How Fasting Helps Your Body, Mind, & Gut

"Eat something, dude!”

That’s how most people reacted when I told them that I told them I was on Day 2 of putting nothing in my body but salted water, tea, and coffee.

Despite the profound and well researched benefits of fasting, it still seems so abnormal, so wrong, to walk around a kitchen full of food with a starving belly, and not indulge in the buttery croissants sitting on the counter.

I’m an avid intermittent faster, which involves restricting when I eat from 2-8pm every day, but I recently completed my first 60 hour cleanse.

Why did I feel like I needed it?

Well first of all I felt like a fat, bloated, turd. I had been eating even when I wasn’t hungry and it wasn’t healthy stuff. In fact my body was craving the wrong stuff, which is a tell-tale sign that I was suffering from the prevalent low level inflammation that makes people unproductive and fat.

Second, and most importantly, I had serious nerve pain up and down my back that spanned from my right knee up to my neck and at one point got so bad that it made my ears ring. I knew that the primary cause of my pain was scoliosis, I’ve had back problems all of my adult life, but when it got to the point that I couldn’t sit down anymore, and daily yoga wasn’t enough, I decided it was time for a fast. What does fasting have anything to do with nerve pain? I’ll get to it.

I have now completed the fast and I’m two buttery croissants deep, feeling like I’ve been reborn with no nerve pain, no bloating, and a focused, determined mind. If that sounds like something you’d like to experience, then read on.

Here’s what I’m gonna cover in this post

  • The insanely good benefits of fasting on your body, mind, and gut.

  • Twp ways to fast if you like what you hear and want to give it a try.

  • The highs and lows of my fasting experience.

Let’s get started.

How fasting helps your...


Harvard Medical School researcher David Sinclair, Phd, may be the single most respected scientist on the subject of living a long and healthy life, and here’s what he has to say about fasting, “After twenty-five years of researching aging and having read thousands of scientific papers, if there is one piece of advice I can offer, one surefire way to stay healthy longer, one thing you can do to maximize your lifespan right now, it’s this: eat less.” Whoa. Bold statement Doc.

In his book, Lifespan, he explains how fasting starves your cells, initiating a survival gene that forces your body to hunker down, boost cellular defenses, and eliminate waste. The cells that can’t hunker down because they’re either inflamed or on the verge of death, die. This cellular death is a good thing, it’s called apoptosis, which means cellular suicide, and the cells that commit suicide make room for new stem cells to harbor new, fresh life.

This survival circuit exists in all living creatures, even single celled organisms like yeast. When you feed yeast cells a lower glucose diet, they replicate slower, stay fertile longer, and have exceptionally compact DNA, all signs of healthy aging. In one study of Rhesus monkeys that were forced to fast for their entire lifetime, half of them lived to reach the age of 40, which is like a human living to be 120.

It turns out that as omnivores our bodies were built to by hybrid vehicles. It’s good for us to switch between a state of being well fed, running on glucose, and bouts of hunger, when we’re running on ketones. It makes sense because our ancestors didn’t always have abundant sources of food. They would frequently go between periods of relative bounty and periods of hunger, but in the modern world where we just walk in the grocery store and stock our fridge, very few people opt to restrict their calorie intake. Who wants to go hungry when it’s so easy to feel full?

The downside to always feeling full is that it makes it really easy for our cells to survive and replicate, even when they’ve become diseased, causing more harm than good. Glucose, the form of sugar that our cells use, signals to our bodies “Times are good! Quick, go replicate!”, but constantly feeding them the fuel they need to replicate quickly will lead to reckless behavior.

Pre-cancerous cells that our body would normally catch and kill before replicating turn cancerous, our DNA becomes less compact, which leads to less accurate transcription, and inflamed cells that trigger a stress response throughout your body, stay alive, inflaming all the cells around them.

By periodically dropping your blood sugar by fasting, you reduce your chances of the most frightening diseases including cancer, dementia, obesity, and heart disease, all by eliminating the chronic low-grade inflammation that persists throughout our bodies known as "metabolic endotoxemia”. This low grade inflammation is a pre-disease state that affects all your cells everywhere, but one place that you’ll notice the most improvements from a fast is in your mind.


Optimal Health is defined as, “complete physical, mental, emotional, spiritual, and social well-being, with peak vitality, optimal personal performance, and high productivity”, but my simple thermometer of whether I’m in Optimal Health is my ability to focus.

The level of mental clarity that I’m able to achieve is by far the biggest reason I fast, it’s like Adderall minus the future heart attacks that tag alongside amphetamines. The improved mental clarity that I achieve in a fasted state is undeniably due to the state of ketosis we talked about earlier, which simply means your body is running on fats rather than sugars.

