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Raptitude Experiment Log No. 32 — Fasting

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In this experiment I challenge the convention that the human body is best served by three meals a day. For six weeks I will eat between zero and two meals each day, including a few two-day fasts and one three-day fast.

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This experiment started Monday April 11 and will end May 22.

The schedule is below. The number is the number of meals that day.

  • 0 = no eating
  • 1 = one meal, which is dinner (eating window of about two hours)
  • 2 = two meals, which are lunch and dinner (eating window of six or seven hours)
  • 1 or 2 = will choose based on how I feel
Week 1 – Apr 111 or 2202121
Week 2 – Apr 181 or 2202121
Week 3 – Apr 251 or 2201121
Week 4 – May 21 or 2201121
Week 5 – May 91 or 2200121
Week 6 – May 161 or 2202121

One note that may make this look less drastic: I am capable of eating an enormous amount of food in one sitting. It astonishes people. I will not have a problem getting enough calories.

I will retain a bit of flexibility in the schedule. If I feel like I need to eat, I will eat. If it’s better to switch a day around for social reasons, I will do that.

I’ll post updates whenever I have something worth saying, which won’t be every day but probably a few times a week. Follow me on Twitter to be linked to every update.

Days 1-2

Day 1 was a normal day for me — no breakfast, all eating taking place between 12 and 7pm — so there’s not much to say.

Day 2 was extraordinary. I’m pretty sure it was the first time in my forty-one years I have not consumed a calorie between waking and bedtime. There were a few occasions when I noticed hunger — such as when I went grocery shopping, and when I opened the fridge afterward to put my groceries away — but these moments were very fleeting. They also weren’t painful or difficult. More than anything I felt excited to eat tomorrow, knowing I’d have the time to make something really nice, with garnish and maybe a pickle on the side.

That was one benefit I didn’t think about beforehand — eating less often means I can eat and prepare my meals more deliberately. I don’t need to rush the preparation process because I’ve already saved several hours. Not only that, but waiting that long to eat made me feel more grateful for foods that I often view as utilitarian. Even raw red pepper seemed appetizing. (And when I finally ate it the next day, it delivered on its promise.) That day of fasting seemed to recalibrate my relationship with food so that it became something exciting again, rather than obligatory, or inevitable.

I already said in my blog posts that it was surreal to be able to use the whole day. I don’t know if I can express how big a difference this made. The time was there to finish tasks that would normally run into a meal time and have to be continued later, which inevitably pushes out the task I was hoping to begin right after lunch. It was far easier to fit the “big rocks” and the countless pebbles into the day, because it was a great big jar, rather than several small ones. I had no trouble accomplishing all of the tiny maintenance tasks I’ve struggled with my whole life. If something needed doing I could just do it right then, instead of batching it for later so that I don’t squeeze the big rocks out of their morning, afternoon, or evening slots.

The day just stretched on and on, and for the first time probably ever, I did not feel like I ran out of runway. I got a lot done, but I also fit in social activity, physical activity, reading, meditation, creative work — all of the supposedly essential supports to a happy and productive life, without having them compete with my work obligations, as they seemingly have every single day of my adult life.

I’ll give you an example. I normally go to the gym at 11:20 and arrive at 11:30. That time feels non-negotiable. If I go any earlier, I barely have time to get any work done in the morning. If I go later, by the time I work out, get home, and finish lunch and get back to work, it’s already midafternoon and only a couple of hours before the dinner process has to start. Combine this with my ADHD-related difficulties in getting tasks started and finished, and I can lose half or whole days because I didn’t perfectly navigate the delicate structure of my workday. Quite often, my morning work could benefit immensely from an extra half hour, but I can’t give it that without endangering the afternoon’s prospects. Without the imposition of mealtimes and their necessary spacing, I can start and stop tasks at more natural places, and not waste so much time.

A few curious things to note:

Energy level stayed high throughout the day. I felt like working and doing. My body felt a bit buzzy, like I had just the right amount of coffee without the unpleasant effects.

I felt more mindful and empathetic. Could just be mood.

