In November of 2022 I was listening to a podcast and one of the hosts casually mentioned he was on his third day of a water-only fast. At the time I didn’t think much of it, but it came up again a week later on the same podcast.
The host discussed some of the mental and physical benefits he was experiencing, this being the third or forth time he’d done it in the past few months. I was intrigued and did a little research for myself. What follows is what I’ve learned so far in my fasting journey…
Fitness and health is a big topic and I don’t claim to be an expert. I can only speak from personal experience. All the usual disclaimers apply - I’m not a doctor and any change to diet or exercise should be discussed with a medical professional.
I turn 48 this year and like many others I’ve found it increasingly more difficult to maintain healthy habits with each passing year. Having been an athlete in high school my first few years of college were a real shock to my overall health. My college job was delivering Chinese takeout which gave me access to virtually limitless bad food which didn’t help matters.
Additional details aren’t important as most people have similar stories and can already relate to the health, fitness, and weight pendulum. Needless to say, snacking too much, eating out too much, and not exercising enough have led to predictable results.
Somewhere in the middle of the month I decided to take a swing at a three day fast just to prove I could do it. Nothing fancy, I just stopped eating around 5PM on a Sunday and didn’t eat again until 5PM the following Wednesday.
The most surprising thing on my first attempt was that I wasn’t nearly as hungry as I thought I’d be. The real challenge was more psychological. Sure, there was some hunger - but mostly it was craving the sensation of eating something. I’m also the type of person who often eats because I’m bored.
Through this first experiment I learned some important lessons I’d carry through to a more robust plan in January.
The first big mistake: I ate a huge amount of food on Sunday right before starting the fast. This was a bit of panic on my part assuming I’d be starving over the next few days so I better get as full as possible. This turned out to be a dumb thing to do, as future fasts taught me that eating a lot of calories the day the fast starts takes away some of the benefits and doesn’t make you any less hungry by the second or third day.
The next lesson was that eating a large meal coming out of the fast is not a good idea. I happened to be meeting my brother for our weekly happy hour and ordered a big sandwich with fries. About half way through the meal my stomach started hurting. By the end I realized I had eaten way too much food and was pretty disappointed in myself. It felt like much of the benefit was ruined by eating way too much just prior and immediately after the fast. I also drank a few beers which didn’t sit well and I had a hard time sleeping that night as I felt sick to my stomach.
The “Fast Lane”
I decided I needed to make some changes to the fast for a more lasting impact. I could already feel the benefits during the first attempt and wanted to take it further. I decided to expand the fast to include a pre-fast warmup and a post-fast cooldown. It was also important to create a program that I could replicate and continue with long-term. I call it The Fast Lane, and am currently on my fourth iteration.
The program is ten days of modified behavior broken into three phases repeated once per month. I decided on the following pattern and have not deviated from it thus far:
- Day 1-3: The On-Ramp: This is an intermittent fast with strict rules. In the morning I have a multivitamin. Personally, I like Athletic Greens and have been taking it for a few years already. At noon I have a meal replacement shake - something with real calories and protein, not necessarily a diet shake. I’m currently using Ka’Chava for this purpose, adding some almond milk and a banana which comes in around 450 total calories. I eat a normal dinner, whatever that happens to be. If it’s pizza night, I have pizza. The main goal is to be done eating by 6PM so I get a full 18 hour intermittent fast. No snacks allowed, no exceptions!
- Day 4: The water-only fast starts on day 4 and marks the start of the Fast Lane. Per usual I’ll have my multi-vitamin in the morning and shake around noon. I try to time my last meal to complete by 4PM. This makes it easier to get through this first part of the fast and get to bed without eating anything else. In one iteration I stopped eating at noon which made it tougher on the first day as I went to bed feeling a little hungry.
- Day 5-6: Fast Lane continues - I still take my multivitamin each morning, but after that it’s water only. I also allow black coffee during this part of the fast after reading several fasting recommendations that seem to universally agree that black coffee is fine to drink during a fast with little to no impact.
- Day 7: I always wait a full 72 hours from the start - so if my last meal ended at 4PM on Day 4 I will eat my first meal at or after 4PM on day 7. This marks the end of the Fast Lane. It’s important for this meal to be on the lighter side. My personal favorite has been Pho, which is basically noodle soup with veggies. I try keeping this first meal under 1000 calories and Pho fits the bill nicely. Even with a larger bowl Pho is generally less than 500 calories. It’s also plenty of food - it’s surprising how little food it takes to get full after three days of fasting. On day 7 this will be my only food.
- Day 8-10: The Off-Ramp - The same as days 1-3, intermittent fast with a strict set of rules. Vitamins in the morning, shake for lunch, normal dinner. No snacks allowed, no exceptions!
I try drinking at least 120 ounces of water every day throughout the 10 day cycle. This is more than the average person needs - and mostly acts to keep my stomach full as well as flush out my system. There are plenty of web sites that can help you determine how much water you need based on your size and level of activity.
I also have a no alcohol policy during these ten days. The overall strategy is to maximize the benefits of the fast with a focused set of rules. This allows a lot of freedom during the two-thirds of the month I’m not fasting, effectively I do whatever I want.
After experimenting with a lighter workload during the first fast (mostly stretching and yoga), I now retain my normal exercise routine - aiming at a minimum of three to four workouts every week. These are still generally pretty light - 30 to 40 minutes of cardio or weights. It was surprising, but I have worked out on no-food days and haven’t had trouble with intensity or energy.
I’ve found it’s best to have some kind of project to work on, specifically during the water fast phase. During my January fast, I painted my wife’s office - a project that took two days and kept my mind on something other than not eating.
