Thursday, August 25, 2011

Adapted to Neolithic Foods?

A while back, Stephan Guyenet pointed to this excellent paper by lead author Pedro Carrera-Bastos (which included Loren Cordain and Staffan Lindberg), that I just got around to reading. It's pretty straightforward paleo stuff, neolithic foods are bad, modern industrial foods are really bad, modern lifestyles, inadequate sleep, smoking, stress, lack of vitamin D, really, really bad, etc.

But what's really interesting is Stephan's take on it. He writes:
One of the things I like most about the paper is that it acknowledges the significant genetic adaptation to agriculture and pastoralism that has occurred in populations that have been practicing it for thousands of years. It hypothesizes that the main detrimental change was not the adoption of agriculture, but the more recent industrialization of the food system. I agree.
Uhm, what? I just read the paper and I didn't see anything in it about acknowledging significant genetic adaptation to agriculture and pastoralism. I did see this:
This is why it is being increasingly recognized in the scientific literature, especially after Eaton and Konner’s seminal publication in 1985, that the profound changes in diet and lifestyle that occurred after the Neolithic Revolution (and more so after the Industrial Revolution and the Modern Age) are too recent on an evolutionary time scale for the human genome to have fully adapted.

In fact, despite various alleles being targets of selection since the Agricultural Revolution, most of the human genome comprises genes selected during the Paleolithic Era in Africa, a period that lasted from about 2.5 million years ago to 11,000 years ago.
What part of that indicates significant adaption to agriculture? The paper goes on to say:
Finally, the fossil record suggests that when hunter–gatherer populations made the transition to an agricultural pattern of subsistence, their health status and lifespan decreased.
As I've written before, Stephan has long been a proponent of traditional diets: neolithic foods are great, perhaps (probably?) optimal, as long as they are prepared in a traditional manner that minimizes anti-nutrients and such. The underlying assumption being that we are significantly adapted to these foods. The fact that Stephan is reading into this paper something that simply isn't written there is a classic case of confirmation bias, in my opinion. Stephan corresponded with Pedro on this paper and is consequentially cited by Pedro, so maybe I'm missing something, but I don't see a single sentence that indicates anything about significant adaption to neolithic foods.

I do see things like this:
The Agricultural Revolution began about 11,000 years ago in the Middle East, later spread to other regions of the globe, and drastically altered the diet and lifestyle that had shaped the human genome for the preceding 2 million plus years. Some of the more significant dietary changes were the use of cereal grains as staple foods, the introduction of nonhuman milk, domesticated meats, legumes and other cultivated plant foods, and later widespread use of sucrose and alcoholic beverages.

Nevertheless it was the Industrial Revolution (with the widespread use of refined vegetable oils, refined cereal grains, and refined sugars) and the Modern Age (with the advent of the “junk food” industry, generalized physical inactivity, introduction of various pollutants, avoidance of sun exposure, and reduction in sleep time and quality coupled with increased chronic psychological stress) that brought about the most disruptive and maladaptive changes, which may have serious pathophysiological consequences. For instance, chronic psychological stress, environmental pollution, and smoking are associated with low-grade chronic inflammation,
which is one of the main causes of insulin resistance.
I think every paleo/primal author/blogger would agree with this. Neolithic foods suck, additional modern/industrial foods (frankenoils, processed foods, etc) really, really suck. And a modern lifestyle, especially constant low-level stress, takes its toll. One can speculate all day long about what a pre-neolithic diet consisted of, that's not my point. As the paper points out:
Importantly, 11,000 years represent approximately 366 human generations, which comprise only 0.5% of the history of the genus Homo (Table 1).
Is 366 generations long enough to adapt significantly to neolithic foods? Mutation rates are a hot topic right now in biology and anthropology. They now appear to happen at a slower rate than previously thought. John Hawks wrote last year:
The study was by Jared Roach and colleagues, and as you might guess from my post title, the result was surprising. Previous work had suggested a human mutation rate around 2.5 x 10-8 per site per generation. The new study found less than half the expected number of mutations between these parents and offspring, an estimated rate of only 1.1 x 10-8 per site. 
Yesterday Hawks blogged about another paper that seems to back up a slower than previously thought genetic mutation rate:
A new paper in Nature by Zhe-Xi Luo and colleagues reports the discovery of a 160-million-year-old early mammal, Juramaia, which they attribute to the placental mammal lineage. The news aspect is that this extends the chronology of fossil placental and marsupial mammals (the sister clade of placentals) by some 40 million years. That's a big chunk of time, but it's a really nice fossil which seems pretty clear in its morphology.

