microbiome has to scavenge and work extra hard to survive in a low resource environment. And some bacteria are better suited to survive in that environment than others.

An Unhealthy Microbiome

*Why? For possible energy reutilization by the bacteria during a time of stress in the future. The inverse is a microbiome that is confident it will be fed well consistently will trust the host, partitioning nutrients towards muscle rather than fat storage.

*Why? For possible energy reutilization by the bacteria during a time of stress in the future. The inverse is a microbiome that is confident it will be fed well consistently will trust the host, partitioning nutrients towards muscle rather than fat storage.

With an unhealthy gut, your microbiome is one that preferentially craves sweets, fried foods, and salt, and rewards you with brain fog, unstable energy levels, and fat gain*.

The bacteria that make you feel awful are not helpful in very few endevours, and to accomplish the difficult transition from an unhealthy to healthy gut, your goal is to kill off as much of your microbiome off as possible. A 48 hour fast will kill off a good majority of one’s microbiome. Unfortunately, good as well as bad. Luckily, the good bacteria that reside in ones gut are much more resilient, and the processed-food loving bad bacteria die off in much greater numbers than the whole-food, vegetable loving bacteria.


Your Own Gut Cells

And with all this talk of the microbiome, don’t forget about your own cells in your gut, those on the front line, the epithelium.

The epithelium (barrier to your intestines), regenerates with new cells completely every 5 days. Everyday, 20% of the epithelium is regenerated. Therefore, the longer the fast, the greater the percentage of your intestinal cells that will have regenerated.

A two day fast will allow 40% of your epithelium to completely regenerate in a “cleaner” environment free from an overwhelming amount of bad gut bacteria and surrounded by less food.

My Personal Experience

At the end of a 48 hour fast, I notice a few things:

First, I’ve found that when I reintroduce vegetables into my diet, I am suddenly able to digest them much easier thanks to a greater percentage of vegetable digesting bacteria in my gut.

Second, my fat burning metabolism improves noticeably. Since I eat a diet rich in healthy fats, I am already very good at seamlessly transitioning between fats and carbohydrates for energy. After a fast, those energy dips that happen throughout the day are smoothed out much faster by a metabolism that is able to quickly switch to fat burning when consistent energy is needed.

Third, my gut is very thankful for the break in digestion. When you’re digesting day in and day out with no breaks, it’s easy to overwork and stress your digestive system out, which leads to inflammation. A 48 hour fast will improve my microbiome, but will also improve things like heal intestinal tight junctions, help to reset a food intolerance(s), and more.

Enough Talk, Here’s an Action Plan

Interested in healing you gut by trying a 48 hour fast? Here’s a step by step guide to help you easily accomplish this task and to therefore experience the positive effects outlined above for yourself.


  1. Drink More Water

    • The day preceding when you start your fast (after dinner), drink more water. Less food intake meals you’ll need to drink more, so drinking more water beforehand will be prepare you to be successful.

  2. Eat Dinner Early and then Sleep 8 Hours

    • After a full dinner it’s easy to put the snacking and cravings aside, so it’s the perfect time to start a fast. Eat a early dinner at 7pm, and go to sleep at 10pm. After a full eight hours of sleep you’ll be well rested, ready to attack the day, and 11 hours (nearly 1/4) into your first fast.

  3. Listen to your Body, but Set Rules for Yourself

    • Once you’ve waken up, you now have to make it to bedtime again without eating. Listen to your body, keep drinking water, and follow the energy. If you feel sluggish and hungry sitting at work for example, get up and move around*. Keep yourself active, take a short restful nap, or drink something lightly caffeinated like green tea.

  4. Trust yourself

    • Once you’re in cruise control, look forward into your day or schedule and plan around the chaos of the everyday. Set order and structure for yourself in order to stay healthy and on track.

  5. Reintroduce Food, Slowly!

    • Once you’ve finished your fast for however long, reintroduce food back into your lifestyle. I would not recommend eating a huge meal after a fast; start simple! Bone broth, steamed veggies, or soup are all good choices. The longer your fast the longer your food reintroduction period should be.

*By lunch, about 16 hours into the fast, you’ll have exhausted all glycogen (carbohydrate) energy sources for your body and will be officially be burning body fat. Your brain will start to run on ketones after about 48 hours.



Success! Now What?

Congratulations, you’ve finished your first 48 hour fast! But, after having done it, what now?

Person in Sunset

The question of “what now?” is where most people make a mistake when it comes to permanently improving their health and wellness. Instead of paying attention to how they feel during the process, in this case fasting, many people only focus on the end result. They see success, but afterwards are no more well equipped than when they started because they didn’t learn how to use the tool they were being taught.

You might be surprised to learn your daily aches and pains have a connected to your diet!

You might be surprised to learn your daily aches and pains have a connected to your diet!

So during this fast, pay attention! Pay attention to everything. Pay attention to your food cravings in stressful situations, your hunger ebbs and flows, your mood in different environments, your energy levels throughout the day, your bodies regular aches and pains, your quality of sleep…everything!


Anytime I learn a new health, wellness, or fitness tool I add it to my toolbox. Consider fasting an important tool to master to use as your wish understand.

A good example of that is how I fast when I travel.

Traveling, especially internationally, is very stressful on the body. Long hours, bright airport lights, time spent at altitude (~6000 ft), a disrupted circadian rhythm, a general lack of sleep, and poor quality food all place the body in a compromised immune state. My strategy to eliminate the poor/junk food stressor is to completely skip eating in the first place.

24 hours is the longest travel day you’ll typically encounter. Over that time period you’ll have skipped 3 meals, which is one huge less stressor to worry about as you’re already stressed from rushing to catch your flight, inadequate rest, and being narrowly confined for hours. If I don’t eat while traveling, I find myself having much more energy, because I reducing my overall travel stress.

Wrap Up

There you have it! Give it a try, either a 24 hour fast or a longer 48 hour fast, and see what happens! I can promise that if you pay attention to yourself during the process you’ll end having learned a lot about yourself, and you’ll have an understanding of how to use fasting to optimally improve your health, however you see fit.

Please only do this if you are ready, physically and mentally, to go through a period of no food consumption. If this will be dangerous to you, please do not attempt this. All information, content, and material of this website is for informational purposes only and are not intended to serve as a substitute for the consultation, diagnosis, and/or medical treatment of a qualified physician or healthcare provider.


If you want to learn more about extended fasting, I highly recommend you watch the fantastic documentary, The Science of Fasting, found on Amazon Prime Video.

To track how long you’ve been fasting, I recommend you use an app such as ZERO (found on iTunes and the Google Play Store).

If you want to actually test your microbiome microbial diversity before and after a fast (of any length, longer is recommended though), I recommend uBiome’s at home SmartGut test.


Stefan Burns

Stefan Burns is the creator and main author of Wild Free Organic. A swimmer in high school, soon afterwards he discovered a passion for the health, wellness, and fitness fields. Stefan is a jack of all trades, expertly knowing how to use all the different wellness “tools” available to radically and permanently transform one’s health, from fasting and sauna usage to calisthenics and powerlifting.

To learn more about Stefan Burns visit his website or follow him on Instagram @stefanburnswellness.