My mind was clearer and quicker. I could think through ideas more clearly, read without losing my place so much, and — this sounds odd — music sounded better. Part of that could be mood, but I’m frequently in a good mood and this doesn’t happen often. It was remarkably similar to the effect ADHD medication had on me when it still worked — it felt like I was better able to stay on the same attentional wavelength, the same mental speed, as the music.

Day 3

I finally ate an omelet with peppers and onions as an early lunch. It was delicious. I ate it slowly, and I felt like I could have done with something smaller and lighter. I didn’t expect this, but my sense of taste was heightened quite dramatically. It was almost too flavorful. (This has remained — even on Day 4 everything seems to taste more strongly.)

Afterward, two things happened. My digestive system kicked into gear immediately — indicating strongly that I needed to “move things through,” so I did that. Apparently this is a well-known occurrence after a fast of a day or more. The other thing was a familiar drop in energy. The energetic glow of the past 36 hours dissipated, although the sense of empathy and mindfulness remained (again that might be unrelated). This energy drop wasn’t too bad, but it did return me to how I’ve always felt most of the time, and I suppose that’s just what the body feels like when it’s digesting. I never thought of digestion as a particularly demanding process, but by all accounts it is, and now I have a subjective point of contrast to appreciate just how dramatic. What I had always assumed to be my “normal” state has actually been the compromised state digestion produces in the body and mind. Digestion is a great thing, and I appreciate it more now, but it is costly and should be taken seriously. I don’t want to spend most of my life digesting.

It’s early in the experiment but I can see myself doing best with a one-meal-a-day regimen, which would occur at six or seven pm, after I’ve done everything demanding, and can then do my eating and digestion without affecting everything I want to use my mind and body for during the day.

Day 4

Already, four days in, I’ve had a profound insight about my life. It’s become clear how large a role regular mealtimes have had on my lifelong productivity difficulties.

I’ll explain what I mean by that. The basic effect of ADHD is that it makes it difficult to begin and sustain efforts to complete complex tasks. That makes all but the simplest tasks feel like monsters — they’re not just things you don’t particularly want to do, they threaten your sense of well-being and autonomy. There’s a danger you won’t get anywhere, and just waste a few more hours learning that you’re even less competent than you thought. There’s a danger you will make the situation worse. There’s a danger you’ll regret trying — you should have done something else, and hoped that circumstances will change so as to make the complex task easier while you’re not working on it.

So there’s a strong tendency to delay the beginning of many tasks, and a strong tendency to quit while you’re still contending with the hard part. Still, you know that you do have to begin, and once you’ve begun it makes sense to continue until you’re past the hard part, or you face the same trouble tomorrow, only with even more time pressure. As hard as these tasks are for the ADHD mind, you have a certain adult awareness that they are ultimately easier when you start them now rather than later, and push through the hard part rather than quit and have to confront them later.

Conventional mealtimes have always served as a kind of “safe haven” from this responsibility to begin or continue such painful tasks. Because the world says it’s lunchtime, nobody can begrudge you quitting this awful task (for now), because the body needs food! If it’s close enough to noon, it’s completely justifiable to not start this task, or not continue with it.

For me this has led to a tendency to take lunch early, and prolong it as much as possible. I also try to add other routine tasks — exercise, getting outdoors — onto the lunchtime break, to avoid adding yet another productivity-destroying partition to the day.

The more of these “safe havens” there are to partition the day, the less I get done. Lunch has ended up being almost three hours — including going to the gym and doing lunch dishes, and sometimes a short walk — and that assumes I get right back to work when I intend to, which I usually fail to do.

Without these mid-day partitions, I can keep at a task until I’ve really got something done, then go to the gym. I can break the work in more sensible places, and there’s no “safe haven island” to cling to or look forward to. Instead, there’s nothing to do but make use of the day, and there’s enough temporal space to get myself into a task and get somewhere with it before I do something else.

Combine the savings from this non-partitioning effect with the time reclaimed from cooking, eating, and cleaning up three times a day, and the actual productive time is two or three times greater. But even better, I feel like there’s space to direct the day in a way that makes sense for me.

I can see a new eating regimen drastically improving how much I get done. So far my experience has borne this out. On Day Two, and Day Four, with its single meal at 6pm, were devoid of the obligatory expanses of non-work, and the day felt enormous. I felt like I really had time to sit and work out an article idea, to debug problems, to put things back where they belong before going on to the next part of the day.