I'm reading this closely because of the effect on the interpretation of mutation rates and the molecular clock. Obviously, if the earliest evidence for placental mammals used to be 120 million years ago, and now it's 160, that should affect the way we approach the genetic divergence of mammal lineages. In particular, when it comes to primates, some modern lineages are represented by fossils relatively early in the Cenozoic, suggesting that the common ancestor of all the primates may have been much earlier, deep in the Cretaceous period. 
On the other hand, maybe it just takes a few simple mutations to adapt to neolithic foods (prepared in a traditional manner, of course). It only took one mutation to turn off lactose intolerance, and that mutation has occurred in several populations engaging in animal husbandry independently.  But that mutation is to simply continue the production of lactase. Humans, like all mammals, are already ridiculously well-adapted to milk--at least their own species' milk, not processed, when in infancy--beyond that, things can get dicey. How many mutations and selection are necesary to adjust to a diet heavy in grains, legumes and other neolithic cultivars?

How well adapted we are to neolithic foods, which the paper cites as:
[...]cereal grains as staple foods, the introduction of nonhuman milk, domesticated meats, legumes and other cultivated plant foods, and later widespread use of sucrose and alcoholic beverages. [ed. I see sucrose as more of a modern/industrial era food]
Who knows, but one is probably better off avoiding them all as much as possible. I'm going to stick with this paradigm for now, I don't see the food reward/palatability hypothesis (FRH), especially as evoked by people with a strong bias towards "traditional" foods, as even coming close to supplanting it, or even supplementing it, at this point. Am I specifically going after Stephan Guyenet? Yes, I am. His blog is hugely influential and his recent "takedown" of the carbohydrate hypothesis and endorsement of FRH has been embraced by many influential bloggers. Maybe I'm just being reactionary, and I'm sure I'm guilty of my own confirmation bias, but I'm just not buying it.

Wednesday, August 17, 2011

Deeply Skeptical of Food Reward Hypothesis Pt. III: Psychology & Obesity

Deeply Skeptical of FRH Pt I
Deeply Skeptical of FRH Pt II

The thing I dislike most about the food reward/palatability hypothesis is that it sends us into the intangible. Obviously, things like addiction, pleasure, over-stimulation, etc, exist and they are ultimately tied up with things like free will. Unfortunately, this leads us to butting up against the mind-body problem, which I find aesthetically displeasing. FRH posits that obese people are hyperstimulated by food that tastes too damn good, and is too readily available. This seems too pat, too simplistic. And not in an Occam's razor sort of way. More like a "God does not play dice with the Universe" sort of way (yes, I agree with Einstein or more specifically Roger Penrose).

The problem with introducing psychological elements into obesity is that it creates a sort of chicken and egg ambiguity. The carbohydrate hypothesis (CH) goes something like this: people eat too many simple and complex carbs (sugar and starch), this leads to chronic insulin production and high blood glucose (BG) levels, this leads to insulin resistance and cuts off access to fat stores, glucose gets converted to fat but not vice-versa, high levels of BG cause glycation (glucose modification of proteins), the pancreas gets worn out, chronic inflammation follows, obesity, diabetes, heart disease, etc ensues. There are different variations of this but that's how I'd sum up CH off the top of my head.

The nice thing about CH is that there's no talk about willpower, beyond breaking one's initial sugar addiction and getting over an LC flu. But the addiction is simply and clearly defined. This makes CH aesthetically pleasing for me in an Occam's razor sort of way.

Stephan Guyenet argues that CH is complete garbage, of course. Andreas Eenfeldt argues that it more likely needs to be tweaked. Most of the cool kids seem to be on Stephan's "side". Yes there are sides and battle lines being drawn and epithets being hurled, feelings being hurt. Anyone who's ever read anything about the history of science knows this is pretty normal behavior. Controversy and disagreement are the lifeblood of healthy science. Institutionally biased funding and a deeply flawed peer-review system are not. To this day, Anglo-Saxon countries credit Newton with inventing calculus and continental European countries Leibniz.

Stephan believes that if one doesn't prepare most of one's food at home, using traditional cultural methods, one is inevitably at an increased risk of obesity and disease (that being the cold hard truth). There's a puritanism lurking there that I find too pat, too simplistic, not in an Occam's razor sort of way, but in a teenager's opinion of politics sort of way. It also smacks of noble farmer re-enactment (yeah paleos aren't the only ones who can get caught up in re-enactment). But most of all, there's a subjectivity that I think leads to non-testable hypotheses.

