Fasting is a very personal experience. Everyone will experience something different when they fast, and face different challenges. Also, everyone should consider whether they, personally, are ready for fasting, both physically and mentally. It’s not something to try just because someone else is doing it, nor is it something to be afraid of just because your family or friends may find the concept scandalous.
I have fasted multiple times. I’ve fallen into rhythms of 18 hours fasting, with a 6 hour eating window. Occasionally, I’ve intentionally fasted for one, two, or even three consecutive days. However, I’ve never had quite the same experience as I did fasting for five days (120 hours).
Let me just start by saying that I’m 100% fat fueled to begin with. While I don’t test my ketone levels, there’s little argument to be made that I’m not keto adapted. I have no problem skipping a meal if the only option is breaded tofu drenched in something sticky, or even skipping a salad if I know the dressing contains corn or soybean oil.
“Fasting” – true to its definition – is a friend of mine. But it took me two-and-a-half years of being ketogenic before I was able to achieve a solid five day fast.
The key to my success, I believe, was not in my experience as a keto veteran. It was in my mindset. Part of it was knowing my “Why.” I wasn’t fasting to drop weight; I knew full well that whatever weight I lost over this extended fast was probably going to come rushing back as soon as I started to eat again (and it did). I was doing this to reach the state of metabolic healing that, according to Dr. Jason Fung, tends to come after an extended fast of three days or more.
In the past, I have given up on longer fasts because I was already so taxed by other life factors that the additional stresses of intentional famine were probably not going to help me in my journey. But I reached a moment of clarity about another aspect of my life recently and, with the peace that accompanied that clarity, I knew I was ready for this endeavor. I also hoped that this period of intentional fasting would bring me even more peace and clarity.
Additionally, I had some patchy skin issues (uneven dryness, especially on my hands due to overzealous, borderline-OCD hand washing), and it was my hope that removing any inflammatory substances from my digestive system would help restore the biome that would result in healthier looking skin.
I will say right off that I chose to do this fast over a work week, so there would be less idle hours for me to notice any hunger. It’s important to plan for success, and I knew that would help.
I began on a Sunday night (which was neither dark nor stormy, but warm and muggy). I ended up eating a couple deviled eggs at night, so my 120-hour fast challenge began at 10:32 pm as I was clearing up the dish I used. Given the time, I suspected that my fast would go longer than 120 hours, since it was unlikely I’d want to disrupt my sleep in order to eat at bedtime on a work night. That start of my fast was naturally easy, as I went to bed with a full stomach and slept for the next 6-7 hours.
Monday morning was a relatively early start. I drank my coffee black and, since I don’t eat breakfast, I wasn’t bothered until about five hours after waking, when my body realized it didn’t have the fat from my heavy cream to draw from. I drank water and took crystals of Himalayan sea salt, and kept my activity levels about normal. I did some bodyweight exercises, stood at my desk, and went out to run errands at lunch.
That evening was when I started to be distracted by food cravings. Every program on TV seemed perpetually interrupted by photo montages of pizza (it was the cheese and meaty toppings I wanted, of course), or steaks from family restaurants, or burgers (which I’d eat bunless), or ice cream (of which I could happily make keto versions with The Keto Ice Cream Scoop cookbook I recently received). It wasn’t that I was craving non-keto food, I just wanted FOOD, and I couldn’t seem to look away and ignore it. I persevered, drank water, took salt, and made it to bed without incident. Another dash of hours spent unconscious, and suddenly I’m at about 30 hours fasted.
Tuesday was where things got fun. This was where I began to rack up a high score, which was a good thing, because on this day I accidentally locked myself out of the cabinet at my desk where I keep my Himalayan salt crystals! I got much less salt on Day 2, as a result of only using the Himalayan salt grinder available in the office kitchen (which my germaphobic mind could not stop imagining as a rather unsavory source of bacteria from the many hands that it comes in contact with daily). When I got home, later than usual that evening, I was cranky, probably even hangry, but I took a couple successive doses of Himayalan salt crystals and felt better within a couple hours.
Whenever anyone asks me about fasting, and how to do an extended fast, I always, always, always tell them to either go for three days or stick to one. Because hours 36-48 one-hundred percent, unequivocally SUCK.
Hour 42 is always where I consider folding and going back to feasting. And when my goal is a 48-hour fast, I frequently let myself talk me into quitting early. That’s why I tend to prefer longer fasts.
Five days? Five days is something to prove. And I don’t wimp out at 42 hours out of 120! The “High Score” feeling saw me through when a less impressive fast length might have felt unworthy of the effort.
Thus I pushed through Day 2 with more water, black coffee, and Himalayan salt crystals.
On Wednesday, Day 3, I decided to add to my detox regimen by taking Activated Charcoal capsules. I took approximately six doses of activated charcoal on Day 3, spaced two hours away from my black coffee (for potassium) and my Himalayan salt crystals (for sodium), and I took each dose with a full bottle of water, in addition to the water I would normally drink throughout the day.
Caveat: Do I think this is necessary to fasting? No.