It’s early on in the experiment and I don’t know how this will settle out in terms of my lifestyle. But I already know I’ve found a way to greatly increase the amount of usable time in a day. I’ve also recognized how mealtimes have become these black holes of productivity for me.

Day 5

One issue I’ve become aware of is the impulse to indulge too much after a full or half-day fast. If I haven’t eaten all day, it can feel as though I’ve “earned” a particularly rich or unhealthy meal. Last night I ordered out, and while it was good, it was unnecessary and probably less satisfying than taking the time to prepare a nice but modest meal for myself.

When I broke my 36-hour fast, on Wednesday, I just made a nice two-egg omelet for myself, garnished with peppers and parsley, and it was completely satisfying. I’ll try to remember this impulse to overdo it, and reward myself instead with a carefully prepared meal rich in nutrients.

Day 6

Saturday, which is a one-meal-a-day day. I ran into a bit of social issue today. I had planned to have a busy day including some errands and a trip to the gym, and to begin dinner around 5pm. At about 4pm a friend invited me for dinner — at 7:00. I hadn’t planned on fasting an additional two hours — because I live by myself and work from home I have pretty much absolute control over when I do eat, and had depended on that. My decision was to have something small at 4pm rather than continue fasting. (I also know that my friend would be serving a lighter supper than I would have made for myself, given that I would be getting all my calories from this meal.

Dinner was even smaller than I thought, and by the time I got home I realized I would be subsisting on only about 800 calories today. So I ate a third small meal fairly late (9pm) to try to meet my intended intake. This is later than I like to eat and then I didn’t sleep particularly well.

I’m not sure what the right choice here was. The point is that social obligations easily give shape to our eating choices, and thankfully I don’t have many such food-influencing obligations. But it is something I will have to contend with and have some heuristics for in the future.

Day 7 – 8

Both Sunday and Monday I had two meals, which is my default anyway. One question that has come up for me is whether to observe a strict “eating window” on the days with two meals. I never have my first meal before noon, but sometimes I will have a drink or a snack after my usual 7pm stopping time, which is often convenient socially.

Given that on Mondays I’m following this last eating instance with a long fast, it doesn’t seem as crucial to begin fasting right at 7pm rather than, say 9pm — a 40-hour fast becomes a 38-hour one. However, if the next day is a 2-meal day, I’ll probably avoid it.

Day 9 – 10

So I’m learning some things by making mistakes. Day 9 (Tuesday) was supposed to be my complete fast day, but I had our usual D&D game in the evening, so I made the snap decision to move the fast day to Wednesday so that I could participate in some social eating with my friends. But then I have a roast in the fridge that needs to be cooked today so I put it in the pressure cooker, and decided to eat it for dinner instead of fasting while my house smells like Christmas dinner and then devoting 100% of it to leftovers. So fast day will be tomorrow instead.

In hindsight Tuesday is probably still the best day for the all-day fast. The “social eating” at D&D is really just junk food and alcohol, and in fact it’s the only regular occasion when I eat junk food (and eat after 7pm). When I’m fasting I’m more tempted by real food than junk food anyway so it’s probably the perfect day to opt out. It will also give me some practice having food around without partaking at all. So I’ll fast tomorrow and again next Tuesday.

Day 11

Today is finally this week’s all-day fast day. It’s been about 20 hours since I last ate and I’ll try to describe how I feel.

There’s a kind of energetic quality to it. A buzzing in the body — kind of pleasant but also a little jittery. I feel very light, vaguely like my body is less dense. I also feel calm, like a certain usual agitation is not present. I feel less reactive, less prone to being drawn into rumination. My mind seems quieter generally, but also a little… ragged? …slow? I am also cold — this could be due to fluctuations in the temperature of my house (it’s automated and kind of unpredictable) but some people do report that.

I felt this strange combination of feelings last week as well. Mood is not as great as last week, but I think that has more to do with my poor randomly poor sleep last night than anything else. Still, the body feels good. I’m interested to see if this effect deepens with longer fasts when I do them, or if I get used to it and it feels subjectively milder.

Also, I wanted to discuss some bad science reporting. The New York Times published an article today entitled Scientists Find No Benefit from Time-Restricted Eating. The headline suggests that a recent study has shown TRE doesn’t work.

