Kurt G. Harris MD

PāNu means paleonutrition. The "paleo" here signifies "old" and not necessarily paleolithic. The PāNu approach to nutrition is grounded on clinical medicine and basic sciences disciplined by knowledge of evolutionary biology and paleoanthropology. The best evidence from multiple disciplines supports eating a pastoral (animal-based) diet rather than a grain-based agricultural one, while avoiding what I call the neolithic agents of disease - wheat, excess fructose and excess linoleic acid.

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Thursday
Jan272011

More N = 1

Reader Dallas Hartwig makes some comments in italics, and my responses are in roman.

Thanks for yet another thought-provoking article. I appreciated the cordial-ish exchange on Robb's site, and (unlike some other commenters there) I'm completely good with simple disagreement. Shoot, why does everyone need to be "right"? I have a modest body of experience and education, and both of those are constantly growing. And, like other folks that you've posted about, my position on some things sometimes shifts over time as my understanding and experience changes me. On other things, my current position stays firmly where it has been for years. Anyway, on to my actual point.

I think that there should be a marriage of peer-reviewed science and personal/collective experience.

You say that as if it is something I might disagree with. I would not disagree.

That partnership allows for real-time improvements, instead of waiting for the consensus of published, peer-reviewed research to indict or acquit one particular food or food group.

I think where we disagree is on how robust the evidence should be before an athletic trainer or a physician tells someone that as a rule they can no longer eat a whole category of food. I feel the case against wheat is an order of magnitude more convincing than for cream and butter and non-soy legumes. So I would be loathe to start with that a proscription, just like I am loathe to say don't eat beef because some people have a beef allergy (as discussed on the thread at Robb's) I am not saying don't pre-judge without a randomized trial, but I am saying that the case against these latter foods is not as defensible as wheat, etc.

The solo act of a science-only approach, while it avoids the (valid) placebo concern, spawns extended periods of time (decades!) with no definitive answer for the masses that are so, so sick these days. I agree with you on the general reduction (or complete omission) of wheat/gluten, fructose, and LA, but I'm not clear on how both you and I concluded that these things are less-than-awesome, since scientific research is far from "complete and conclusive" on even these topics.

I never said "complete and conclusive" nor have i advocated a solo act of only peer reviewed science- those are your words. I said the scientific reasoning should be sound and there should be evidence. And then N=1 should be applied with caution, with emphasis on objective measures of health. This is based on my 20+ years of experience as a physician, and how relying on subjective impressions can be very hazardous.

So while there are some publications that suggest that most folks would do better without these, we've "married" that incomplete scientific evidence with experience, and forged our opinion, right? I think the general dismissal of individual experience as a valuable indicator leaves the general public open to more "science-based" recommendations like the Food Pyramid, etc.

You are misunderstanding what I am saying. If you re-read it, you will see it is not a general dismissal at all. It is a cautionary warning. When we come up with something like my 12 steps or your diet rules, we are indeed making a heuristic that is similar to the food pyramid. We indeed do it on incomplete information, and so should be pretty conservative in what we proscribe - so to avoid it being rightfully dismissed as scientifically indefensible, like the food pyramid.

......I guess I feel like the complete reliance on published literature to support one's position is unhelpful for folks desperately trying to sort through all the conflicting recommendations.

Sometimes we must sacrifice helpfulness and convenience for accuracy.

Robb's "try it and see" approach was, I suspect, a response to the constant rebuttal of some scientific suggestions (if not conclusions) that he drew from his education and research.

I don't think it's at all detrimental to perform a case study of yourself by removing foods, reintroducing them, and evaluating how you do.

Thinking that this is more meaningful than it really is what is detrimental. Not the doing it, just thinking you have really proved something. Like thinking wheat is harmless if you can eat an entire pizza in one sitting and have no ill effects. I can do this no problem. OTOH, if I eat too much onion I feel ill from the FOS fermenting in my gut. Does that mean pizza is good and onions are bad*? Surely you can see the deeply flawed logic in this kind of self-experimentation.

However, I do think that waiting til all possible doubt has been removed by scientific study could have some tangible consequences. I, personally, would rather err on the prudent side, even if that's construed as a precursor to paranoia.

You already know I have never advocated removal of all possible doubt. I am a neuroradiologist. I deal with Baye's theorem and conditional probabilities for a living. And I think that messing with people diets (and consequently their heads) is serious stuff, so I prefer to err further on the side of being more sure that there is a sound case against a proscribed food.

It's not paranoia I'm worried about. It is accuracy and the long-term defensibility of what is being recommended.

Thanks for the dialogue.

You are welcome!

 

* For newbies, the answer is the pizza (wheat flour) is bad even if I feel fine, and the onion is harmless even if I am doubled over with temporary gas pain.

Reader Comments (3)

Weird, I was just thinking about this yesterday at lunch.

This reminds me of an episode of The Venture Brothers (animated series), where one of the brothers says to the other, "You know, technically, putting plastic dinosaurs in water until they get really huge isn't 'doing science'".

Science at its core is testing ideas by experiment. This is seductively simple; anyone can run an experiment, and Paleo usually is served up with all sorts of "science says so" stories, so of course we all run off and start doing experiments on ourselves. We stop eating food, we add food, and in our minds this is "n=1 experimentation/science!".

N=1, though pejorative, is starting to strike me as a misleading term because it implies some level of rigor which is totally absent from the usual random diet experience. An N=1 experiment would rigorously define the measures of success or failure, the conditions of the test, and control (as much as possible) by shifting as few variables as possible. But that's not what we do; we change our diets according to random whim and often incoherent philosophy, then draw unsupported conclusions from our fragmented data.

I ate an all meat/VLC diet for a year to see if it would make my Crohn's get better. By all appearances (and how I feel) it did. But if I want to start calling this science, what I really should be doing is finding some food I would predict would bring my Crohn's back and eat it for a couple months. And then repeat that pattern a couple of times to see if I can reliably induce the disease and put it into remission, keeping my diet as simple as possible the whole time. Then I might be allowed to call it "N=1". But until then I think I'll just call it an experiment.

Good to have you blogging again doc!

January 28, 2011 | Registered CommenterPhil W

Doc,

I'll take it as a compliment that you thought my comment worth replying to. In essence, our general disagreement (I think) lies in how large the sum of science + experience needs to be before it crosses a threshold and becomes a "sound case". And, if I've understood your recommendations correctly, our specific disagreement is over dairy proteins - I see lactose tolerance/intolerance as a minor issue, and I mentioned that I have no concerns with dairy fats. So despite our (minor) differences, I've enjoyed the discussion, and I feel it's a net positive experience. I hope you feel the same.

January 28, 2011 | Registered CommenterDallas H

Dallas

Every movement needs a cranky skeptic. Sometimes that will be me. I have no doubt you are helping a lot of people. The campaign against the NAD has some good soldiers : )

January 28, 2011 | Registered CommenterKurt G. Harris MD

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