You can achieve this in the short term with fasting and maintain it in the long term by eating a diet of 80% fats, 20% proteins, and as close to zero carbs as you can get without eliminating vegetables. Although, as I mentioned earlier, your body likes to alternate back and forth, so perpetual ketosis should not be your goal for any prolonged period of time. 

To understand the quelling effects that ketosis has on your mind and nervous system, consider what it does to even the most extreme cases of hyper neural activity, seizures.

Rahul Janial, MD, PhD is one of the top 3 brain surgeons in the world, he’s also the author of “Neurofitness” (one of my favorite books of all time). In his book he tells a story about how he went on a doctors without borders trip to Ukraine to do a few brain surgeries on epileptic children. As he walked into the Children’s Hospital the whole place smelled like bacon, but when he got to the ICU, he found out why.

On the burner that cooked the epileptic patients meals was a big slab of pig fat, which made up 100% of these epileptic patients' diets. It’s a somewhat rudimentary form of medicine that’s no longer practiced in most of the developed world, but as long as these kids ate entirely fat, their nervous system would remain calm enough to avoid sparking another neural firestorm.

(It should be obvious that eating a diet of 100% pig fat isn’t healthy, but these kids had one of two evils to battle, clogged arteries in the future or fried brains in the present. Please don’t try this diet on yourself.)

Knowing how fasting, and the state of ketosis that follows, can reduce nerve inflammation, my most recent fast was really intended to be a treatment for my nerve pain, and oh boy did it work. Fasting is like putting an ice back on your brain. It allows your nervous system to recover from the chronic inflammation that’s caused by living a busy lifestyle.

As Dr. Rahul puts it, “intermittent hunger clears the mind, awakens the sense, and improves brain functioning. Going without food for even a day increases your brain’s natural growth factors, which support the survival and growth of neurons” and when you switch back and forth between ketones and glucose, known as Metabolic Switching, it “improves monition, grows new connections between neurons, and staves off neurodegernation”.

In other words, it makes you smarter, more creative, and prevents diseases such as Alzheimers and dementia. He also mentions how a healthy brain diet consists of more than just food (and the periodic lack of it). To maintain a healthy mind you need to feed it nature, adventure, adequate sleep, tranquility, and learning. Speaking of diet, let’s see what fasting does for your gut.


Why would I include the gut as it’s own category? Because it’s far more important to your health than you think it is.

Our guts are directly linked to our brains via their own special nerve, the vagus nerve. This super highway between your brain and gut, gives our guts a special ability to influence our emotions, pain sensitivity, social interactions, and even guides our decisions making abilities—which explains that “gut-feeling” that you get when you know something is right, but you just can’t explain why. That’s because your gut is influencing the decision based on sub-conscious patterns that your logic brain can’t pick up.

In fact, evolutionary biology suggests that our gut was our first brain. Before complex creatures evolved central nervous systems, all decisions were gut-feelings. It makes sense. The first thing a complex organism needs to figure out is how to provide energy to it’s own body before it can afford to add a high calorie demanding brain into the mix. The central nervous system only evolved after our digestive systems had the capacity to feed it and up until then our guts were our brains.

What this means is that if fasting is really good for our guts, it should also be good for our mood, decrease pain, improve our social lives, and help us make good decisions—and that’s exactly what we see (once you get past the “wall” that makes people hangry).

When you fast, it triggers your migrating motor complex, which are high amplitude contractions that sweep from the esophagus to the colon while simultaneously bursting cleansing digestive juices from the pancreas and gall bladder. It’s like a street sweeping for your digestive system that reduces abdominal discomfort and bloating. It’s also the reason why calling a fast a “cleanse” is so appropriate.

That chronic low-grade inflammation that we talked about earlier that screws with our bodies and brains actually starts in our guts. It’s due primarily to diets that are high in animal products and processed foods, which trigger an immune response from our guts. It shouldn’t really be surprising that our guts are hugely responsible for our immune systems because it’s the hole that most foreign substances enter into. But as you've noticed when you get a scratch on your skin, your immune system causes swelling and inflammation, then it send that information straight up into the brain, causing brain fog and chronic low grade inflammation.

By cleansing your body with a fast, you give your guts a chance to repair themselves, eliminating inflammation, and getting you out of that pre-disease state that will wreak havoc in your body if left untreated for a long period of time.

How do you know if you’re in the pre-disease state and are due for a cleanse? The best clue we have is our eating habits. Do you feel like your body is able to properly regulate itself, telling you that you’re hungry when you’re hungry, and full when you’re full? Or are you constantly craving something to eat, even though you know you should stop eating?