The study gave 139 obese patients one of two eating protocols:

  • Restrict calories every day for a year
  • Restrict calories, and eat only between 8am and 4pm, every day for a year

Calories were restricted to 1500-1800 for men and 1200-1500 for women, for all participants. The researchers say 119 participants completed the protocol, and both groups lost weight but there was no statistically significant difference, therefore there was no benefit from time restricted eating. The TRE group lost an average of 8.0kg compared to the control group’s 6.3kg, but this difference is apparently not significant.

I think it’s quite impressive that the 8-hour eating window resulted in a 20% increase in weight loss, given that fasting advocates say it’s only after about 16 hours of not eating that the benefits begin. I would like them to test groups with 6-hour, 4-hour, and 2-hour eating windows.

This kind of reporting is a common trend in science journalism — take a culturally-popular new intervention with a growing body of research, cite a dubious contrarian study, and headline it, “Scientists Find No Benefit in Latest Thing.”

Days 12-14

The 40-hour fast ended Friday at lunchtime, and went pretty well. After about 16 hours of fasting, the low-sugar feeling starts coming and going, and I’m getting used to it. It feels like adrenaline is heightened, which I think is true, and I feel a bit spacey at times. I’ve noticed that I do well with cardio in this state, and weights I’m not sure. I feel like I have more energy (which is the adrenaline) but sometimes I feel like I should keep it light too. I’ll see how it goes this week.

So far both nights where I didn’t eat anything all day, my sleep seemed not great. I slept deeply, judging by the depth of my dreams, and how few times I woke up, but there was a kind adrenal edge to it and my dreams were stressful. Still a small sample size but I wouldn’t be surprised if this isn’t unusual.

Saturday and Sunday I ate twice, for social reasons, and will again tomorrow because my next long fast begins Monday night. I’m going to keep it as nutritious as possible to prepare the body. This will be my first 48 hour fast (or really 46-47) as I won’t be eating lunch on Wednesday. Week 3 here we go.

Days 15-16

I’m about in the middle of the 48 hour fast and I have an observation. It’s 5pm and I’m done working — I’m not particularly hungry, even though I haven’t eaten for 22 hours. I do want to eat, but I can tell that it’s entirely psychological. I’m not craving food, but I want the break, the reward, the ritual of dinner. Without it I don’t quite know what to do with myself at this time of day. There are lots of things I can do — read, meditate, call someone, work on something fun — but those all feel like square pegs for the round hole that is the absence of dinner. Perhaps that’s just because I don’t have a ritual to replace it yet. It might be a great time of day to go for a walk.

I think dinner is a pretty good after-work ritual, and when this experiment is done I will be eating only the dinner meal most days. It fits so well. The day is for doing, then the evening begins the recharging and rest period with a meal, then some lightly active evening time, then sleep. Repeat. That works for me.

So far I’m down 7 pounds and my skin looks less puffy and bloated. I’m consuming a lot of water (and decaf coffee) and supplementing with electrolytes.

I think I’ll use the dinner hour today for showering and grooming.

Day 17

Nearing the end of my first 48-hour fast and I feel great. I experienced very little of the spacey feeling I mentioned during last week’s extended fast, and I’m not sure why. Perhaps my body is getting used to the fasted state, or maybe I’m doing a better job at electrolyte supplementation, or maybe I just got a better sleep. Sleep was probably better last night, but it still has that edgy/annoyed sort of quality I don’t love.

Another interesting thing — stomach rumbling and other physical hunger symptoms tend to be infrequent, but so far they always happen a few hours before the end of an extended fast. It’s like my stomach knows food is coming. At this point I’m pretty convinced most of what we interpret as hunger is psychological, or at least psychologically-driven physical phenomena. Overall though I am less hungry and less interested in food than on the shorter fast.

I ran 5k today not having eaten for 40 hours and it felt great. The uncanny calmness/easygoingness continues — similar to how I feel after a daylong or weekend mediation retreat — and this sort of equanimity really helps me settle into the discomfort of cardio training. This also might be a coincidence.

