My 6-Day Water Fast

Quick answers to common questions: Why I did it and how it went.

Why?

My main New Years Resolution for 2016 was to change my behaviour to enable me to live a longer healthier life. I did a lot of research, which I’ll briefly summarise: Realistically for most people my age in the US or Western Europe, the biggest risks to our longevity are cancer, heart disease, type 2 diabetes, Parkinson’s and Alzheimer’s.

So I did a lot of research on how to prevent these diseases — more than enough to fill several blog posts. I’ll put links to some useful stuff below. But the short answer is that, beyond genetic factors, if you don’t smoke, most of the benefits come from diet and exercise. I’ve always exercised regularly, but my diet was a problem.

For me, the biggest surprise about my diet was that fat was not the problem. Refined carbohydrates and sugar pose the main health risk. Although public health guidelines still recommend a food pyramid full of starchy grains, and “low fat” is synonymous with “healthy” on food packaging, the latest research pretty strongly indicts sugar and refined carbs as the major risk factors for all of those diseases listed above, especially cancer and type 2 diabetes, but also heart disease and age-related neurodegenerative disorders.

I made dietary changes over the course of the whole year: I cut out sugar and most simple carbs (pasta, bread, potatoes, rice) for six days out of every week, and I started eating a lot of veggies (esp. spinach, carrots and broccoli). And I started eating a lot more healthy fats — nuts, avocado, olive oil. I lost about 10 lbs (4.5 kg) and generally started feeling a lot better: More energy, consistent mood, fewer aches and pains. (This is of course all very subjective!)

I also started taking a few vitamin/supplements including fish oil, vitamin D and something called Nicotinamide Riboside. (I mention the last one with a heavy caveat as it’s early and un-proven in humans, but “generally regarded as safe” by the FDA.)

Health Benefits of Fasting?

As for fasting, the research seems pretty compelling. We have a lot of evidence that “caloric restriction” leads to longer-lived healthier adults in many species including bacteria, mice, dogs, rats, worms and humans. And proper randomized trials with fasting show profound health benefits and life-span increases in worms and mice. (A proper longevity study in humans would take 50 years, but…) Trials in humans that show improvement in particular biomarkers look pretty promising.

Here is a good recent summary of the popular science around fasting from the NY Times.

For my scientifically-minded friends who want to see the underlying research or go deep, here are two good general lit reviews in PNAS and Cell Metabolism.

More importantly, a properly conducted fast, for a middle-aged well-fed otherwise healthy adult, seems to carry minimal risks.

So you just stopped eating for seven days?

My protocol was a bit more complicated than that. I knew my first extended fast would not be easy, so I took several steps to try to ease the transition:

1. Get close to (or into) ketosis — During an extended fast, your body undergoes complex metabolic changes where it shifts from metabolising primarily glucose which comes from carbohydrates and your own internal storage, to metabolising primarily ketones, which are the by-product of breaking down fats. Your body can do either, but most of us (except people on the Atkins diet) spend our whole lives living off of carbs/glucose, and your body will always utilize glucose first if it’s present.

People who have tried extended fasts report that the first few days’ transition into ketosis can be pretty unpleasant, especially the first time. To try to ease the impact, I tried to get as close to ketosis as I could before fasting. I cut out almost all carbs two weeks before the fast started, like an Atkins “induction phase.” During this time, I wasn’t hungry, I ate as much as I wanted, but it was mainly nuts, chicken, green veg, Quorn and eggs. I lost 3kg (6.6 lbs) of water weight during that time. I worked and exercised as usual and felt fine, though at the end of that period my ketone levels were still quite low (<20 mg/dl), so I was still using glucose as my main source of energy, mainly from my body’s internal glycogen stores, which must be depleted before you can enter ketosis.

2. Clear my Calendar — I made sure that during the weekdays of the fast, my work schedule was pretty light (easier since it’s the run-up to Christmas). Especially for the first few days of the fast, as I’m expecting it to be easier after day 4, based on what I’ve heard from others who have tried this.

3. Stop Eating — Thursday night I unceremoniously scarfed down four eggs with cheese and a dash of salsa, and some fresh spinach, and said goodbye to my fork and knife for seven days. I declared my plan on Facebook and told my family and friends, to help keep me accountable. In the end, I cut it short (6 days, 7 nights), but still consider the endeavour a success, as I’ll explain below.