We can lock some obese people in a room and let them feed ad libitum on some bland high-carb substance that tastes like powdered milk, and they could lose weight. Which has apparently already been done (although I've not read the study) and is seen as a sort of smoking gun for FRH and against CH.

We could also lock a bunch of heroin addicts in a room and let them feed ad libitum on some bland high-carb substance that tastes like powdered milk. I would bet they'd all gain weight. What would we prove by this?

Patricia writes in the comments of the last post:
Palatable food does not make people overeat or get fat.  Hyperpalatable food does.  Many East Asian cuisines are palatable, yet the people who eat them are mostly of normal weight.
OK, but I think the distinction between palatable and hyper-palatable is subjective and scientifically useless. One can just as easily argue that these hyper-palatable foods contain NADs or are addicting because of CH. Or, as the Jaminets believe, that modern, and especially processed foods, are malnourishing hence leading people to overfeed in a craving for vitamins and minerals.

Ultimately, I find FRH to be scientifically ambiguous and unappealing. Something that sounds good, like eat less, exercise more, but doesn't offer up anything beyond intangible platitudes about food tasting too yummy mixed in with pre-modern (pre-industrial) neolithic idealism and re-enactment.

Tuesday, August 16, 2011

Deeply Skeptical of Food Reward Hypothesis Pt. II: Cry Havoc and Release the Paradigm!

Deeply Skeptical of FRH Pt I
Deeply Skeptical of FRH Pt III 

[Note: Stephan Guyenet didn't invent the food reward hypothesis, but his advocacy and approach are my only experience of FRH so this is what I will focus on]

A paradigm starts with assumptions (axioms) then builds upon those assumptions. If the basic axioms are flawed then the paradigm is inevitably flawed. This does not mean it is complete junk, though. Great paradigms will continue to work with limitations. Euclidean geometry assumes that parallel lines never cross (amongst other apparent flaws), but that doesn't apply in a Universe where space is warped by gravity. Euclidean geometry is still a damn good approximation of static geometry at the human level which is why it is taught in schools today, not to mention that it is an excellent way to teach reasoning through proof.

The basic assumption behind an evolutionary (paleo-type) diet is that we humans probably aren't very well adapted to more than small amounts of very recently (evolutionarily speaking) introduced agricultural products like grains. We are better off eating a diet that closely resembles our hunter-gatherer ancestors. What an ideal HG diet consisted of (and how much it varied between different groups) is a huge source of contention and supposition--whether or not it was low-carb (LC) or how much fruit it entailed, etc--but I think the basic axiom is solid. Is a diet we've been eating for many millennia a better nutritional fit than an agricultural diet introduced a few thousand years ago.

Stephan Guyenet's nutritional paradigm is a bit different. He has long been a fan of traditionally prepared foods. Very seldom does he mention evolution, he's more likely to mention indigenous peoples like the Kitavans.

I find Stephan's traditional foods paradigm to be on shakier ground than an evolutionary approach. Sure, traditionally prepared foods help to remove anti-nutrients, usually through fermentation (sourdough bread, kimchi/sauerkraut, miso, etc), but does that mean that these foods are optimal?

Reviewing a paper by Pedro Carrera-Bastos and colleages Stephan writes:
[...] One of the things I like most about the paper is that it acknowledges the significant genetic adaptation to agriculture and pastoralism that has occurred in populations that have been practicing it for thousands of years. It hypothesizes that the main detrimental change was not the adoption of agriculture, but the more recent industrialization of the food system. I agree.
Here's a key idea to a traditionalist approach to nutrition. That we are already significantly adapted to a neolithic diet (assuming your ancestors have been farming for a few thousand years).

Despite his credentials and the fact that he is an active researcher in the field, my impression is that Stephan wants to embrace a theory that fits his idea that traditional diets are ideal. That the modernisation of the food industry by creating increasingly palatable and available food is what has led to the obesity/disease epidemic. Stephan is not saying food reward/palatability is the only contributing factor just an important one. The most important one as far as I can tell.

This is a valid chain of logic:

--> Humans are adapted to traditional neolithic diets
--> Traditional diets are boring
--> Humans aren't adapted to the modern commercialisation and industrialization of food
--> Modern food is too palatable
--> To be healthy and thin eat traditional and boring food.