I had an interesting test last night. It was D&D night again, which often involves snacks, so I wanted to see how it would be not to partake while snacking was going on around me. Someone brought a homemade birthday cake which looked amazing. I declined and drank my water while the others ate, and noticed a few things. It wasn’t difficult to watch people eat cake (or drink beer and whiskey for that matter) but it did get me excited about having something delicious later. I have been appreciating food more now that I eat less often (and only when I’m hungry), and I’ve found I really like deciding consciously what I’m going to have, rather than just eat what comes along if I feel I can justify it. The guilt element is gone because I’m not constantly consuming things I know on some level I don’t need. I get more enjoyment out of each bite of food, I find it more satisfying, and I’m not inclined towards large portions. It feels as though my natural impulses toward food and eating are being recalibrated to a place more in line with what my body needs.

I also noticed how quickly the cake was gone. Everybody had a piece, and within four or five minutes it was all gone, and now none of us had cake. It’s so easy to fixate so strongly on the idea of having a piece of cake or a beer or some other awesome thing that we easily overlook how ephemeral eating really is. The costs of overdoing it are long lasting though.

Day 22

Already into the second half of the experiment. Today is Monday and tomorrow I start another 48-hour fast.

There’s not much to report, as I’m getting used to this. I ate two meals (instead of the scheduled one) on Thursday and Saturday, because in both cases I was eating dinner out and didn’t want my first meal to be the chicken wings and pizza that I had planned with others. I felt it was best to give the digestive system some plants first. It was not otherwise a particularly healthy-eating weekend and I can definitely feel it. Looking forward to the next fast tomorrow.

Day 29

Week Five has begun — the week I have a 72-hour fast scheduled. Before I get to that, I need to recap last week.

Last week was supposed to include a 48-hour fast, but I bailed because I was concerned that my electrolyte formula didn’t include magnesium, which is recommended for extended fasts. Initially I had intended to take magnesium supplements in pill form, but then remembered how unpleasant taking vitamins can be on an empty stomach, and indeed the bottle says to take it with a meal. So I delayed until I could locate magnesium in a more palatable form. But I’m having trouble finding it. I ended up pushing it back until it was next week. So basically I ate normally this week — 2 meals a day, occasionally only one.

It’s Tuesday now, and I’ve officially begun the 72-hour fast, although I haven’t yet found the magnesium supplement. If I can’t find any by tomorrow I may push the 72-hour fast till next week and instead do two shorter 36-hour fasts this week. [UPDATE: I have a source and will grab some today]

Other than that there isn’t much to report. I am learning to manage the social challenges of fasting, and also harness its advantages — it’s much easier to eat no snacks at get-togethers than to try eat some but not too much. Same with alcoholic beverages.

Going from fasted state to fed state on different days continues to clarify the contrast between the two states, especially on the mind and overall well-being. I just feel better and more able when I’m not digesting food. Meals are still more enjoyable in proximity to my fasts (and not just the one I break the fast with) and I’m inclined towards more reasonable portions and a greater variety of foods.

Day 35

I accidentally broke the 72-hour fast 24 hours in. I had an international guest (a French backer via couchsurfing.com) and I took her sightseeing. Not much was open so we went to the Forks Common, and then we had beers, and only halfway through mine did I realize I hadn’t eaten anything all day and that I’d broken my fast. When we got home I served soup, so all I ate that day was a pint of beer and a soup.

There hasn’t been a good place to reschedule the 72-hour fast. It’s the last week now, and in three days I’m taking a road trip for May long weekend. So it will have to wait till I get back. It’s remarkably difficult to fit 72 hours of not-eating in a busyish social life, but I’m determined to do it.

So I’m going to extend the experiment to the week of the 23rd, during which I will do this fast. I’ve been looking forward to it. In the mean time I will continue to eat 1-2 meals a day.

Other than that there is little to report. I have lost some weight. I feel good. My days are longer. Sleep is better.

Day 44

So we are in week 7 now, which is supposed to the week I do the three day fast. I am able to fit it around my social obligations this week, but I have a major hesitation, which is that so far I have not slept terribly well on nights when I fast. My hope is that sleep improves on the second and third night. So far most of the discomforts associated with fasting go away quickly.

So I’ve decided to begin the 72-hour fast at dinnertime tonight, which is Tuesday the 24th, and break the fast Friday evening, accepting all incidental discomforts.