In a healthy body, the hypothalamus, which is the part of your brain that’s responsible for detecting whether you’re hungry or full will regulate your eating habits for you. It knows how many calories your body needs on any given day, based on your level of physical activity, the temperature, and other factors that influence your metabolism.

A large portion of the information your hypothalamus uses to process how hungry you should feel comes straight from the vagal nerve and the hormones produced in your gut. But, here’s the kicker, if your guts are chronically inflamed, your hypothalamus and vagal nerve will be desensitized to the signals that say “Stop eating!", causing irregular eating habits and a constant craving of snacks, “just because you’re bored”.

A single day of saying no to food is enough to cleanse your guts, reset your body, prevent disease, and make you feel happy, healthy, focused, and performing at your peak.

How To Fast

Fasting is much easier than you think. At first you need to muster the willpower to say no to food, but then once your body realizes that food isn’t coming and you get past the “wall” that marathon runners endure when they switch from burning carbs to fats, then you won’t feel hungry or crave food at all.

There are two types of fast that I’m going to keep in my healthy arsenal. The first and most important is the intermittent fast.

Intermittent Fasting

The premise to intermittent fasting is that you don’t change what you eat, you simply change when to eat and that window is from 2-8pm. It’s that simple. Skip breakfast, have a coffee or tea to help with the hunger, but nothing else, and then have a late lunch, and boom you did it. Not that hard, right? I love it because it has time savings in the morning and makes me feel alert for the most important work hours of my day.

You may want to experiment with Bulletproof Coffee in the morning, which is a brainchild of Dave Asprey, author of “HeadStrong" and founder of Bulletproof Nutrition. He adds a tablespoon of grass fed butter and a teaspoon of coconut oil (or Brain Octane Oil, which just pure MCT oil) to his coffee, then blends it up into a frothy mix.

The Coconut Oil / Brain Octane Oil is full of MCTs (multi chain triglycerides) which are is the simplest, most readily available fat that humans can process, while the grass fed butter add a longer sustaining form of fats. This will keep you in ketosis in the morning, so it’s like you’re fasting, but with a few calories to supercharge your brain.

The Weekend Fast

I just gone done with a weekend fast where I stopped eating Thursday night at 8pm, then went all day Friday without eating and all day Saturday without eating. Finally, Sunday morning I broke the fast, a total of 60 hours, which is two and a half days of nothing but salted water, tea, and coffee.

Although I went for 60 hours, an alternative and still highly beneficial weekend fast that I would recommend for your first time would be a 40 hour fast, which is the equivalent of one full day fast plus an intermittent fast. To do this, stop eating by 8pm Friday, don’t eat Saturday, and then break the fast with a delicious Sunday brunch.

The reason why I call this the weekend fast is because it’s much easier to fast when you can plan some fun things to do rather than trying to do it during a work day that will exhaust your brainpower and leave you feeling drained of energy and needing food.

If you do plan to do a full day fast or longer, here are some tips:

  1. Prime your body for ketosis the night before by eating a healthy meal with plenty of healthy vegetable fats.

  2. First thing the next morning, go on a brisk walk. The goal here is to get your body past the wall and into ketosis as fast as possible. Going on a brisk walk, not a jog, not a run, will put you in the target fat burning zone and will help get your body switch to burning fats sooner.

  3. Whenever you feel hungry, drink water, tea, or coffee. The caffeine from tea and coffee will suppress your appetite while drinking water will make you feel full throughout the day.

  4. Add a pinch of salt to your water. You still need electrolytes to function normally even though you can’t have food. If you drink water without the necessary salt in it, you’ll dilute your body’s electrolytes which will lead to headaches and nausea.

In my experience…

I’m writing this a full two days after I broke my fast. My nerve pain is diminished, but not gone like it was during the fast. I still feel focused and my cravings for things like chocolate ice cream and gone. Most importantly, though, I’m in an AMAZING mood!

There were a few downsides though, that you need to know about. The obvious one is hunger. The first day was fine, but by the second day I got very hungry around lunch and dinner time. I could tell that my body expected food and didn’t get it. This was psychologically challenging and took a lot of willpower. To get through mealtimes without caving I had to distracting myself by meditating, watching a show, reading a book, or going on a walk.

The worst side-effect in my opinion was my interrupted sleep. After one day of not eating, I felt fine. After two full days of no food, sleep was hard to find. I don’t mess with things that mess with my sleep, so from now on I’m doing the 40 hour weekend fast that I recommended above 4-6 times a year and that will do it for me!

Play around with is, see what works for you. Everybody is different, so find what you like.

Do you have an experience to share about fasting? Let me know in the comments. I’ll try to reply to as many comments as I can!

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