This cuts out the middleman of the carbohydrate hypothesis. Macronutrients don't matter, as long as one eats a traditional diet (with lowered palatability) everything will be fine.

It's a valid chain of logic, but I'm just not buying it. There are a lot of assumptions there I simply don't accept. I don't think humans are well adapted to neolithic foods, traditional preparation helps but doesn't help enough. I don't believe that modern food is too tasty and available I just think it contains a lot of crap. I think we all can agree we shouldn't be eating processed crap.

Stephan writes:

However, losing fat and getting healthy will require some effort.  What I've offered is a plan that puts the effort in food selection, rather than fighting the urge to eat more calories, which is typically a losing battle anyway.  It also does not restrict micronutrients, macronutrients or any other health-giving element of the diet.  If you think you will be able to find a way to lose fat and remain in long-term health while eating mostly commercially processed food (including restaurant food), you are fooling yourself.  Processed food is the main problem, and if there is a solution, it is to avoid it.  If you aren't willing or able to eat mostly home cooked food made from basic ingredients, as every healthy culture does, you will have to accept a higher likelihood of fat gain and disease.  That is the cold, hard truth.
Nope, I just don't buy into that.

We actually do prepare most food at home. But when we go out we pretty much eat the same thing we would eat at home, meat, fish, vegetables. Here's some pics of what we were eating at restaurants on our recent vacation to Croatia. I just don't believe eating extremely palatable food like that at a restaurant every day is unhealthy or is somehow less healthy than a boring traditional diet based on taro or rice. This large lunch was typically supplemented by some vegetables or maybe fruit in the evening, or in my case lots of traditionally prepared fermented grain juice. I did put on some weight but I'm pretty sure it was the beer.

Is this unhealthy because it came from a restaurant and is too palatable?

In part III I will discuss why I'm uncomfortable with the notions of addiction and psychology being brought into the equation.

Monday, August 15, 2011

Deeply Skeptical of Food Reward Hypothesis Pt. I: Playing Gotcha

Deeply Skeptical of FRH Pt II
Deeply Skeptical of FRH Pt III

There's been an enormous amount digital ink spilled in the last week or so regarding the Taubes/Guyenet dust up at the Ancestral Health Symposium. It mostly boils down to the carbohydrate hypothesis (CH) vs the food reward hypothesis (FRH).

I'm happy to see the waters stirred up like this and the fact that it has drawn people like Dr Kurt Harris and Dave Dixon at Spark of Reason down from Valhalla.

First of all, I'd like to talk about all the tools used to justify people's nutritional paradigms when arguing.

These tools are extremely blunt. To put it bluntly. They mostly boil down to these three things:
  • The evolutionary extrapolation approach (What would Grok do? What kind of animal has a digestive system similar to ours, etc). 
  • Nutritional studies from Pubmed et al.
  • Indigenous studies like the Kitavans.
These are all extremely blunt tools.

Perhaps the most tedious is the tossing around of nutritional studies to try and "prove" that LC is unhealthy or that fat is bad or whatever. It is pretty easy to go to these studies individually and find how flawed they are, and Peter at Hyperlipid is the king of this sort of thing. I've done it myself when I've had the time and inclination.

This game of gotcha is idiotic because these nutritional studies are, for the most part, deeply flawed. If they are funded by private industry they are considered ipso facto biased. So they are funded by governments that actively believe in the diet-heart hypothesis, and published in peer-reviewed journals where the peers actively believe in the prevailing conventional wisdom of the field. This all taking place in a field that is extremely murky due to the essential complexity of human biochemistry. In other words, a very blunt instrument indeed.

The problem, of course, is that we are stuck with these blunt tools, so we need to make do as best as possible until something better comes along. Nutritional biochemistry is in a very primitive state compared to something like physics. This isn't helped by the fact that entrenched institutional bias and a flawed peer-review system have hampered innovation and iconoclasm.

When optimal nutritional biochemistry is conclusively nailed down by deriving it directly from DNA (or something like that) at some point in the distant future--the equivalent of a physics theory of everything or correct quantum gravity as Penrose likes to call it--these blunt tools will be seen as laughably primitive but right now they are all we have, and one's food choices are literally a life-and-death decision.

My deep skepticism of FRH is from more of philosophical perspective so I won't be citing Pubmed studies or talking about the Kitavans. There are plenty of smart people skeptical of FRH way more qualified to do that than myself.

