Twitter

The sous vide time commitments have put a real hickey on my reading.  I’ve probably read less over the past four months than in any four month period of my life.  Instead of five or six books per week, I’m down to about two or three max.  I hate it.  I’m trying to keep up with my daily medical/scientific journal trawl, but that has even slacked off a bit.  When I do find something of interest, instead of blogging on it as I used to, I stick it up on my Twitter page.  I probably post 10-15 times per day on Twitter, so if you want to keep up on a moment-by-moment basis, follow me on Twitter.  If you have a problem thinking of yourself as a Twitter person, give it a try.  I dipped my toes in the Twitter waters with great hesitation, and now I love it.  I’ve found it extremely valuable because I find all kinds of new stuff daily.  You’ve got to be careful who you follow, however, or you can waste a ton of time.  If you get started, start following people who provide you with information you can use.  I avoid following people who do nothing but tell me what they ate for breakfast that day or what movie they’re going to see that night.  Sign up an give it a go. You don’t have to write anything (or tweet, as it’s called) if you don’t want to.  You can simply lurk and be the beneficiary of a ton of good info.   The Twitter people take you by the hand and get you squared away.  It takes all of about two minutes – if even that.  Literally.

Comments

I have fallen way, way behind on dealing with comments.  As I wrote a while back, I had to stop answering individual comments, and I’ve pretty much stuck to my guns on that.  Problem is, I had about three hundred comments stacked up before I started doing that.

When comments come in and I post them, they go up in by date.  So back when I was spending half my day dealing with them, I would often come across a comment that required some thought and a detailed answer.  If I didn’t have time to deal with it right then, I put it off until later.  Often when later came, I had 20 or 30 more that came in after the one requiring the time.  I didn’t want to answer those and put them up ahead of the one I hadn’t answered, so I simply didn’t deal with any of them.  Now I’ve got about 340 of them stacked up and it gives me heartburn whenever I even get on my blog administration screen.  The sad thing is that some of these comments go back months and months.

I’ve been wracking my brain trying to figure out what to do with them, and I’ve finally come to a decision.  I’m simply going to post them as they are.  I’m going to post about 30 of them per day until they’re all up.  Why not all at once?  Because I know many of you are set up to get comments emailed to you when I post them.  I don’t want to clot email accounts with 340 emailed comments all at once, especially since some of these comments are lengthy.  So, I dole them out over the next 10 days or so while keeping up with the new comments as they come in. I won’t start this process for a few days to get those of you who don’t want even 30 of them a day coming in to unsubscribe.

Since many of these hoarded comments contain very good questions, they are a trove of subjects for future blog posts.  As I post them, I’m going to reread them and clip those that would make for good posts into Evernote or my new favorite plaything DEVONthink that I’m just starting to feel my way along with. (See this great Steven Johnson (whom I follow on Twitter) article about the virtues of DEVONthink.)  After I’ve got these blogworthy comments in a format in which I can find them instantly, I’ll start working through them and posting.

Bloggers and the Federal Trade Commission (FTC)

I don’t know how closely blog readers attended to the recent announcement by the FTC that they were going to start riding herd on bloggers, but the bloggers went ballistic.

Among its other duties, the FTC patrols the universe of advertising in this country looking for anyone or any company engaging in, as they term it, deceptive practices.  In other words, the FTC is on the prowl seeking out advertisers who make false claims in order to stop them and punish them.  Which all sounds good in the abstract, but in reality is a whole other story.

As I pointed out in an earlier blog, it’s a valuable exercise to read Kevin Trudeau’s first book to see how the FTC operates.  The nutritional and health information he presents is total garbage, but his description of the practices of the FTC is right on the money. (I’ve got to admit that some of the nutritional and health information presented in Trudeau’s first book (the only one I’ve read) is accurate, but I write that off to the law of averages.  He presents so much information that odds are some of it just happens to be true.  So, if you read the book and come across something that is nutritionally accurate, don’t write me about it.  I know a few things are there, but not enough to justify reading the book other than the first part, which is an excellent treatise on the FTC.)

The FTC has the power to absolutely ruin anyone and/or any company it chooses to go after.  If you read the first part of Trudeau’s book, you’ll see how.

So, the FTC opined that they planned on monitoring bloggers to see if they disclosed the fact that they were paid to do reviews on products.  Apparently, many bloggers make money by doing paid reviews on products without disclosing such, and the FTC doesn’t like it.

I’ve never reviewed products for pay, but I have read enough about it to know how it works.  Companies provide bloggers products, then pay these bloggers for reviews of the products.  I guess the fact that bloggers are given the products and possibly paid for the reviews as well might induce them to write positive reviews of products that they thought sucked.  And I assume that’s what the FTC is concerned about.

