Seven Days, No Food

17 min readMar 26, 2019

My experience with a seven day fast.

I have a long and personal history with fasting. I grew up in a family that encouraged fasting on each Friday over a two-month period each year. I not only got used to the feeling of not eating, but welcomed the weekly will-power challenge. Later in college, I would regularly fast for 18–24 hours after a long weekend of hanging out with friends doing what college kids do. I took a long break from fasting during my 20s and most of my 30s…no idea why…it just happened. But in my late 30s I got back into it, recalling how much better it made me feel after one or several days of overeating (which can happen pretty easily in Chicago, the capital of the world for amazing food).

My best friend was tea for a week. Photo by Alison Marras on one of my portfolio companies, Unsplash

Much of the work I do presently involves meetings over meals, so it’s nearly impossible to build and stick to a rigid fasting routine, however, my fasting frequency is relatively consistent, completing 1–3 days of intermittent fasting per week (anywhere from 18 to 24 hours at a time) and full fasts up to 50 hours about once per quarter.

I started reading about extended water-only fasts a couple years ago and many articles suggested visiting a facility where you could be supervised and kept on track. I think this is a great idea, and if my schedule would have been more forgiving, I would have absolutely done that. However, since that wasn’t a possible choice for me presently due to professional commitments, I set out to really dig into the extended fasting process to explore whether or not I could pull one off on my own. After doing so, I came to understand that people all over the world fast by themselves all. the. damn. time. In fact, fasting (or just going without food for prolonged periods) was a normal part of life everywhere until a few generations ago, and it is still normal for many cultures.

Armed with that knowledge, I decided to embark on my own self-administered fasting experience.

An overview of fasting

There are countless resources for fasting, but it’s been surprising to me that most people have little to no knowledge about the practice, so I thought it may be beneficial to provide an overview.

There are many variations of fasting methods, but the first major distinction is between wet and dry fasting. Dry fasting requires that one consume nothing, including water, for a an extended period of time. It accelerates cleansing benefits, but because it becomes pretty dangerous after about 24 hours, it doesn’t do much for weight loss. Wet fasting is that which allows for non-caloric liquid consumption. There is some variance of opinion on how strict one should be on a wet fast. Practices range from pure distilled water only, to that plus salt supplements, to that plus tea and other non-caloric, non-caffeinated beverages, to that plus non-caloric caffeinated beverages, and even non-caloric sweeteners. But all fasts require near-zero calories.

Other variations of fasting revolve around the frequency and duration. Intermittent Fasting (IF) involves not eating for 16–23 hours at a time and is rather fashionable these days. Extended fasting involves fasting for longer periods, usually three days and up.

Fasting is not starvation. Many people I’ve spoken with say what I’m doing sounds like starvation. Starvation is when you’re deprived of calories without your choosing to do so. Fasting is a choice to abstain from food for health reasons.

Fasting is not a diet. A diet depends on caloric reduction or caloric selection based on different qualities of calories. Fasting is the complete absence of calories. It is nearly impossible to achieve the best benefits of fasting on a calorie-reduced diet. More about those benefits next.

Motivations

The most frequent question I received when talking to people about the extended fast was “but…why?” and that’s entirely fair. I would ask the same if I didn’t have the experience I do.

First, the benefits of fasting are abundant.

Autophagy — when your weakest and most deformed cells are consumed for energy, allowing all your body’s resources to support only the strongest and best cells. Because of this, Autophagy is likely a key source of age longevity, cancer prevention, and inflammation reduction.
Increases Insulin sensitivity— over time, our cells become resistant to the effects of insulin, requiring more insulin — a cycle that often results in type 2 diabetes. Fasting helps reset the insulin resistance meter and may even reverse type 2 diabetes.
Reduces Fat
Creates ketones which not only improves overall brain function and health, but is thought to protect the brain against neurogenerative diseases like Parkinson’s and Alzheimers
Helps our immune system get stronger
Increases Human Growth Hormone (HGH) without the side effects, giving us more energy and feeling more youthful. It also increases muscle mass
Encourages mitochondria fusion and therefore, better mitochondrial efficiency, which is shown to increase lifespan
Releases toxins that have been stored with your fat
Protects against heart disease by reducing blood pressure and triglycerides, which can block arteries.

***(I’m no doctor so please talk to yours if you’re considering this, but also do your own research. Check out the links associated with each of the benefits listed above if you’d like to learn more)***

“Ok, fasting is great, but….why fast for a week?”

Primarily, I wanted to know if I could do it. I’m a sucker for a good challenge. After thinking so much about it, questions swirled for months: Could I will myself not to eat anything for a week? Would I survive? How would I feel? What would change?