After that period I will make my final report.

Update: 7 June 2023

I just realized I never made my final report, and this was over a year ago. I don’t remember how I ended the experiment, but here are my basic conclusions:

  1. I like fasting. I feel better 95% of the time when I’m fasting, with the 5% being moments of weakness when I’m working out. When I’m doing cardio, I generally feel better.
  2. The major problem for me is sleep. I do not sleep well when fasted. I have too much energy and when I do sleep I am agitated. This reaction could be conditional on something else that was going on at the time, so I will try it again one day.
  3. Fasting most of the day (and eating only one large meal later on) seems to result in optimal caloric intake for me. I am probably best to eat only dinner on most days, although at the time of writing, I am in the habit of having lunch, the main reason being that I exercise mid-day and when I get home from the gym I am very used to the reward of food.
  4. I do not think I completed the 72-hour fast, because the sleep problems really make it a pain. I may try it again on an upcoming meditation retreat, and if so I will make another update below.



Kenneth April 18, 2022 at 6:50 am

Good stuff! I’ve been dieting for 4 weeks, 1,200 – 1,500 calories per day. Starting weight 203.8, current weight 193.8 down 10 pounds. My goal is 180 pounds (I’m 6 feet tall, 72 years old). I use MFP MyFitnessPal to record food and exercise. It gives me crap if I record less than 1,200 calories, telling me it’s dangerous! It refuses to do it’s 5 week projection for me which says if every day were like today, I would weight XXX pounds.

Common wisdom and knowledge about almost everything seems suspect sometimes. Thanks for your article. I might try one day of fasting just to see how it feels. I love your insight that 3 meals a day really is a time waste, preparation, eating, cleanup and feeling tired after each meal as the digestive process ensues.

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David Cain April 18, 2022 at 10:01 am

Hi Kenneth. I’m glad to hear you’re making progress. I have done calorie counting in the past and it does work for me but it’s not something I could sustain long term, which means I could not sustain the resulting weight-loss long term.

I’d suggest reading a bit about fasting. Dr Jason Fung is a prominent advocate — he treats obese and diabetic patients with medically-supervised fasting. He says people have a much easier time restricting the time of day/week that they eat than restricting the size of each meal yet having three of them a day. If what you’re doing is working, keep at it, but if you want to try another approach, the information is out there.

I recommend Gin Stephen’s book Feast Fast Repeat, which is a very practical guide to safe time-restricted eating.

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Geraldine D Kuss April 18, 2022 at 10:07 am

Whenyou start fasting you should already have prepared your body toi burn fat as fuel. Calories have been proven to be an outdated completely useless way of calculating how the human bod uses food as fuel. Carbohydrates make INSULIN go up, eaten in large quantities & it’s the Glecemic Index that is going to affect the way you feel after you eat certain foods. It’s imperative to educate yourself on HOW to turn your body fuel flexibible. Dr. Jason Fun, Dr. Andreas Eenfeldt, Dr. Sten Ekberg, Dr. Eric Berg, & others are helping the public lose the bad habits gained through mass hypnotism caused by Big Pharma & Food Industry , selling sugaR , CORN FRUCTOSE & POISON in most foods. You shouldn’t eat ANYTHING you can’t pronounce.

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David Cain April 19, 2022 at 9:43 am

It is nice to see this new paradigm being studied and taken seriously. I have read Dr Fung’s book and am making my way through the work of others. I can pronounce some pretty big words so I don’t think I’ll go by that adage, but I get the idea :)

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Burak Şahin April 18, 2022 at 11:40 am

I have fasted in every Islamic fasting month (Ramadan) all my life, and it taught me quite a bit, some of which is similar to your experiences mentioned above.
However, my most striking epiphany occurred when I tried a 3-day fasting (only drinking water) about 3 years ago. I remember that the level of consciousness was so heightened especially just before I ate, and at the time of my first bite such that it felt like other-worldly and with a completely different reality.
I wish I had noted down all the important details and realizations that came with it like you do.

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David Cain April 19, 2022 at 9:47 am

That is an interesting phenomenon, and I’m interested to see if it’s stronger after my 2/3-day fasts. Not only did my senses feel heightened, I felt much more effortlessly mindful. Today is my second 36-hour fast, and I already feel this quality building.

