"And what is it now that you have to give? What is it that you've learned, that you're able to do?"

"I can think, I can wait, I can fast."

"That's everything?"

"I believe that's everything!"

"And what's the use of that? For example, the fasting-- what is it good for?"

"It is very good, sir. When a person has nothing to eat, fasting is the smartest thing he could do. When, for example, Siddhartha hadn't learned to fast, he would have to accept any kind of service before this day is up, whether it may be with you or wherever, because hunger would force him to do so. But like this, Siddhartha can wait calmly, he knows no impatience, he knows no emergency, for a long time he can allow hunger to besiege him and can laugh about it. This, sir, is what fasting is good for."

-- Siddhartha, Hermann Hesse

This month, I fasted for 51 hours. It was awesome. This post is going to be the perfect hybridization of “weird experiments Joe conducts on himself” combined with “Joe might think about his digestive tract a little too much,” so I hope anyone reading this is as excited as I was to write it.

Since the middle of November up until the fast that started the night of January 12, I participated in a dietary experiment called the “slow-carb diet.” In essence, I strike nearly all sugars and carbohydrates out of my diet (though I allow a little bit of fruit), and I replace those calories with extra fat, protein, and vegetables. The idea is to trigger a change in physiology to allow your body to more easily convert fat into energy as needed, rather than storing extra glucose in the body as body fat. I did not do weigh-ins at the beginning of this experiment, but I have experienced a reduction in fat around my midsection and thighs.

The slow-carb diet is a modified version of the ketogenic diet, which is the brainchild of researchers at the Johns Hopkins Epilepsy Center and is being tested for a variety of different conditions. One of its core tenets is that you begin the diet with fasting, which triggers the body to enter ketosis and begin using fat as an energy source more quickly.

Now, I do not suffer from epilepsy, nor do I have an insane desire for weight loss that would provoke me to not eat for a few days. I was curious about the impact fasting would have on my psyche. Would I have the mental discipline to go through with it? What would it feel like to not eat for three days? Would I sleep through most of it or be in hungry pain? There was only one way to find out.

So, from January 9 to January 12, I maintained strict discipline on my extremely low-carb high-fat diet, and at 6:00PM January 12, I ate my last meal in an airport. It was a Cobb salad.

On January 13, I woke up, pounded a bottle of water with some salt in it to make sure my electrolytes stayed up, and started walking around my neighborhood to stretch my legs out. I came back, more water, then had some tea with Brain Octane in it. Brain Octane is essentially coconut oil if you took out everything that wasn’t pure lipids in it. It’s a layer of concentrated oil that’s packed with fatty calories. Over the course of the 13th, I would drink about 1000 calories worth of this weird little fat cocktail in order to prod my body along into ketosis by giving it ample sources of fat to use as fuel.

I was expecting my stomach to be in physical pain for most of Friday, but that turned out to not be the case. I felt typical hunger pangs that intensified until about 3PM. After 3PM, the pangs subsided and were replaced with more of a vague awareness that I hadn’t eaten. I didn’t feel a substantial drop of energy, though the caffeine may have contributed to that. I was able to stay on track with work throughout most of the day.

After 24 hours (around 6PM on Friday) is when things started to get interesting. My mental focus went way up, though it admittedly got redirected into an obsessive desire to win a long game of Civilization V. And when I say long, I mean that I had to turn my computer off at 3AM and make myself go to bed, because I really didn’t have a desire to sleep. I was charged up. I had a manic desire to go see if I could do a distance run that I suppressed. My guess is that this is a primitive instinct to forego sleep in favor of going out to kill a zebra or something, and there is some evidence from online research that this weird shift in circadian rhythm is not unheard of in fasters. No medical evidence as to why, though.

I can’t remember exactly when I dragged myself out of bed the next day, but I’m pretty sure it was around 2PM. I woke up late, sleeping through my planned fasting halfway point of 36 hours. I didn’t really feel like getting out of bed but felt I should at least get the blood pumping. Little bit more tea with Brain Octane. More water - at that point I was wickedly dehydrated from being in bed for almost twelve hours. I kicked the water consumption into high gear, because I was starting to experience an occasional heart palpitation and headache that I thought might have been due to a lack of electrolytes.

Still, at this point, I was bored. I was tired of sitting in my house. I was tired of doing the same lazy activities, which surprised me because I thought I loved lazy introverted activities enough to do them for an entire weekend. This was not true. I didn’t physically feel weird, aside from a slight weakness that I’ve felt before after recovering from an illness. I hit the 48 hour mark, fist-pumped, and thought I was going to cruise through the final 24 hours with ease.

That turned out to not be the case. This is where the “you should probably do this sort of stuff with medical supervision” comes in.

From Hour 48 to Hour 51, I started thinking hard about food. I wasn’t getting hunger pangs, but I couldn’t stay focused on anything because the thoughts of food were all-consuming. That was an interesting sign. My headaches came back and I started drinking more water. I started feeling physically weaker. At Hour 51, I started getting a churning feeling in my stomach like I was about to vomit, and when I burped, there was a taste in my mouth that I didn’t like at all. I decided that was a combination of physical symptoms that I didn’t want to discover was a sign of something bad, so I canceled the experiment. I walked to go get a burrito and a torta and the local burrito shop.

Refeeding was a pretty straightforward affair. I nibbled on the food consistently for about 2.5 hours, as I was a little nervous that it might come back up if I didn’t practice some discipline. I didn’t feel greasy or gross after taking out an entire torta and half a burrito (with rice). I didn’t really feel full. Just sort of contented. I still couldn’t get to sleep before 3AM.

I set my alarm for 9AM the following morning to try to force my circadian rhythm back into some sense. I ate the other half of the burrito. I went to brunch. I had pizza for dinner. The combination of all of these things would normally put me into a coma without some serious exercise. No sense of illness, no sense of bloat. I have not resumed the high-fat, low-carb diet since the fast ended. I have, however, found myself naturally restricting my portions throughout the day and eating larger meals at night. Something I might tinker with in the coming weeks.


So, what have I learned?

  • I will absolutely do this again. It was an extremely interesting mental shift and a way to shake up my relationship with food.
  • You should definitely not try this if you’re trying to lose weight. For starters, it wasn’t really effective for that. Perhaps more concerning than that, though: you might actually cause a medical trauma to yourself. I picked up the burrito because something didn’t feel right. If you’re trying to lose weight rather than just paying attention to how you feel, you might not make the same choices.
  • If you’re trying for weight loss or body recomposition (i.e., less fat in bad places), I highly recommend trying the slow-carb diet over an eight-week period. It worked wonders for me without a lot of struggle.
  • If you’re trying the slow-carb diet, you should do your homework and you shouldn’t try to mix and match with other diet plans. I’m mostly speaking about the fat content of the diet here. You cannot, absolutely cannot, listen to the “low carb” portion of this diet and ignore the “eat lots of fat” portion. My breakfast when slow-carbing was four eggs, Greek yogurt, beans, spinach, and whole milk. Do not try to dodge the fat.
  • I probably don’t need to eat the portion sizes I do. Or rather, I should make sure to tailor my eating to the amount of exercise I’m actually doing that day rather than the exercise I think I should be doing that day.
  • If I don’t eat for an entire day, it will not make me grouchy if I go into it with the right attitude. It does, however, help to plan for that.

I tried to be as detailed as I could about my experience with fasting. If you have any questions about what it was like, or are curious about trying it yourself, I’m happy to answer what I can!