Intermittent Fasting

Back in late September, I changed the way I eat and also what I eat. The changes those changes wrought have been both smaller and larger than I expected. What follows here are my brief notes on what I’ve learned the last 2.5 months or so.

First, here is what I did.

  1. I eliminated (more or less) all added sugars and artificial sweeteners. Every so often something slips by me; I still eat out and have no idea the added sugar quantity, and I have indulged a few times on dessert–normally only a bite or two of what the Special Lady Friend has ordered, but occasionally I have just straight up drunk an entire Oreo Blizzard with the caramel core.
  2. I eliminated, more or less, refined wheat flour. Again, this is not absolute. I have had spaghetti once, squid ink linguini once, chicken soup with egg noodles once, and probably few other things I’m not remembering. But it is a testament to my attempt that I can list, after 10 weeks, most of my violations.
  3. I have added a fiber supplement.
  4. I stopped snacking entirely.
  5. I began fasting intermittently. At least once, but normally about 3 times per week or more, I go at least 16 hours without any food at all. I start at the completion of dinner on one day and eat again 16 hours or longer later. So yes, I am sleeping for about half the time I am fasting. Every two weeks or so, I fast for a full 24 hours. Typically for this fast I start at the completion of dinner on Day 1 and then eat a late dinner on Day 2. So, for example, I may end dinner on Monday at 7pm which allows me to eat dinner at 7pm on Tuesday. As of right now I am 41 hours into a 48 hour fast that began Sunday evening and will be broken tonight–as I get better at fasting, this quarterly fast will be 72 hours long. Drinking counts as eating. So when the SLF and I have gone out to pub quiz (for example) and had a few pints, I count the end of the last drink (around 9:30p or so) as my last “food.” So I can eat again at 1:30p the next day.

41bYvpQLByL._SX332_BO1,204,203,200_This change in my eating habits was largely inspired and guided by the book The Obesity Code by Dr. Jason Fung. However, it deserves to be pointed out that several aspects of it have been nagging at my brain for several years. The nutritional science surrounding the consequences of added sugar is nearing what I consider a confident scientific consensus. Sugar is poison. The conclusion that it’s a “drug” that can cause “addiction,” is, for the moment at least, pretty shoddy science whose strongest argument is one of by way of analogy (i.e., “consuming sugar causes a release of dopamine, just like heroin does!”). I don’t find this argument at all convincing on its own.

Just from observation and some light critical thinking, it has become clear to me that if you live long enough, your heart will give out, your brain will rot, or you will get diabetes. More than likely, you will get two or more of these if the first one you get (and the second) don’t kill you first. It just seemed to be the case that you really can’t avoid causing your insulin to spike so long as you continue to consume food and drink. And persistent insulin spikes would, over time, inevitably lead to tolerance and resistance, i.e., diabetes. We’re humans. We’re finite. Our bodies get used up and stop repairing themselves. I don’t believe that intermittent fasting (IF) is the cure for diabetes or any of the other problems. But there is ample evidence that if we can avoid or postpone developing insulin resistance we can also delay our bodies natural aging process.

The changes to my eating habits were adopted (including the addition of the fiber supplement) specifically to address the production of insulin, to keep it as low as possible all the time and to occasionally get it to zero and, over time, to restore my body’s sensitivity to insulin.

To that end, getting rid of added sugars and refined grains is intended to keep the insulin levels low and fasting (and not snacking) to help insulin drop as low as possible in between meals. The sort of random, haphazard way I fast, dropping a 24- or 48- (or 72-)hour fast into the mix at the spur of the moment is to keep my body from adjusting to a new pattern.

I read The Obesity Code for work. I found the author’s argument persuasive enough to give it a try, but his enthusiasm for the power of fasting seemed to fall into evangelical levels. This always makes me uncomfortable. I have spent some time reading about why diet fads persist and how it is that people become evangelicals for a diet regimen. I’m trying not to do that myself. After reading the book I began accessing the scientific literature on the topic of IF, concentrating my attention, as I do for work, on systematic reviews and meta-analyses.

Here are the key takeaways:

In head to head studies with basic calorie restriction diets, IF performs about as well as measured in weight loss over time. On the one hand, this is a significant tempering of The Obesity Code’s enthusiasm as the author spend a great deal of time countering the notion that calorie restriction is a good dietary choice.

