Follow-up on Farewell to Paleo, and Comments on Confirmation Bias

Seems that many people did not understand my Farewell to Paleo post.

I wrote that blog after ~14 y of tinkering with paleo principles under the common assumption that we (humans) are fully adapted to a meat-based diet, i.e. that a 'paleodiet' should supply most of its energy and protein from meat and fat.

My experience didn't confirm this belief.  Tracy and I, and many of my clients and students,  had increasing problems with inflammation, accumulation, congestion and stagnation while eating a meat-based diet supplying ~50-60 percent of calories as fat, despite avoiding the dreaded neolithic foods and also eating a large amount of produce.

It seems paleo has for many people become synonomous with meat-based, high-fat nutrition, and so many 'paleo' and 'primal' people are also endorsing and including processed meats (bacon, sausages, etc.) or dairy products (cream, butter, etc.), that it has become little more than a kind of rehashed Atkins.

I regret having contributed to that.

It is to that 'paleo' that I said good bye.

After looking at research ignored by advocates of meat-based and high-fat nutrition, thinking things through, and experimenting a bit, I now have a different understanding of paleo diet.  I leave the details for the follow-up on the Ancestral Health Symposium.

For now, in case you didn't notice, people in the media have already pegged 'paleo' as rehashed Atkins in the 'caveman diet' guise.  If anything will destroy paleo, it is this.

Now, I have also noticed that people in the paleosphere have taken to accusing me of confirmation bias.  I find that very rich indeed.


Confirmation bias means only seeing evidence that supports your beliefs, and not seeing evidence that contradicts your beliefs.




In the paleo- and low-carbo- spheres, confirmation bias looks like this:

• Only focusing attention on or considering as important those physiological features that make humans different from other primates, and ignoring the many nutrition-related physiological features that humans share with other primates.

• Only seeing/accepting evidence that meat-eating has benefits, while ignoring, refusing to accept, or denying good evidence that meat-eating can in some quantities and contexts be harmful.

• Only seeing/accepting evidence that saturated fats are neutral or beneficial, refusing to accept good evidence that excess dietary SFs have harmful effects in certain quantities and contexts.

• Only seeing/accepting evidence that unsaturated fats are harmful, while ignoring contrary evidence.

• Only seeing/accepting evidence for the positive effects of cholesterol, while ignoring a mountain of contrary evidence showing adverse effects of excess dietary and serum cholesterol.

• Only seeeing/accepting evidence that grains and legumes are harmful, refusing to acknowledge evidence that they can be neutral or beneficial.

• Only seeing/accepting evidence that 'vegetables are useless or unnecessary,' while refusing to acknowledge evidence that they have benefits.

• Only seeing/accepting evidence of potential harm from eating nuts (e.g. so-called antinutrients), while ignoring or belittling evidence that they provide benefits.

And so on.

I was caught up in that confirmation bias for quite a while.

But as I have increasingly broken away from it, and written blogs discussing evidence contradictory to the popular 'paleodiet' and high-fat/low-carb perspectives, I get attacked for confirmation bias?

It reminds me of the old adage:  When you point a finger at someone else, you have several pointing back at yourself.

As I said in the 'Farewell to Paleo' post, I said farewell after tolerating cognitive dissonance for too many years. 

I forgot to write that I came to meat-based 'paleo' diet after ~14 years eating a primarily vegetarian, grain-based, macrobiotic diet.  That diet, combined with herbal medicine, had provided me with many health benefits, not the least of which being control of my constitutional tendency to respiratory allergies and inflammatory skin conditions (diagnosed as eczema and psoriasis, labels I don't necessarily accept).

As a graduate of the American Academy of Nutrition, and after 14 years as a vegetarian, I could martial plenty of evidence for a vegetarian, low-fat diet.  When I encountered the evidence for meat-based 'paleo' I of course found it was totally contrary to my expectations,  but after serious consideration it appeared strong enough to me that I could no longer ignore it, so I switched from macrobiotic to meat-based, intellectually convinced that the change might improve my health even further than I had gotten with macrobiotics.

I'm not one to try things lightly then dismiss them.  If I think 'paleo' should work, and I find glitches, I will go back to re-evaluate the basics.  If I still think the basic plan is correct, I will try some adjustment within the framework, like decreasing protein and increasing fat, or some other.  I might be stubborn, but I don't give up on what I think is correct until I seem to have exhausted all possible variations, OR I notice that I am ignoring evidence that the basic plan has some important flaw.

When I see evidence contrary to my expectations repeatedly coming to my attention, I can't keep ignoring it, or explaining it away, to satisfy my preconceptions.

In my life, not only me, but people I love were putting into practice the ideas that increasing intake of meat and saturated fat will improve health, and they were suffering:  Gaining body fat, rising blood lipids, congestion, malaise, low energy, etc.

Meanwhile, I could no longer ignore or consider invalid all of the literally thousands of epidemiological, clinical, and animal studies linking modern degenerative diseases to excessive intake of meat and fats, including saturated fats, in modern nations.

Nor could I continue to ignore or belittle all of the hundreds of well-designed studies showing positive health effects of increasing the plant: animal ratio or particular plant components of modern diets.

And that's why I finally said farewell to meat-based, high-fat 'paleo.'   I just couldn't keep ignoring evidence hitting me in the face, contradicting my belief that a diet providing a high proportion of energy from meat and fat  promotes health.

I could no longer accept a flat earth, when the evidence for a sphere hit me in the face.


Which led me to realize, that if the paleo principle is correct, there must be some evidence for strong human adaptation to plant-based diets that the meat-based paleo crowd has either overlooked or ignored.

And I think I have found that evidence.  

Its complicated.  The effect of any nutrient or food on human health depends on quality, quantity, and context of consumption. 

I can no longer allow myself to fall into simplistic thinking like  'meat good, grains bad,' 'fats good, carbs bad,' and such. 

Meat can have benefits in some quantities, qualities, and contexts, and cause harm in other quantities, qualities, and contexts.

Ditto for fats, carbs, grains, everything.

Done with nutritional dualism. 

Everything is relative.

Anything can be medicine or poison, depending on quality, quantity, and context.