The FTC’s actions certainly got the blogosphere in an uproar.  So much so, in fact, that the FTC started to crawdad, which I never thought would happen.  Just goes to show that if you turn the spotlight of public awareness on even the most aggressive and powerful of all government agencies, you can get results.

Not that I fear the FTC on this (at least not at this point), I’ll go ahead and disclose where I get dinero from this blog.  Virtually all of the money that comes to me through the blog comes from readers buying products through Amazon.com.  When they buy a book I recommend or go through one of the book thumbnails of Protein Power or the 6-Week Cure up at the top right or any of our other books I have up on the site, I get a little bit of lucre for it.  And I get a little more if they buy anything else after entering Amazon through one of the portals in this blog.  In a good month, it’s enough to cover my hosting and web guy expenses; in a bad month (as this one is turning out to be), it’s about enough to cover the hosting of the site and maybe an hour or so of the web guy time.

Google ads

I get a little income from Google ads, but I’m trying to get them off the site.  I’ve had several web guys working on the site over the years, and I guess code for these Google ads is stuck all over the place.  I get rid of them in once place, it seems they pop up somewhere else.  When I had Google ads everywhere, I made about $150 per month, which, in my opinion, isn’t enough to justify tacky-ing up the site with a zillion ads.  Plus, I don’t have time to go through and spend time trying to figure out which ads to block.  Many people, I’ve learned, don’t realize that these ads aren’t part of the site, and they wonder why, when I’ve just spent 2000 words bashing statins, an ad for a statin pops up.

A while back I was having lunch with Mark Sisson of Mark’s Daily Apple when he asked me what kind of a deal I had going with Atkins Nutritionals.  I told him I didn’t have any kind of deal going with them whatsoever.  I asked him why he asked.  He told me that he gets my blog posts by email, and that at the bottom of each one is a banner ad from Atkins.  I was embarrassed to say that I didn’t even know you could get the posts by email and that I didn’t have a clue why the Atkins ads were there.  I went home and pulled up the blog (I usually never look at the actual blog – only the admin page), and sure enough, there was a way I could get the posts by email.  I signed up to get my own posts, wrote one, and sure enough, here it came with an Atkins ad at the bottom of it.  I thought I had it all taken care of, but I just looked moments ago and there is still a banner ad at the bottom of the emailed post.  I’ve added it once more to the list of things to have my guy deal with when I get with him on Monday.

Book recommendation

While on the subject of Amazon.com, books and book recommendations, I might as well recommend one.
I finished a terrific book not long ago called A Colossal Failure of Common Sense: The Inside Story of the Collapse of Lehman Brothers. As the title implies, this is a treatise about the fall of the House of Lehman, one of the country’s oldest investment banks, and is written by one of the vice presidents who names names and points the finger.

Not only is this book chock full of great information about how Lehman Bros, Bear Stearns, Goldman Sachs and others operate, it is extremely well written.  The ‘author’ realized he didn’t have the skills to tell his own story in a readable manner, so he hired a writer.  But he didn’t just go out and hire one of the non-fiction write-for-hire folks that are swarming around out there, he hired Patrick Robinson, a best-selling thriller writer.  As a consequence, the book is absolutely gripping. Not only do you learn a ton about how the financial crisis developed, you learn it in a gripping, racing-through-the-pages fashion.  You’ve heard people say about certain books that they read like a novel.  Well, this one does.  I had real trouble putting it down.

After reading this book, you will know exactly why we’re in the boat we’re in now and will be stupified at the mismanagement at the top.  As I read through and learned about the perfidy of Moody’s, Standard & Poors, and the other financial rating outfits that gave the most worthless financial instruments triple A ratings, I was stunned that these companies hadn’t been prosecuted.  Without their complicity, the whole house of cards couldn’t have been erected because no one would have purchased the products.  I was interested to read in today’s Financial Times that at least  Ohio is going after them.  I suspect Ohio won’t be the last.  According to the author, these companies made billions while failing to do their due diligence before passing out AAA ratings like they were candy at Halloween.

Not long after I read the book, I came upon a piece by Calvin Trillin in the editorial section of the New York Times that summed up the situation nicely.  The problem was the enormity of the amounts of money waiting to be made drew smart people to Wall Street.  A funny but insightful short essay.

After you read the book and Trillin’s piece, take a look at this video I posted about a year ago.  It will make it all that much more funny.  And sad.

The 6-Week Cure blog

All I can say is that it’s about up.  And apologies for not having it up sooner.  I hope we’ll have it operational this week and populated with a few posts.

Another vegetarian myth

I wrote in a bookish post (or maybe in answer to a comment on a bookish post – I can’t remember) a while back that I had read most of the mystery novels out there and was looking for a new series to sink my teeth into.  Someone suggested the DI Charlie Priest mysteries by Stuart Pawson.  I got one and liked it, so I’ve been motoring through those as time allows.