What did you consume during the fast?

I did drink a fair bit of water, whenever I was thirsty. In the morning I’d have a shot of espresso in hot water (9 calories). For the first few days, I mixed my coffee with 30ml of medium chain triglyceride (MCT) oil (200 calories), which metabolizes readily into ketones, to help signal to my body to accelerate the shift into a keto-adapted state. I also wanted to make sure, with all this water, that I was keeping my electrolyte levels up. So each day I’d have a glass of hot water with electrolyte powder (potassium, calcium, magnesium) mixed in. It tasted like hell. Finally to keep my sodium levels up, I’d have a half a bullion cube (fat-based) in a mug of hot water each day for dinner, which tasted like heaven. (15 calories)

Exercise? Not much. The first two days, I walked for an hour each day, to try to use up all my existing glycogen stores and accelerate the transition into ketosis.

What did you measure? Each morning and night I’d track my weight, ketone levels, blood glucose levels, blood pressure and heart rate.

How was it?

Day 1 — Not bad at all. I had a couple of meetings and a lot of desk work. I took it easy, but generally not bad. Trying to burn up my remaining glycogen, I walked 3 miles to my first meeting of the day. (Beautiful morning!) The biggest surprise was that, for most of the day, I didn’t miss food. I cooked dinner for my family and sat with them while they ate it, no problem. Giving my kids their chocolate desserts was a bit trickier. And by evening I was definitely missing certain foods. (Not hungry, just thinking longingly about some wonderful foods).

It’s weird, because eating is such a habit, I’d keep hitting these points in my day where I’d normally eat, and having to short-circuit that. (e.g. when I walk in the house, I normally grab a few handfuls of almonds, or running to a 1:00 meeting I’d think “I have time to pop in and grab a salad”). It’s not a hard/painful thing, just weird.

Day 2 — More tired but still not hungry. When I woke up in the morning, I was not interested in food at all. I slept like the dead for nine hours that first night. In the morning, my ketones were over 40 (close to being in ketosis). It was a Saturday, so I took it easy & played with the kids. In the afternoon I walked for an hour. I cooked dinner for the family, sat with them whilst they ate it. Again not super hungry, but the idea of some particular foods (a hamburger, a chocolate chip cookie) really felt appealing. I drank a cup of broth at dinner, and it filled me up and made me feel totally wonderful, despite having <20 calories.

My breath was yucky, and I had a bad taste in my mouth. That is normal/expected when you’re in ketosis. And I took a shower, which felt wonderful. I came out feeling so awake and energised!

In the evening I got a full body massage. That was really nice, very relaxing.

Day 3 — This was the worst day. I woke up (again after sleeping for 9.5 hours) feeling tired, light-headed when I stood up. Overall throughout the day, I was okay, functional, but very low energy. We took the kids on the train into town to visit a new museum, and I was really tired walking up the stairs, like the end of a long hike. I sat down and took a nap while they were colouring in some pictures. On the way back to the subway station, we passed “Ben’s Cookies.” That Ben is an evil evil man. But really other than a specific emotional attachment to certain foods, such as Ben’s diabolical cookies, I’m not really hungry.

That night I cooked dinner for the family and sat and drank my yucky electrolyte mix whilst they ate it. After dinner, Maike and I went out for a “date” at a local café, where I savoured a chamomile tea. After dinner I started feeling better, and by bed time, I was back to feeling 100% (as in just as good as I’d feel on a normal day of eating).

Interestingly, I hadn’t lost much weight at all on the fast so-far. I gained about 1kg each day from all the water, but I’d lose it again overnight. I am not doing this to lose weight. I must have lost all the water weight during my pre-fast carb-break. My glucose levels have dropped from my normal fasting level of 86 down to 55 mg/dl, which is quite low. My ketone levels are now over 40 mg/dl, and probably fuelling most of my activity. (If you’re in ketosis, your ketone levels should be between 10mg/dl — 56mg/dl).

Day 4 — Woke up feeling GREAT. Lots of energy. Took the train into town for meetings & sat and worked for hours at Starbucks, drinking chamomile tea as not to offend my hosts.