Secondarily, I hoped to lose a little weight. Resources I found said to expect to ultimately lose about .5 lbs of stored fat per day (teaser: I lost a little more, but it was pretty close).

Finally, I had been dealing with migraines that seemed to be getting more frequent recently and I wanted to see if this might help.

Strategy

First, I wanted to enter the fast in a state of Lipolysis (the process by which the body mobilizes stored fat for energy use) so the switch from glycolysis (energy from glucose/sugar) wouldn’t be as challenging during the fast.

Second, It was important that I stay clear-headed throughout this process due to some important projects I was working on, so instead of a pure distilled water fast, I decided to add potassium, sodium, and (eventually) magnesium supplements.

Third, I didn’t know how the fast would affect my balance, mood, or even body odor (yes, I had heard that was a thing), so I decided to fast during a period when I didn’t need to really be anywhere crucial.

Fourth, I wanted to understand how the fast would affect my blood sugar, ketone levels, and overall weight, so I planned to keep track of each of those.

Fifth, there was a concern that I would lose muscle mass (turns out to be unfounded), so I made sure to add several weight-lifting and biking exercises into my routine and take note of deficiencies.

Finally, my wife, cautiously supportive, politely asked me not to die, so I promised her that if it started feeling dangerous, I would quit.

The Fast

Pre-fast Days 1–3

Since I intended to start my fast already in the fat-burning state of ketosis, it was important that I end the process of glycolosis by using up all my glucose.

My diet for those three pre-fast days was very high in good fat content, very low in carb content, and somewhat low in protein. I also ate about a tbsp of raw sea salt each day to keep my electrolytes up because apparently for every gram of stored glucose you burn, you shed three grams of water that is stored with it, which flushes electrolytes, giving you what some call the “keto flu.”

Drastically reducing my carb intake to around 30g per day (Day 2 required a meeting with a portfolio company and some co-investors — mandatory bourbon added 20g to the 30g) combined with two hard 45 minute cardio workouts helped me accomplish ketosis.

Using the PerfectKeto and Walgreen’s generic test strips, I tried to figure out if I was in Ketosis and frankly was surprised to see that it wasn’t as easy as it looked. Despite a high fat, low carb diet, it still took took three full days for something more than trace ketones to be produced. I’ve read that the keto strips are not a great way to measure that, and also that the protein I consumed (less than 100g each day, but ideally should have been around 70g) could have produced unexpected glucose.

My pre-fast diet consisted of variations of the following:

Pistachios and Almonds
Avocado
Chia Seeds (soaked in water for 4 hours)
Rib-eye (shout out to Swift & Sons)
Various veggies like cauliflower, onions (highest carb count), carrots, celery
Peanut butter and sunflower seed butter
Coconut Oil, Ghee, and Butter in my coffee. It sounds gross, but is actually quite tasty.
Himalayan Pink Salt

I somewhat surprisingly felt great after three days trying to get into ketosis. I don’t think it’s a sustainable long-term diet for me specifically because I still love tacos, ice cream, bourbon, hamburgers, etc., but I now better understand the appeal of the Keto diet. And a nice bonus: precisely zero headaches for three days — a rarity.

Day 1 of Water Only Fast (Wednesday)

I somewhat unfortunately started the day with another co-investor meeting over a meal. In this case it was a full keto-friendly breakfast of two eggs, some bacon, and half an avocado, along with a double espresso and a pat of butter. But after that, the fast was officially on.

Throughout the first day, I sipped on my favorite vanilla rooibos tea while working.

I didn’t expect much to change the first day, especially after a big meal. And indeed, not much really transpired. My energy level was fine and so was mental clarity throughout the day.

Around dinnertime, I tested my ketones and blood glucose levels. I decided to measure those each morning in the future.

I started to feel a little lethargic around dinner time, but I attribute that to sitting much of the day versus my normal routine of being pretty mobile. I decided to consume a half dozen pinches of salt to boost my electrolytes a little.

Day 2 (Thursday)

The night prior, I went to bed with a mild headache and needed to take an Aleve in the middle of the night, but woke up feeling really great. In the morning, I was anxious to see if my ketone levels increased and if my blood sugar numbers had subsided. It turns out both were the case. I also lost over one pound of body weight.

One of the key concerns I had going into the fast was loss of muscle/lean mass. So I decided to lift weights for 30 minutes. I actually felt really great and completed as many reps as I would have normally been able to do. The concern about muscle mass prompted me to do a little more research on that topic and found several articles that pointed out that the opposite effect actually occurs. After a few days, the body starts to increase its HGH (Human Growth Hormone), which directs the body to burn fat and put on lean mass (muscle). This was fantastic news, but I still committed myself to lifting every day of the fast to be sure that I didn’t lose any of the “good stuff” in case my body decided to start using muscle tissue instead of fat as its source of energy.