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Amy Siegel April 19, 2022 at 6:20 am

I’ve been eating 2 meals a day for the last 30 years. During that time I met with severe disapproval from a host of people. Recently there have been multiple sources that have begun promoting this as “intermittent fasting” and all of a sudden it is okay.

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David Cain April 19, 2022 at 9:49 am

It’s a good time to be alive, now that fasting is becoming more accepted and studied. It didn’t even occur to me that this was possible 30 years ago, and I’m sure I would have thought someone was crazy for eating only twice or once. I suppose that is the power of cultural norms — we get most of our beliefs from the feeling that something is “okay” because others think it is.

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Calen April 22, 2022 at 3:07 am

Hey, David,

Just wanted to mention something about the study you referenced earlier – the researchers found that the difference between the two groups was not significant.

Research like that one (and most research in the social sciences) is probabilistic, which simply means that the numbers found in any one study are considered unstable – if you were to run the exact same study again (say you could rewind time), it’s assumed that small differences in how the study unfolds would lead to different numbers than the original.

When the researchers say that the results aren’t significant, they don’t mean that the results are small. They mean that the results are close enough that we cannot be sure that they are not generated by random fluctuations around the same number. It’s a subtle distinction, and one that a lot of people in the social sciences (myself included) hate, because it’s unfair to people that scientific jargon produces such weird confusion when you try to translate it to the language of normal life.

The tl:dr version is this; because the measurement is not significant, that means that we can’t even talk about things like “number A is 20% less than number B” with any meaningful degree of confidence.

I’m happy to discuss further if you’re interested, and also to weigh in on whether or not the study is bad science (note: it could be generally good science and still not be grounds for concluding that time restriction doesn’t work. I can see several flaws and poor assumptions that the researchers made, just in your surface-level description of it).

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David Cain April 22, 2022 at 10:27 am

Hi Calen. Thanks for the clarification. I actually removed the “possibly bad science” remark shortly after I posted this comment, so I don’t know when you read it. I located a copy of the full study (I was going off the abstract) which removed some of the assumptions I’d made about the compliance rate.

My objection has more to do with the reporting anyway, both in terms of the the framing the NYT reporter used, but also the comments made by the lead researcher. He has done two studies on fasting, both of which employed these marginal 8-hour eating windows, and from that he has personally concluded that TRE doesn’t work and has quit doing it himself. It seems like he’s jumping the gun on dismissing something he’s barely begun to test.

Let me know if you want a copy of the study.

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David Cain April 22, 2022 at 4:58 pm

It was really odd that they combined caloric restriction with TRE. I suppose they wanted to control for calories, but they could have used a higher daily allowance.

Satchin Panda had a field day with it on Twitter today too, criticizing that and also the long eating window.

I sent a copy of the study. Let me know if you didn’t receive it.

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woollyprimate April 23, 2022 at 3:15 pm

Regarding the increased energy and keener senses, I have read that it’s nature’s way of making sure we don’t starve. If you were sluggish and dull, you wouldn’t be motivated to go look for food. I guess the idea is if you go long enough without food, the assumption is there must not be any, so you’ll have to go find it. If your senses are keen, you can see prey more easily or find an edible plant hidden among other plants, and you’ll have the energy to walk further or chase down something.

Regarding studies: there are all sorts of shenanigans that go on in studies whether it’s food and diet related or medical and drug related. People want to prove or disprove something, so they go into it with an agenda and rig the study so they get the answers they want. I always use this analogy: I’ve decided that everyone is crazy when they say that alcohol causes drunkeness, so I’m going to study it. I get 20 people enrolled in the study and I give them a tablespoon of beer every day. After 2 weeks, no one has become intoxicated, so I’ve proven alcohol doesn’t cause drunkeness. Well, everyone knows what I did. It was the dose. They do that a lot, especially when Big Pharma wants to discredit supplements or vitamins or out-of-patent drugs.

Also, they know that no one reads the study, so often they will lie when they write up the conclusion. They’ll say that such-and-such doesn’t show some effect, but if you actually read the study, it does.