I’d even caution that, unless you know how it works and why you’re doing it, you probably want to steer clear of the little black darlings. Activated charcoal can interfere with medicinal and nutritional absorption, and you really need to know yourself and the science of how they absorb toxins to approach it correctly. I did it as a supplemental effort to clear the skin issue I mentioned earlier. I used it successfully in the past to clear up a rash that even steroidal creams had not helped. However, this time I did not take as much or as often, and I did not see much effect from it. I hesitate to even mention it for fear of someone replicating my experiment, but in the interest of full disclosure I decided I would.
The third night I also took Chelated Magnesium Glycinate supplements to replace my body’s magnesium stores and prevent cramps and other system issues (though I had not experienced these yet, I was acting with the suspicion that the charcoal was going to make it a good idea).
Day 4, Thursday, was rather unremarkable. I didn’t really notice that I wasn’t eating. I even made two different custard recipes for Keto ice cream (Rascally Raspberry and Sassy Goat, if you’re curious) and had no issues with not licking the spatula. I took two doses of Activated Charcoal in the same manner as the day before, though I forgot after lunch to continue and by the time I remembered, I decided it was close enough to the end that I wouldn’t bother keeping up with it. So all in all there were eight doses of the activated charcoal.
On Friday, Day 5, I toyed around with eating something that night, because there was a lot of exciting talk of the types of food awaiting me. In the end it got late and I opted to wait for the morning as planned. Again, Day 5 was exciting only in the sense that I achieved my goal and had an entirely pleasant time doing it.
Actually, that’s not quite true.
At about 7 pm, I took some Himalayan salt in the kitchen while someone was talking to me. As a result of the conversation, I forgot to note the time, and ended up taking another dose of Himalayan salt about half an hour later. Too soon, as it turned out: I threw up (a side effect of taking too much sodium all at once). I mistook the sensation for hunger at first, until I realized my mouth was watering for a less dreamy reason. There wasn’t much to throw up, as you can imagine, and I felt better a moment after.
I was fine for the rest of the evening, drank more water, and had magnesium and more salt before I went to bed.
After 127 hours fasted, I woke the next morning at 5 am and had a cup of coffee with Ballistic Keto High Caliber Salted Caramel MCT Oil Powder, which had arrived earlier in the week. Two hours later, I had a couple deviled eggs (a new, fresh batch, not the same ones I had before the fast!).
So how’d it go? It went very well, almost too easy aside from a couple moments of boredom! I found that I had lots of extra energy. I had an easier time waking in the morning, I felt energized, and my body felt very powerful. In comparison, after breaking my fast I felt kinda disappointed and sluggish.
Across the ten points I measure on my body, I lost almost 6.5” inches. The scale is banished in my home, so I can’t say how much less the planet’s gravity was gripping at me after five days not eating, but I can imagine that measurement would have been lower.
A couple days after the fasting was over I noticed my skin was much clearer than it had been, though I can’t speak to other factors, such as hormones.
Since the fast? I tried to really “feast” rather than keep my calories in my usual one-meal-per-day low range. My health and measurements returned to pre-fasting levels within a few days, and my energy returned to the usual levels as well. I also felt the effects of stress again.
All-in-all it was a very pleasant experience, and I gained all the benefits I hoped for (though my improved skin may have been a side-effect of using the kitchen sink less to wash dishes and my hands after handling raw food). I can’t speak to my internal health beyond what effects I could feel, because I didn’t have blood work done before and after. From what I understand of autophagy, I ended my fast two days into a stage where my body would be recycling old cells to create new ones, so I’m sure there are longer lasting benefits of that.
Because I had such a great time, and felt so good doing it, I am considering starting another five day fast after a month. If it goes well so soon after the first, I may make a 120-hour fast a monthly thing (at least while I still have fat tissue to lose). If not, I will probably try alternating fasts or a quarterly extended fast.
Again, this was my experience. Anyone else’s would likely be different based on their situation and variables.
I want to be very clear that I am otherwise healthy. I am two-and-a-half years into my keto lifestyle, and have about 40 lbs of non-essential body fat (plenty of fuel to last through an extended fast). I am not on any medications for anything. I am not pregnant, nursing, nor planning to become pregnant. I am not a doctor, and I am not advocating that anyone should try this without first considering their personal health. You should always consult a trusted physician before making drastic changes to your diet (which includes omitting your diet entirely). Fasting should not be used solely for weight loss (most of fasted weight loss will return, and if you have a dysfunctional relationship with food you could end up making that relationship worse).
Fasting, perhaps even more than switching to Keto, should be researched and fully understood before being embarked upon. If you feel it is right for you, start with a length of fast that you feel comfortable with (though I still would caution that a 48-hour fast is all the difficulty with little of the benefit). But I will argue that if you know your body, and how to interpret the signals it sends you, fasting can be a very powerful tool for improving your health.
Like any one element of a Ketogenic lifestyle, fasting is not required for success. It’s an option, just like an avocado or HIIT workouts. I find success with it, while I don’t find success with avocados, and let’s not talk about HIIT.
We are all unique systems made up of all our moving parts, and everyone’s experience will be different. For me, fasting is a fascinating practice and one that I enjoy so much I will return to whenever I am in a state where it will benefit me.