I was surprised how throughout the day I had a high energy level, even-keel mood, and was able to concentrate. On that evening, more than any previous day, I had some intense food cravings. Not hungry, just psychologically missing a few foods. (Meaning my stomach felt fine, I wasn’t weak, I had no desire for a carrot or an apple. It was really just a hamburger or a chocolate chip cookie I was fetishizing).

I have begun to lose some weight now, about 0.5kg (1lb) per day. Though I’ve begun having diarrhoea, which I’m assuming is related to the MCT oil I had during the first few days of the fast. I’ll make sure I continue to get lots of liquids and electrolytes.

Day 5 — A bit more tired in the morning. I had some broth this morning, and perked up. I was able to function fine throughout a somewhat abbreviated work day. I took rests periodically throughout the day. I do miss food, and felt hungry at times today, but not unbearable. I was easily distracted away from this, and had no problems concentrating on my work.

In the evening, again I thought a lot about food, strong cravings for very specific things. (Again, not generally hungry, no interest in carrots or apples). So I picked the exact time, date and location at which I would end the fast, and even went online and looked at their menu and picked out my dish. (Knowing full well I won’t be able to eat much of it!) But having that goal & endpoint set helps me focus and stick with it.

Tomorrow evening I’ll probably watch a movie or do something to help keep my mind off of the food cravings. Then Thursday is my last day.

Day 6 — Slept well (I’m taking 1g of Melatonin each night). Woke up feeling good, no interest in food. Had some water, and eventually a cup of dilute black coffee. I worked and concentrated happily after that.

I took my morning readings: Ketones & blood sugar are steady (~60mg/dl and 54 mg/dl) vs. previous days, don’t appear to fluctuate much. Of course my weight is down again, now 66.5kg (BMI a healthy 23). Feeling fine, taking it easy.

I worked the whole day at my desk, no trouble concentrating, really productive. But at the end of the day today I honestly felt a bit weak and tired. I had some electrolytes and broth for dinner, but definitely taking it easy tonight and looking forward to breaking the fast tomorrow (six days and seven nights, not a full seven days). I had fewer food fantasies tonight, but I was feeling a bit weak and tired.

Day 7 — Breaking the fast. I had trouble finding good information on how to break a fast. I just decided to start gently and ease my body back so I don’t have any digestive problems (assuming my stomach muscles are a bit out of practice, and it’s been a long time since I’ve produced some digestive enzymes.)

Since my body has spent the last week metabolising nothing but fat, I figured I’d start with fats as that would cause the least shock. I decided less food is better than more at first. And I should stick to healthy “single ingredient” foods rather than processed foods.

So I put some double cream in my coffee as my first calories. and I had a few handfuls of cashew nuts. From there, I gave it a few hours to see how I felt.

At lunch I wasn’t particularly hungry, but I was a bit more adventurous, I had some eggs, avocado, beans and salsa. Delicious! No problem.

In the afternoon and evening I suddenly had all kinds of uncontrollable food cravings. I’d had no stomach problems, so I went a bit crazy and ate a bunch of bread and cookies (in among normal foods). I felt fine, but really tired during and after that.

That night, I slept like I haven’t slept in years — 10 hours straight, without stirring.

Day 8 — First day after. Woke up feeling great after that long sleep! And back to my ascetic low-carb diet. Overall today I felt absolutely fabulous physically. Really strong and rested. And beyond how I felt physically, I’ve been in a really good mood, well disposed, positive and optimistic.

This might not be related to the fast, it is, after all, the first full day of my Christmas holiday. But an extended fast gives you a real appreciation for being able to eat, and the time you spend eating with the people you care about.

For Next Time

Will there be a next time? Absolutely! Why? All the science I’ve read indicates that fasting makes me healthier and reduces my risk of many common diseases by triggering a number of biological processes in my body. And it wasn’t a bad experience at all on balance.

What would I do the same or differently?

Cutting carbs two weeks prior to the fast — Good idea. I didn’t lose weight the first few days of the fast, because I dropped 2kg of water weight in the lead-up to the fast. And my ketones were >40mg/dl the second morning of the fast. Experienced fasters say the transition into ketosis can be the most unpleasant part of the fasting process, and it wasn’t too tough for me. Cutting carbs 12 days prior to my fast probably eased and accelerated that transition.