Stay away from anything that is a trigger for snacking. If you snack while watching TV, try to avoid TV as much as you can. Keep your mind on the goal and remind yourself how amazing the food will be in a short few days. Once I got through it a second time I realized it actually isn’t that long to commit to a modified lifestyle, especially given all the benefits.
Impact and Benefits
The impact has blown away my expectations. I imagined I would lose weight and feel better by cutting alcohol for a third of every month and eating less bad food, but there have been other unexpected side effects which have a genuinely addictive quality to them.
During the fast my mental clarity is definitely better. I tend to be at my most creative during the pure fast days. I think this is probably a combination of the fast itself and generally not needing any time or thought put towards food. The On Ramp is a good accelerator - by the time the real fast starts I’ve already had 3+ days of calorie restriction with an 18 hour intermittent fast per day, no alcohol, and improved sleep.
I’ve discovered the phrase “I’m hungry” or even worse “I’m starving” are at best exaggerations and at worst just lying to ourselves to justify eating whatever is put in front of us. On day seven as I start looking forward to that first meal I finally understand what real hunger feels like.
It isn’t at all what I imagined. Once I got past the more habitual nature of eating I realized that true hunger is when your body starts to tell you “I need food”. As I approach the 72 hour mark I feel physically weaker and start to have other minor physical side effects like occasional dizziness if I stand up too quickly.
For me, the old version of hunger is “I want to eat something” and the new version is more “I need to eat something”. It’s a small but important difference that is creating long-term healthy habits.
I should have been able to predict this, but what an amazing side-effect. Every bite of food coming out of the fast is like a new experience. That favorite restaurant that has become a little boring because you’ve been there 100 times? Not any more. All of my favorite meals are suddenly twice as good as they’ve ever been before.
As we get older and more financially secure (hopefully), the fact is we can effectively eat whatever we want, whenever we want. The foods we previously considered luxuries become common everyday meals to the point where they lose any special meaning. Services like Door Dash have made this even more difficult - click a few buttons and a 4,000 calorie meal shows up in 30 minutes.
By the third day of the fast even a basic salad starts to sound like the most glorious thing you can imagine. A simple piece of fruit is so delicious it’s like a desert. And those aforementioned favorite meals reach new levels of awesome. My appreciation for food and how it effects my body has increased ten fold.
Trailing Effect & New Mindset
With the monthly consistency of the fast there is a nice trailing effect. It takes less food to get full while not fasting. If you enjoy a drink now and then, alcohol has a bigger impact. For me this means I can enjoy a drink but limits how much I want to drink compared to the period before the fast.
Overall the extreme caloric restriction and lack of alcohol causes a natural reduction coming out of the fast that can last for, well, however long I want it to. I’ll often go extra days on intermittent fasting and will continue limiting snacks or alcohol because I’m feeling so good.
Additionally, I have a new mindset around the psychology and habitual side of eating. Before I started fasting I had breakfast every morning, lunch every afternoon, etc. Once I realized that skipping a meal or two has virtually no impact on my well-being, it became a lot easier to let those things go and not obsess about what’s for lunch. Once you’ve gone 3 full days without eating it’s pretty easy to go a half day when the timing makes sense.
This is probably the category people care about the most. And yes, while all the benefits above are amazing, being able to lose weight consistently and retain most of it is a great tangible benefit to the program.
The first thing to know is much of the weight loss is superficial. Switching to mostly water and less food (especially less sodium) means a lot of retained water is going to shed quickly. In an average 30-day cycle I tend to lose 8-10 pounds during the fast and gain about half of it back. One one occasion I gained all of it back. Much of this is likely water fluctuation, but I can honestly say much of the weight coming back is due to overeating in the period between fasts.
That being said, after three cycles (January, February, March) I have twelve pounds of permanent weight loss, starting January at 212 and retaining a consistent 200 even with a two-week poker trip to Las Vegas which I will detail out in another post. My current goals are to fast every month for 2023 and be 180 pounds sustained by the end of the year. This would amount to losing just over 2.5 pounds per month on average.
I only track my weight during the 10 day fast cycle. This is what it looks like for January, February, and March of 2023. I’ll talk more below about the time between fasts and the importance of keeping in check - but you can see from this graph that I actually started the March fast heavier than I started the February fast. This was entirely due to the bad eating I did in between.
You can also see the significant drop each time for the three day Fast Lane followed by immediate leveling off and even some gain once hitting the Off-Ramp. This data will be more valuable once I’ve got a full year to throw into a graph but there is no doubt the trend is downward.
The permanent weight loss is naturally due to eating less calories while continuing to exercise. This is fundamental to most diet plans but in this case it’s especially obvious.
I generally average around 3,000 calories per day when eating normally, amounting to 90,000 total per month. During the On Ramp and Off Ramp days I take in less than half that, around 1,200 per day. And, of course, zero calories on the fast days.
Overall, the ten day cycle reduces my calories by around 20,000 for that period, dropping my overall monthly caloric intake by 22% to 70,000 calories.
A pound of body fat contains 3,500 calories so this deficit tilts weight loss in my favor by about 5.7 pounds per month. Of course the weight loss isn’t purely from burning fat, but the math checks out given that I’m averaging about 4 pounds of permanent weight loss per month so far.
For me, permanently improving behavior between fasts is the next big challenge. Eating and other nutritional + fitness habits while between fasts is critical, and can be demoralizing if not kept under control. Who wants to go through the work of such extreme calorie restriction only to lose all the good progress by giving in to terrible habits?
In a followup post I’ll discuss a recent trip I took to Las Vegas - a place that is notoriously difficult to eat healthy. I was there for two full weeks immediately after the March fast and miraculously didn’t gain a pound. It frankly wasn’t all that hard to stick to a modified routine that set me up for success especially with how much I am learning how to eat (and not to eat).