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David Cain April 26, 2022 at 5:14 pm

Agreed. As much as I love and respect science as an institution, we don’t achieve anything close to true scientific disinterest. Even if studies are conducted perfectly, we easily make bad inferences from the results, and that’s even before the reporting distorts it further. Then there’s the issue of what gets studied and what doesn’t.

Dr Jason Fung published a critique of the study yesterday: https://fung.substack.com/p/fasting-has-no-benefits?s=r

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woollyprimate April 27, 2022 at 9:25 am

I’ve been watching some of Dr. Fung’s vids on YouTube (at 1.5 speed, LOL), and after reading your mention of his book, I bought it. It’s really good! I love how he debunked the idea that people weren’t fat thousands of years ago b/c there wasn’t enough food, and when we have enough food, we get fat. When food goes up, we get more regular-sized animals, not the same number of animals who are now fat. It’s true, but I’d never thought of it until I read that! He’s great.

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David Cain April 28, 2022 at 10:00 am

Which book is that? I’ve read the Obesity Code but I assume he has others

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woollyprimate April 29, 2022 at 8:27 pm

The Obesity Code.

Beth April 29, 2022 at 11:58 am

Loved the blog post and it inspired me to experiment a bit, not in a structured way but just with a gentle curiosity. I’ve tried not having dinner a couple of evenings and discovered that I wasn’t hungry at all! Maybe I’ve been eating an entirely superfluous meal a day for decades! I have no plan to make this a structured regime but am interested in continuing to play with my assumptions about how much food I need, how many meals I need.

I’m finding it is unexpectedly challenging for my partner to feel OK about, I guess dinner has always been a time for us to get together after our day.

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David April 29, 2022 at 3:28 pm

Most people who do time-restricted eating / one-meal-a-day eat dinner for that reason. It is social for most people, or most likely to be the social meal of the day. It does all have to be negotiated with the other factors in our lives.

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Mel May 4, 2022 at 5:48 am

This morning I read your day 17 entry that you are convinced that hunger is psychological and on midday stumbled across this quote in a scientifically well founded pain management book:
“When you are hungry, it is not because your stomach is sending hunger messages, there are no ‘hunger sensors’ or ‘hunger signals’. Your stomach might make a few gurgles and chemical sensors in your blood stream might have triggered ‘low on sugar’ messages, but… your hunger is made by your brain to prompt you to eat. Ever been hungry when you smelled bread cooking? That’s your brain creating hunger, not your stomach.”
So I guess science supports your thinking. :-)
The book is called “The Explain Pain Handbook – Protectometer” by CL Moseley & DS Butler (out of context here but their books are life changing for chronic pain patients)

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David Cain May 4, 2022 at 9:49 am

Thanks for sharing that. It makes perfect sense to me, and if it’s true, it’s something we should all be aware of. For years I believed that a stomach gurgle was a foolproof sign from the body that it must take in food soon or something bad will happen.

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Imran August 2, 2022 at 7:39 am

Hey David

I discovered your blog earlier this year and I love it. I’m just writing to request as to where the progress report is for this experiment etc. I can’t find a link to it in your normal experiments tab.

Best wishes.

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Jayne October 8, 2022 at 9:39 am

Hey David,
Where can I read your final report? I’ve read Dr. Fung’s book and feel that his explanation of how insulin works, why our bodies were not meant to take in food all during the day, and how we need those fasting periods to burn fat made such total sense to me. I’ve been a nurse for almost 39 years, and he’s correct in that we’ve not yet solved the reason for obesity and the massive increase in people contracting diabetes, nor how to treat it. I did my first 24hr fast day on Tuesday and was struck by how much focus and clarity I had that day. My plan is to try it 3x/week to start, get to my goal weight, then decrease the number of days to maintain, so that I can get to a new set point. I’ve struggled with weight my entire life, and over the past few years, have been 10-15 pound above my normal BMI goal. I’m hoping this will be the end of the merry-go-round of up and down. Thanks for sharing your experiment!

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Beck June 5, 2023 at 7:30 pm

That’s very interesting! All my life I’ve noticed something similar. I tend to be sluggish and irritable when hungry, more than most people I know. When I’ve fasted in the past for religious holy days, though, that sluggishness and irritability tends to dissipate for most of the day, and I feel light and energetic until mid-evening.

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