However, the author’s main criticism of calorie restriction is that, over time, the body adapts to the consistent low calorie food environment, permanently adjusting the body’s metabolic rate lower–burning fewer and fewer calories over time. Weight loss eventually plateaus, and maddeningly often reverses. Dieters who reduce their calories to say 1200 a day (as I have done frequently in the past) at first lose weight at that level and then eventually start to gain weight without eating any additional calories. Returning to their normal calorie intake (in my case, around 2200) causes weight to gain back to some other plateau (oftentimes higher than the dieter’s original steady weight). The author, an endocrinologist has a theory why this is the case.

According to Fung, the body has an established tolerance to insulin. This tolerance level in and individual corresponds to an ideal weight for that individual. The higher that tolerance level, the higher their weight. Moving their tolerance lower (by reducing the intensity, frequency, and duration of insulin exposure) sets the tolerance lower and lower, allowing for weight loss and allowing for that weight loss to be, if not permanent, steady. IF, according to the author, unlike calorie restriction does not permanently adjust the metabolism lower. So while both IF and CR both lower weight, the mechanisms are different and thus have different potential long-term results.

These potential long-term differences between IF and CR do not have any scientific evidence in the strictest sense. But there are some indicators that Fung’s hypothesis may yet turn out to be true. While the weight loss results between the two, IF does seem to have a greater impact on fasting insulin levels. Straightforwardly, if this is true, it should result in a slower development of insulin resistance. And, other studies indicate that both fasting and exercise can reverse insulin resistance that has already developed. Fung makes a strong case that insulin resistance is a major, if not the major factor causing weight gain (at least in contemporary advanced economies, like the US). So it is possible that long term head-to-head comparisons will find that the the weight lost by means of IF will be more sustainable than weight lost by means of CR. We shall see.

Having been a frequent partaker of CR-type diets, I felt that the science, at the very least, showed that IF was no more harmful and was at least as effective as what I have done in the past. For the last two years, I have held steady at 225 pounds. This has been frustrating because during that time I trained for and raced in a triathlon (as well as several smaller races and walks along the way. During that time, my wife and I had a baby. Technically speaking, she gave birth to the baby, but I definitely stopped exercising and began eating thrice weekly Blizzards. Regardless if I was training for a triathlon or an eating contest, my weight held steady at roughly 225. During that time I also intermittently tried calorie restriction. This would result in the immediate loss of a few pounds, but my sporadic eating habits and my disappointment in the results would conspire to end those attempts at capturing a sub-Clydesdale race weight (they call men who race triathlons above 200 pounds “Clydesdales”; women are “Athenas.”) Where I was holding those 225 pounds while training for a triathlon or eating pint after pint of ice cream was very different. But the poundage remained tenacious. Pretty strong evidence that (1) exercise contributes very little to overall weight loss/gain and (2) calories in/calories out isn’t a great model for metabolic function (two arguments effectively destroyed in The Obesity Code).

So here is what has happened so far and what I have learned.

