Friday, September 4, 2009


Unfortunately, there’s a lack of good science when it comes to fiber. One is forced to rely on experience, anecdote and extrapolation, which is of course not quite as forceful as a measurement or controlled observation.

Still, I can come up with a testable hypothesis (one which I am in the process of testing, and which you can too; more on that later). So I will start there.

A common theme of questions about my diet surrounds bowel function. “Aren’t you constipated?” “Doesn’t meat take a week to digest?” “Doesn’t meat putrefy in your bowels?” The answers, respectively, are no, no and no, but since this is a blog I will put a little more effort into my response than that.

The first question is very easy to answer and indisputable: I am not constipated. I can measure this daily. In fact, for the past four days (reading from my log-log here), I have gone to the bathroom zero to two times per day. All bowel movements have been small, solid and have required no strain to pass. I feel like I have to go, I sit down, and within a couple minutes of wondering if that’s really it, I am on my way back out the door marveling at my excretive prowess.

The results speak for themselves. Constipation is a non-issue on this diet. Now, for the more curious, the question of why I’m not stuck in there straining away inevitably comes up. This is actually difficult for me to answer with any scientific data, which is why I referenced my own results above. I genuinely don’t know what causes constipation in most people, and so can’t really explain in specific terms why it is that I don’t have any problems with it. In lieu of anything, er, solid, I’ll just speculate.

Googling around has revealed that constipation is actually not well defined and thus is difficult to diagnose and measure, let alone treat. Theories abound, most surrounding a lack of fiber or roughage to stimulate the bowel to move things along. This sounds reasonable, and since most people don’t devote a lot of time towards wondering about constipation, it’s not surprising that it has become so ingrained. But let’s think about that critically for a moment.

Fiber is, by definition, indigestible material. It enters your small bowel more or less intact, which triggers a complex response. Peristalsis, or the contractions of your bowel to move things along, is elevated when fiber is present. This leads to the logical conclusion that fiber helps move things along, and thus must be a good thing.

However, that hypothesis seems to rest on shaky ground: why is it that you need to move things along, exactly? Why would one assume that this is healthy, and not your bowel attempting to rid itself of an unwanted substance? It can’t be digested, after all. It stands to reason that your bowel would want to clear itself of something it can’t do anything with, and it further stands to reason that such a response is counter-productive. The purpose of your small bowel and colon is to absorb nutrients and water. Speeding things up doesn’t make any sense. This alternative explanation for fiber’s effects does not appear to have been considered.

Worse, fiber adds bulk to stools. This is considered a good thing, for reasons I cannot fathom but which probably would be readily acceptable to any male between the ages of 0 and 80. Pride in crap size and integrity is not uncommon. The damage and strain caused by a bulky stool, however, is left unconsidered. Your bowel must stretch and strain to push a huge mass down and out, which is difficult. Over a lifetime, this stretching of the bowel can prevent it from functioning properly, which is a boon for the producers of Metamucil and fiber supplements but really sucks for the poor person who has to take them.

“But don’t you have to move things along to keep your bowel clean?” This is a corollary to the meat putrefaction question I referenced earlier. Let’s first dispel a myth implied by this statement: your bowel is not, and never will be, “clean”. It contains huge amounts of bacteria and food in various states of digestion. If you are eating a standard fiber filled diet, mucous is being secreted to protect your delicate intestinal lining. Poop comes out of it. It’s not and never will be clean, at least not until they flush you out with formaldehyde before your funeral.

That aside, the idea that food just sits around in your bowels putrefying is somewhat absurd. Your body is designed to take in organic matter, break it down and absorb it. Your intestines have developed incredibly robust mechanisms to handle this task. Food never “sits” anywhere. It is first assaulted by hydrochloric acid and broken down, then bile salts to emulsify the fats, then a whole host of digestive enzymes which further break it down into components your body can absorb. In the absence of fiber or an overload of any given nutrient, your body then does exactly what it’s supposed to do and absorbs everything it can. Provided you aren’t eating a ton of fiber, you end up with a relatively tiny mass of undigested material to send down the pipe.

The problem, I believe, is that when people eat “healthy”, ie, avoiding fat and eating lots of carbohydrates, they inadvertently (or intentionally) consume a huge quantity of starch and fiber. The fiber bulks up and any undigested starch enters the colon to the joy of billions of anaerobic bacteria. They multiply vociferously and then die, adding their bulk to the stool. If you aren’t drinking enough water, or there’s some other disruption, you now have a huge mass of indigestible material stretching your bowel and defeating its ability to push things along. You are now constipated, in lay terms.

Notice how protein and fat don’t enter into the equation there. Protein and fats are almost completely absorbed. If they aren’t, the result is far from constipation. Fat doubles as a lubricant, which is quite effective at speeding things along and results in quite effective bowel movements. Worse still, if you are unable to absorb all your fat and protein, it’s likely that you are also failing to absorb excess enzymes and bile, which leads to a wonderful condition known as bile-salt diarrhea.

I assure you personally and with great conviction that neither experience qualifies as constipation.

The final claim I’d like to address is the myth that “meat takes a week to digest” or otherwise persists in your bowels longer than other foods. I don’t know how the hell whoever came up with this came up with it, and I don’t understand why people believe it. Again, let’s examine our friend meat. Meat consists almost entirely of protein and fat. In your stomach, these two macronutrients are broken down into smaller bits by hydrochloric acid. Pepsin attacks the proteins here as well. Bile salts are added in the duodenum, which emulsifies the fat and allow the enzyme lipase to attach to it. Various processes and other enzymes (proteases primarily) break the proteins down into amino acids. This slurry, called chyme, then slushes through your small intestine, being absorbed. The tiny amount of muscle glycogen you ate is quickly handled by amylase.

A very small part of any given piece of meat will be indigestible or fail to be digested. It will effortlessly pass into the colon and then out again sometime later. The stool will be very small, and since you don’t have a ton of food to push along, you might go a day or two in between bowel movements before you have enough in there to trigger a movement. Regularity is relative – you only need to crap often if you have a lot to crap out, which you don’t if you don’t eat indigestible materials. For the past week or so, I’ve gone to the bathroom far less per day than at any period in my memory. This is a gift, not a curse.

Most importantly, there’s nowhere for meat to “sit”. Your bowel is not a train station. It’s a slippery tube that, unless you’ve damaged yourself from years of eating too much fiber and carbohydrate and have something like diverticulitis or a fistula, does not have places for food to stick. I’ve got some great pictures of a bleeding inflammatory polyp if you want to see what a large intestine looks like.

Anyway, to summarize:

1) I have no constipation issues. On the contrary, I have no strain and go once every day or two.

2) Meat is almost completely absorbed in your small intestine and does not generate any significant indigestible mass for you to worry about.

3) Your intestine has evolved over several hundred million years to handle the problem of absorbing organic matter. Thankfully, our ancestors did not evolve anything as stupid as a place for food to sit for a week rotting. Let the cows do that, and then eat the cow.

4) If you want to constipate yourself, eat something that expands in your colon and which cannot be broken down by your body, along with some food that feeds your gut bacteria. Then go take several ox-bile supplements along with a big heaping pile of animal fat and experience the wonders of fatty bile-salt diarrhea. You’ll never forget.

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