Drank about a gallon of tea and at least 1000ml of water along with about 500ml of the following concoction designed to keep my electrolytes up:

1/3 teaspoon salt
1 teaspoon LoSalt (primarily potassium with some sodium)
1/3 teaspoon epsom salt (magnesium sulfate)
1/2 teaspoon baking soda

This cocktail tasted terrible, even when chilled.

I was definitely dragging by the end of day 2. I noticed I felt pretty cold throughout the day and started to feel a little numbness in my toes and fingers. Finally, I was noticing some fogginess and was anxious to go to bed, which I did early.

Day 3 (Friday)

Slept very poorly, getting only about four hours of heavy sleep. Woke up with a headache and took an Aleve. Also woke up with a runny nose (strange) that persisted for several hours. Important day of work was ahead so I had my first cup of coffee since the beginning of the fast. It kicked in quickly and worked very well :)

After taking my vitals in the morning, I was happy to see that my ketones were finally showing up at the highest levels. I was finally burning mostly fat for energy and hoped that energy levels would increase throughout the day as a result, which is exactly what happened.

My energy and alertness levels were solid. I participated in two very important meetings and there was no noticeable difference in my performance. After my meetings, I felt energetic enough to spend an hour on our Peleton. I attribute this to three things:

coffee
the electrolyte cocktail
being in full ketosis

The only cravings I had were when my wife and kids brought home dinner from Portillo’s, one of our favorite family spots and a weekend tradition. In fairness, she had provided plenty of advance notice that I chose to ignore. But when the food arrived, I had to excuse myself because the aroma was overwhelming. Because of my newfound highly elevated sense of smell, I could still detect the french fries from our basement.

By the late evening, I frankly couldn’t tell any difference between my current physiological state and that from when I was eating normally. Other than really wanting a glass of wine while my wife and I watched a Friday night movie, it was the best I felt since beginning the fast.

Day 4 (Saturday)

Once again, sleep wasn’t great the night before and had to get up to take an Aleve with lots of water. I felt energized to the point that I was waking up for 15–20 minutes every couple hours. No doubt this is related to the adrenaline and HGH that the body produces in response to an extended fast. Either way, it was enough to send me straight to the coffee machine after taking my stats in the morning.

While helping the kids with their chores, I felt tired and irritable, so I took a quick catnap, which really helped.

I stayed pretty busy with work and housework after that, but noticed that I wasn’t 100% and was operating slowly. For example, I had to run an errand with my car and I realized after about five minutes that my reaction and judgment time was similar to that after a night of very poor sleep, so I proceeded with caution and made a note to minimize driving in the future. Finally, I still felt light-headed sometimes, especially noticeable after climbing a flight of stairs (not the best place to feel dizzy!).

I was extremely tired at night and went to bed early. I also decided to take a magnesium supplement (magnesium citrate) before bed to see if that would fend off my headaches and also help me sleep better.

Day 5 (Sunday)

The magnesium worked! On prior nights, I was achieving maybe a total of four hours of real sleep and three to four hours of noticeable awakeness. However, on Saturday night, I slept really hard for about 10 hours, with only a couple wake-ups from my kids.

I also felt good in the morning and for the first time since fasting, didn’t require an Aleve to squash a headache. I will definitely be adding the Magnesium supplement to my nightly routine for all fasting days going forward.

Sunday was similar to Saturday in that I kept myself pretty busy with housework in the morning and business stuff the rest of the day. I was able to sneak in an hour long Peloton ride in while reading Dalio’s Principles.

Sunday was the first day in which I started to think about food with some frequency. My wife made a really wonderful smelling dinner (as she often does) and then we took the kids to Cold Stone to use the gift card we gave her for her birthday. Again, because one’s sense of smell is incredibly heightened while fasting, both of those experiences made it very difficult for me to be around, so I had to excuse myself from my family. That was no fun.

My wife, concerned but curious, asked me if I felt hungry, and the answer was that while yes, I had been thinking about food primarily when I smelled it, it was surprising that I had not felt hungry throughout this process.

With all the commotion and discussion around food, I decided that I should start giving myself something to look forward to and started planning my post-fast meals. After some research, I landed on my first meal being just homemade miso soup, followed later in the day by a Kale, Spinach, Blueberry, Banana, Apple, Avocado, and Greek Yogurt smoothie.

Went to bed feeling alert and not really ready for bed. But I felt very, very cold and it was nice just to warm up under the covers.

Day 6 (Monday)

Sunday night provided the worst night’s sleep yet. The magnesium supplement fended off a headache, but did not work the sleep magic like the night before. It didn’t help that one of my boys came down with a bad cough earlier in the day and was up most of the night, but beyond that, I was just very awake and alert most of the night. My heart rate was high and my mind was racing.

