I haven’t eaten in three days and just went for a two-hour hike in the mountains followed by a swim in a waterfall.

No, I haven’t been kidnapped and I’m not lost in the jungle.

All of this by choice.

I’m on day three of my five-day fast, where I only drink water with a pinch of pink Himalayan sea salt, and juice from a few limes.

I’ve done five-day fasts several times, but for whatever reason this time seems to be the best (for me), meaning that I feel pretty good. The biggest difference compared to previous fasts has been my subtraction of any coffee or tea — now it’s just water, a squeeze of lemon and a pinch of pink Himalayan sea salt. 

The first day I started the fast, within 8 hours my mind quieted down and I actually became quite relaxed yet very alert. During dinner time I experienced a mild hunger pain for only about 10 minutes (no doubt due to the typical cycle of ghrelin and leptin), but the desire for food quickly went away and hasn’t come back these 3 days.

Hunger is an illusion.

I’ve been waking up at sunrise and it’s very easy to get out of bed — there’s no brain fog. I slept fine and might have woken up once. I’m drinking water every hour or so and consume about 3 liters+ of water a day, but more if I’m physically active outside. I also have been taking a hot bath every morning followed by a couple of cold showers throughout the day. Today, I might get a massage.

This is how I’m feeling right now: alert, focused, not hungry, very awake, energetic.

Common Misconceptions

One common misconception is that you’ll be hungry — in fact, the opposite is true. Hunger subsided for me after the first day. My body depleted it’s glycogen stores (sugar) and started use my fat as fuel (ketones), a state also known as ketosis. Ketones are like super-food for the brain and allows you to function just fine while you’re fasting. That also means no more brain fog or emotional ups and downs of fluctuating blood sugar. I feel pretty clear-headed and like I could write blog posts for hours. Maybe I will.

Another fear is that fasting for several days is somehow bad for you. Again, the opposite is true. Fasting helps lower blood sugar levels, decreases inflammation, lowers your risk of cancer, strengthens your immune system, and has even been used as a technique by diabetics to improve insulin sensitivity. Body builders also use fasting as a technique to build leaner muscles.

In fact, all the myths about fasting — it makes you burn muscle, it results in overeating, deprives the body of nutrients, “it’s starvation” — have been systematically disproven long ago, but somehow people still seem surprised by the practice. It probably doesn’t help that the damn Snickers bar commercial keeps lying to us (snickers bars will not make you less hungry…).

It’s important to note that there is nothing normal about eating 3 times a day, as our culture basically made this up and is now drilled into our heads. Throughout most of human history it was common to have periods of days, weeks or months where access to food was scarce. Not eating for several days was the norm, a way of life. If we had needed food every day, human’s would not have been able to survive and we wold not be here today.

This changed with the agricultural revolution, but many ancient societies like the Greeks understood that there was something physically (and spiritually) beneficial, so they took to voluntary fasting.

Hippocrates (who studied medicine) observed that people that were obese were likely to die faster and recommended a daily 24 hour fast. This was over 2,000 years ago.

Not to mention, almost all religions across time — like Christianity, Islam and Buddhism — have advocated for some kind of fasting. Today, millions of people continue to fast for both religious and physical purification.

For hundreds of years fasting remained relatively obscure in the West apart from religions fasting and small medical circles.

Then, over 100 years ago the author Upton Sinclair, who some of you might know from his seminal book The Jungle, also wrote a lesser known book about fasting called The Fasting Cure.

The book had no religious connotations, but rather documented Upton’s prolonged fasting strategy and his experience overcoming sever stomach issues. It inspired a wave of thousands of people with various illnesses (ranging from gastrointestinal, cardiac, metabolic all the way to the common cold) to try prolonged fasts (3-50 days), and the majority of people reporting very positive effects. It also sparked medical research on the topic — over a century ago.

Then after decades of relative silence, just in the past few years, bloggers, youtubers and podcasters have emerged like Tim FerrissDr. Rhonda Patricks and my friend Joseph Lofgren who have helped spark a resurgence in the benefits of fasting.

What Sinclair didn’t know, though, that modern science has helped to unveil was that it’s not just a good strategy for treating certain ailments, but can also be used as a preventative measure.

Today we know now that:

  • Fasting “reboots” your immune system, forcing your body to produce new white blood cells. In turn, this can help fight against disease, improve your respiratory function and even boost resistance against the common cold.
  • Studies on caloric restriction have also directly linked fasting to increasing telomere-length and preventing against senescent cells, essentially helping protect again DNA damage and increasing life expectancy up to 20%.
  • Fasting leads to mood enhancement. Not to mention it prevents against headaches, chronic fatigue and stimulates growth hormone which could help prevent Alzheimer’s.

Living longer, feeling sharper, getting less sick, and reducing impulsive eating all sound pretty good to me. It’s also logically pretty straightforward. If many of our illnesses today come from too much food and poor diets, then simply eliminating food for a period of time would seem to have benefits.

So why hasn’t your doctor recommended fasting to you? Probably because the price of fasting is zero — in fact, you save money. There’s nothing to prescribe and there’s little commercial incentive. Also perhaps because doctors don’t get any real training on nutrition in med school — on average it’s a total of 4 hours, which probably means you might have more up to date information than your doctor in many cases.

We live in a world where people know that exercise is good for you, but don’t exercise. They know sleep is necessary, but don’t get enough sleep. Perhaps there is little hope for fasting to gain adoption since it’s on an “extreme” end of the health/diet spectrum.

On the other hand — fasting is a lot simpler. It’s free, and you don’t need to follow some diet book that is doomed to fail. The barrier is of course a social one, so ultimately it comes down to self education and experimentation, since fasting is a practice we all have access to.

I’d also be excited to see fasting make it’s way into popular culture, or at the very least as a suggested option when visiting a doctor or nutrition specialist. Particularly in light of the obesity epidemic, where half of Americans are obese and 29 million have diabetes, it seems about time for the revival of the world’s oldest diet.

“The best of all medicines are resting and fasting.”

-Benjamin Franklin

To learn more about fasting, check out the following books and videos.


Disclaimer: I am not a doctor, and everyones health situation is, by definition, different. For example, children and pregnant women shouldn’t fast. I thus encourage everyone to take a smart and thorough approach before experimenting and speak with a health professional before undergoing a prolonged fast.

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