MCT Oil — Unclear. During the first few days, I had 30ml of MCT oil mixed into a single-shot of espresso with hot water each morning, hoping the presence of these MCTs would encourage/accelerate the transition into ketosis. I’ve heard this anecdotally, though I haven’t been able to find any conclusive research to say it’s true. I did get into ketosis quickly, but I also suffered with diarrhoea for four of my six fasted days. Not only is this unpleasant, but when fasting, it’s important that I retain water and electrolytes, and I’m afraid diarrhoea could be dangerous.

Duration — Good, may go a full 7 days (8 nights) next time, but this seemed to be long enough to have a good few days in a fully fasted state without being unhealthy or too physically unpleasant.

Timing — Change next time I started my fast during my last few days of work in 2016, thinking the light workload would be easier to manage in my fasted state, but also provide enough “entertainment” to keep my mind off of food. That worked nicely (I had lots to keep me busy during the day, and I had enough energy to get on with things). However right after that, I headed straight off to Christmas holiday, which is full of cookies, cakes, ice cream, served up by my incredibly gracious in-laws. So perhaps next year I’ll do the fast (or a second shorter fast) after Christmas. (Perhaps I’ll do one this year!)

Evenings’ Entertainment — Evenings were the most challenging time. After I’d prepared dinner for my family, served it to them, served the kids dessert, and watched everyone eat it, there wasn’t much to keep my mind busy, and that’s when I’d become distracted by food cravings. I was really obsessed with this mythical hamburger and some chocolate chip cookies. For next time, I’ll make sure my evenings are full of something to keep my mind busy. One evening I got a full-body massage, that was great! Perhaps other evenings I can watch movies online or do more work. (I tried going out with my wife one night, and she is brilliant, funny and engaging, of course. But sitting there sipping chamomile tea just wasn’t the most interesting/romantic date-night activity!)

Iron — Part of me wonders why I craved a hamburger specifically. I don’t normally eat them, and I don’t eat much red meat in-general (just a bunch of spinach each day). Next time, I’ll add a daily dose of iron to my small supplement regimen, just in-case my body is craving the stuff. (As a reminder, I was taking MCT oil for the first 3 days, and beyond that, my only supplements were electrolytes (potassium, sodium, magnesium, calcium). I had the sodium in the form of a cup of chicken broth each night with dinner.

Broth? I will have the broth again each night. It was fat-based and had very few calories (e.g. 20), and it made me feel absolutely wonderful. After the broth I’d feel more awake and energetic. Also, it’s a bit weird to sit with ones family at dinner and not at-least sip on something. I’m sure our ancestors, during their periods of extended hunger, did not have absolutely zero calories, I’m sure they would find and nibble on the odd root or berry now and again.

Measurements — I tracked my blood pressure, glucose, ketones, pulse and weight. They all did what was expected. Next time I’ll get a proper digital ketone meter, as those urine dipsticks are terribly inaccurate.

Fibre — I may take a glass of psyllum husk mixed with water each day next time, so that I can take advantage of my fasted state to cleanse my GI tract, though in this case, the MCT oil seemed to do a lot of the heavy lifting for me there.

Overall Thoughts & Observations

While I was fasting, I found I was generally more even-keeled, calmer, able to focus for a long time. Also, I tend to sneeze a lot with minor allergies, my nose didn’t run much at all whilst I was fasting.

Resources

A good recent summary of the popular science around fasting from the NY Times: http://well.blogs.nytimes.com/2016/03/07/intermittent-fasting-diets-are-gaining-acceptance/?_r=0

For my scientifically-minded friends who want to see the underlying research or go deep, here are two good general lit reviews:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4250148/

http://www.cell.com/cell-metabolism/pdf/S1550-4131(13)00503-2.pdf

For people who would prefer their information in plain English, with a bit less detail, I’d recommend any relevant interviews, articles or podcasts with:

Thomas Seyfried — (Boston College) Cancer prevention and treatment

Dominic D’Agostino — (USF) All things Ketosis

Mark Matson (National Institute on Aging, Johns Hopkins) — Neurodegenerative diseases including Alzheimer’s and

Valter Longo (USC) — Immune system renewal, cancer treatment