  1. I am down 20 pounds since September 25. That’s just over 1.6 pounds a week. A pretty good rate, nothing spectacular. The current weight loss literature puts that squarely in the middle of the “1-2 pounds per week” range that is considered “healthy” and “sustainable.” I have been injured consistently since September (actually since June) and so I have exercised almost not at all in that time. I have done the most exercise in the last two weeks since I had the knee surgery that hopefully corrected that injury–but that exercise is (1) mostly confined to my legs (2) and is very light–it’s physical therapy, not performance enhancing.
  2. I don’t mind fasting very much. I fasted sporadically in high school, mostly for spiritual reasons. I would fast for three days at a time and then gorge myself afterward. I don’t gorge myself after fasts now (although I haven’t done a three-day fast yet. The literature warns clinicians that many dieters, especially “obese” individuals, might find fasting psychologically hard to do. That may be true. But I find that occasional fasts (and especially the near-daily 16-hour fast) to be way less imposing than a permanent reduction to 1200 calories per day.
  3. I find fasting easier to execute than CR. That is, when you do CR, you have to count your calories. You get better at that over time, but you never really stop. In contrast, with IF, you simply do not eat at certain times (or on certain days) of your own choosing to fit around your own schedule. And when you’re not fasting, you can eat (basically) whatever you want. Obviously, you should still try to eat “healthy” as defined above (e.g., low added sugars/refined grains) but you don’t have to count anything.
  4. I get full faster. Following the above, as time has gone on, smaller meals are actually more filling than they used to be. For me, this never happened on calorie restriction. On “cheat days” I would really cheat. My appetite was never reduced no matter how much weight I’d lost. On CR diets, I’ve twice nearly regained my college weight of 185, but I was always hungry like a 225 pound person (I topped out at 245 in 2000-01) and I always wanted to eat like one. On net, I am eating about as many calories as I would on calorie restriction over the course of the week. But I feel sated more often than I ever did on CR.
  5. Following the above, the hunger isn’t so bad. Again, I repeat that in the literature researchers have found that some individuals really find IF displeasurable, especially as it regards cravings and hunger. For the most part, I experience almost no hunger, and when I do experience hunger it isn’t ramped up above what I would normally feel in the immediate moments before a meal. That is, if breakfast filled me up at 7a, right around 11a, I would start getting hungry. If lunch wasn’t until 12p, then right around 11:50a, I would experience hunger at around a 6 out 10. For the most part, my hunger never really surpasses 6 out of 10, and it occurs at that level at predictable times…say right around 11:50. One would suppose that if it hits 6/10 at 11:50 on lunch days and on fast days, the hunger would continue growing as I continued not eating lunch on fast days. But it doesn’t. It holds pretty steady and then right around 12:30 or 1 (when I would normally be done with lunch) it begins to dissipate. It doesn’t show up again until whenever I would start getting hungry for dinner on a normal day.The big exception to that is if I eat poorly on one day and fast the next. If I eat pizza on Sunday (as I did this past Sunday) and fast on Monday (as I did this past Monday) the hunger pangs on Monday are pretty bad. They’re pretty bad right now too. If part of the benefit of fasting comes from the net calorie restriction, then it is far better to fast before the hedonistic event to come rather than after it. But I also think that we need to keep the level of hunger pangs in perspective. Even on days when I am not fasting, I will occasionally be inexplicably very hungry sometimes well before meal time. This could be caused by any number of factors, eating poorly the day before (especially overeating), being dehydrated, being triggered, being stressed, and on and on. It is unfair to assess the occasional intense hunger pang on fasting when the real culprit may be something else entirely. It is certainly the case that fasting causes one to be a lot more mindful of such things; but, being mindful does not make one immune to our psychological states. Right before my surgery I had to refrain from food from midnight one day until after my surgery the next. I had to skip breakfast the morning of my surgery….and I was pissed. And hungry. More hungry than I’d been for breakfast in months. I literally skip breakfast 3 days a week or more. I would say of the 12 weeks I’ve done this, there have been at least 2 weeks where I only ate breakfast one day out of seven. Skipping breakfast is easy and normal. But being told I could not eat breakfast that morning was a dire imposition. Such is the way our brains work. Fasting doesn’t cure that. But it also doesn’t cause it. It’s the way we’re wired. I suspect that those individuals in the research that found fasting hard to do, found it to be so because they felt it was something being imposed on them rather than something they could choose freely and execute whenever they wanted.
  6. Another thing I learned about fasting is that, for me, skipping dinner is harder than skipping any other meal. I described above how I have arranged it so that even on during a 24-hour fast I get dinners on Days 1 and 2. This is by design. I hate missing dinner. That said, when I want to do a 36-hour or greater fast, I begin at lunch on Day 1. If I finish my lunch at 12:00p, by the time I wake up the next morning, I’m already 18 hours into my fast. Breakfast is really easy to skip (even though I love breakfast) so by the time lunch rolls around, I’m 24 hours in. The accomplishment provides a lot of motivation to keep going through that next dinner.

There are things I’ve experience or learned that I’m skipping. I’m learning that the more I fast, the better I get at it. I tried a 72-hour fast last month that I had to cut short because of a small headache and some dizziness. This time, I’m well past my failure point from the last time, and I still feel strong enough that I could do a light workout. I’m learning about the importance of hydration in all of this. I’ve learned a few things about me and fiber (in addition to its insulin-lowering abilities). But I’ll stop here and maybe talk about those things and more after the holidays.