However, whereas I felt groggy and slow to get going previous mornings, on this morning I strangely felt unusually awake and alert. Very little mental fogginess or lethargy…or perhaps I was just adapting to my new normal.

Upon checking my vitals, I was once again surprised to see my blood sugar rising. There is some research around why this happens and why it’s completely normal due to Gluconeogenesis (the process of the body breaking down proteins, fats, and enzymes to produce glucose,) but I anticipated it to be much lower at this stage of the fast. I was encouraged to see that my ketone levels remained at maximum levels. Final observation was that while I had been dropping nearly two pounds per day up until now, I dropped less than a pound yesterday. My suspicion was that I had flushed most of the water accompanying stored glucose.

Monday’s consumption consisted of coffee, tea, and replacing my normal electrolyte cocktail with a chicken bullion cube in hot water, which is basically just flavored salt. It was absolutely, mind-bogglingly delicious.

Day 7 (Tuesday)

I slept well the previous night, which was great because Tuesday was an extremely busy day.

I felt tremendous on Tuesday, the last day of the fast. I was ready to go another week and frankly, wasn’t yet ready to go back to eating. But I had several dinner meetings and events lined up the next three days, and was nervous how my digestive system would react if I didn’t ease into food consumption, so I decided not to pursue a longer fast.

Mardi Gras was pretty exciting for me! Before heading to bed that night, I broke the fast first with a miso soup (20 calories) and then a very small blueberry, avocado, and greek yogurt smoothie. It was surprising that instead of reacting like folks do in the movies, with a ravenous appetite, I was not really that into eating. My attitude toward food was that it had become more like fuel for sustenance than a source of satisfaction. I was curious to see how long that would last.

Post-Fast Days 1–3

Slept well the night the first night after the fast and started reintroducing food during the first post-fast day, sticking with avocado, cheese, and plenty of veggies.

It was an extremely busy three days day and I did not take my stats, which I regret, but I will say that I started to feel pretty good. A friend I saw said I looked 10 years younger, but he’s extra nice and I found that pretty hard to believe. I was feeling very thin though, so that was nice.

While I ate very well those three days, I have to say that I was very much consciously and unconsciously avoiding carbs. It wouldn’t be until several days later when I finally succumbed to a carb-heavy meal.

No refeeding issues other than some (but not a lot of) expected indigestion. I took probiotics before each of my meals to make sure I started to rebuild the bacteria required to process the food I was about to eat.

And then, after those three days, I was off to Spring Break with the family, where I knew keeping this up was going to be a challenge.

But for the moment, I enjoyed knowing that I had completed the fast and that I would absolutely, 100% do it again and again and again.

Results

Next time, I will take better pre- and post-fast measurements. Life got in the way this time.

Reflections

Most of us are really in the dark about fasting in general, which generates all sorts of fear-based responses. Most people thought I was crazy (or crazier, I should say) when I told them I was not going to eat for a week. Not everyone of course (thank you Mom, Lauren, Chris, Sal, and Michael), but most. Even several of the doctors I know were highly skeptical that this would provide any benefit whatsoever, which jaded my view of the US healthcare system a bit. My own doctor supported my plan I suppose because I had given him confidence that I had done the research.
I will absolutely do this again, but might try it in a facility. I believe in the benefits and felt amazing coming out of the fast. But fasting for a week is hard enough without the unending temptation of food all around you.
Every day got a little bit easier to the point where after seven days, I was absolutely ready to go longer and would have, had it not been for three days of business dinners that were scheduled long ago. It was hard for me to believe that people have gone as much at 382 days, but now I get it.
It was disappointing to see a lot of the lost weight come back on relatively quickly, but knowing that this was going to happen as part of the glucose storage process helped lessen the blow. In the end, I know that I’ve lost about five pounds of actual fat and I’m happy with that. I will get more accurate body fat testing done next time. I’d like to know exactly how much fat is burned and when.
I’m very glad I went into a mini-fast designed for ketosis three days prior. I think it both accelerated weight loss and also minimized the shocking effects of switching over from glycolysis (sugar burning) to ketosis (fat burning).
I think I would like to do this in the summer next time. I was cold all the time, and I’d like to know if that was because it was just cold in general or if that’s a side effect I should come to expect each time.
Finally, I haven’t had a migraine that wasn’t caused by too much imbibing since the first three days of the fast. That made all of this worth it on its own.

This experience has been really powerful for me and I’m anxious to do it again. However, I think I would like to be somewhere else when I do.

I have often thought about buying and adapting larger house or tiny hotel in order to provide a place where folks like me could fast in peace without the distraction of food and in the company of others who can share their experiences. What do you think?

Perhaps a project for another day.