Saturday, August 13, 2011

Odds and Ends

The Environmental Working Group has just issued their "Meat Eaters Guide: Report" with a simple graphic for us idiotic omnivores with a penchant for animal flesh. Turns out the best thing for meat eaters to eat (who have a carbon conscience) are lentils, skim milk and  tomatoes. No references necessary since they are trying to SAVE THE FUCKING PLANET.

Meanwhile, I'm pretty fired up about the big Guyenet/Taubes dust-up and the reaction it has provoked. I have some strong opinions on this subject and I'm looking forward to airing them when time permits.

Friday, August 12, 2011

Screw The Cool Kids!

While all the hepcats were off at the Ancestral Health Symposium in some town called Los Angeles, we were having our floors redone here in Prague, which meant staying at a friend's gingerbread house.

My friend B has a tiny little house not far away, less than 10 minutes by car, but the quiet neighborhood is so different from our busy area that it is like traveling out to the countryside.

This should have been a pleasant interlude, but between being stuck inside due to the shitty weather, the unpleasant bed (a tired old futon of miniscule thickness), and Liam bringing home yet another cold from school it was kind of a living hell.You ever go camping but then you get sick, it rains the whole time and someone forgot the kerosene? That's what it was like.

OK, enough bitching.

I should've taken more pictures, because it is a pretty amazing little house and area. It's a cliché of what an American like me grew up thinking Europe was like. But between the raging cold and the sleep deprivation I was lucky to snap these. Was I bitching again, sorry.

Here's the street B lives on. As one might guess, there ain't a whole lot of motorized traffic going on here.

This is the front door. There is some ducking and weaving involved in trying to enter the house.

These stairs are at a 75 degree angle, really more of a ladder than stairs. No handrail of course, because that's not minimalistic enough for B. After falling and cracking a rib (twice!) B decided to put some sort of felt stuff on the steps. Every time I go up these stairs I feel like I'm climbing up to the bridge of a submarine.

B's balcony. I managed to take this picture during a rare interlude when the sun was actually shining. It took lightening quick reflexes. 

Obviously, the best thing to do when one has a tiny little house is to fill a third of the living room with a pool for fishes and turtles. There's a nice place for a reptile to sun itself there in the background. To get to the bathroom, one actually has to walk across a bridge (unfortunately NOT made of glass) over the turtle pool. I forgot to take a picture of that, damnit. The pool isn't big enough to put in sharks with frickin' lasers, but it has a sort of miniaturized James Bond feel about it. 

Opposite the stairs/ladder is this corner chair with hat and boot collection next to it. These low-slung chairs look cool as hell but aren't very practical for a tall guy like myself. Me and B are pretty much polar opposites when it comes to style vs practicality.

Lastly, I thought this was amusing. This long, long walkway leads up to the front door of a large villa nestled against a hill. I don't envy anyone delivering furniture to these people. Although, come to think of it, this place is way more accessible than our flat on the fifth floor with no elevator.

Wednesday, August 03, 2011

Predators and Projection

I grew up with plenty of dogs, especially one in college who accompanied me on many hikes and camping trips. Nowadays, we have four cats in our rather small flat. Both species are quite amazing in their own ways, but I think cats are more fascinating because they are much less like us humans than dogs.

Cats are pretty much at the apex of physical perfection.

As I see it, there are 3 kinds of mammalian predators:
  • Wolves--which specialize in endurance and intelligent cooperation 
  • Bears--which specialize in omnivorous flexibility and hibernation
  • Cats--which specialize in being incredibly bad-ass
Humans fall between the wolf and bear category of predator. We can hunt us down some ruminant using intelligence and cooperation, but we can also survive on berries, fish and root vegetables. Mostly, we get by with our brains which allow us to read and write blogs about other predators.

But cats are so well evolved that they don't need any of this other crap. They can't survive on any sort of plant based diet because they lack the ability to synthesize the essential amino acid taurine. And they don't care or need to work together (lions being something of an exception). Cats are the true mammalian predators.

While humans exist in a society based on cooperation and compromise, what people secretly yearn for is to be more cat-like. I offer as proof the extremely successful Hollywood obsession with superhero movies. What are all these superheros but the human incarnation of the felidae family?

Speaking of human incarnations of felids, Michelle Pfeiffer in a catsuit sends my testosterone levels rocketing to eleven:

The similarity of cats and imaginary superheros is left as an exercise to the reader.