The last one I read was Deadly Friends about a murdered doctor, a serial rapist and a host of other minor villains. At a point about midway through, DI Priest and one of his underlings are walking around scoping out a pharmacy prior to entering to get info about the dead doctor.  All these books – at least the four or five I’ve read so far – are written in the first person, so everything is from Priest’s perspective.  Here’s what he says:

We completed our circuit of the block.  Passing the back of the butcher’s I tried not to inhale and wished I had the willpower to go vegetarian.  Trouble is, I like my steaks.

AAARRRGGGHHHH!  Even in mystery novels I’m being reminded of how deep the vegetarian mantra has wormed its way into our collective brains.  How many times have we all heard variations on this theme?  One of the ideas the vegetarian movement has managed to get firmly implanted in the minds of many is that vegetarianism is a more healthful way to eat.  I’ve heard numerous people wistfully say they really would like to be able to follow a vegetarian diet because it’s so much more healthful, but they just like meat too much to do it.

The truth is, as we all know, that vegetarian diets are decidedly less healthful than diets containing animal protein. But the great unwashed masses don’t seem to have figured this out.

But I’ve got to hand it to the vegetarian brigade: they’ve managed to successfully propagandize most of the population.  And they’ve done so without any real science behind them.  The most they can point to is a sheaf of observational studies that don’t prove squat.

The low-carb/Paleo movement, on the other hand, is producing more data almost daily that a lower-carb, higher-fat, higher-protein diet is infinitely better for a majority of the population.  But, we don’t get the message out as well as the other side does, I suppose.  I went to a Borders Books the other day and found an entire collection of free booklets written for children telling of the horrors of factory farming and encouraging them to go vegetarian.

We are starting to make some inroads into this nonsense, however, with the help of some former vegetarians who have seen the error of their ways.  If you haven’t read Lierre Kieth’s book yet, add it to your Christmas list.

I’m girding my loins for all the hostile comments I’m sure to get from angry vegetarians.  These comments will be from vegans telling me how healthy they are and how many miles they can run and how they could kick my butt in any endeavor I might wish to engage them in.  And they’ll reference the idiotic China Study and a host of other meaningless observational junk.  But wait.  I don’t have to gird my loins.  I’m not dealing with these comments any more.  I’m just posting them as they come in.  Give it your best shot.

To see under what conditions our genome developed, read on.

The hunter-gatherer lifestyle

Just to wrap this long, meandering post up, I want to end with a link to a great article in the December 2009 National Geographic.  And to bring this post full circle, I’ve got to let you know that I found this article on Twitter.  I wouldn’t have discovered it otherwise. At least not as quickly as I did.

The long article is about the Hadza who follow a hunter-gatherer lifestyle in remote Tanzania.  The area the Hadza roam is being encroached upon by all kinds of agricultural and tourist businesses, and the author doubts these indigenous people can maintain their lifestyle for much longer.
The men hunt and the women gather.  The Hadza went on a nighttime baboon hunt and took the author along.  His account of the hunt makes for a riveting read.  Once killed, the Hadza haul the baboon back to what serves as a camp and prepare to serve it up.  I’ll leave you with the author’s description of the meal.

Ngaola skins the baboon and stakes out the pelt with sharpened twigs. The skin will be dry in a few days and will make a fine sleeping mat. A couple of men butcher the animal, and cuts of meat are distributed. Onwas, as camp elder, is handed the greatest delicacy: the head.

The Hadza cooking style is simple—the meat is placed directly on the fire. No grill, no pan. Hadza mealtime is not an occasion for politeness. Personal space is generally not recognized; no matter how packed it is around a fire, there’s always room for one more, even if you end up on someone’s lap. Once a cut of meat has finished cooking, anyone can grab a bite.

And I mean grab. When the meat is ready, knives are unsheathed and the frenzy begins. There is grasping and slicing and chewing and pulling. The idea is to tug at a hunk of meat with your teeth, then use your knife to slice away your share. Elbowing and shoving is standard behavior. Bones are smashed with rocks and the marrow sucked out. Grease is rubbed on the skin as a sort of moisturizer. No one speaks a word, but the smacking of lips and gnashing of teeth is almost comically loud.

I’m ravenous, so I dive into the scrum and snatch up some meat. Baboon steak, I have to say, isn’t terrible—a touch gamy, but it’s been a few days since I’ve eaten protein, and I can feel my body perking up with every bite. Pure fat, rather than meat, is what the Hadza crave, though most coveted are the baboon’s paw pads. I snag a bit of one and pop it in my mouth, but it’s like trying to swallow a pencil eraser. When I spit the gob of paw pad out, a young boy instantly picks it up and swallows it.

Onwas, with the baboon’s head, is comfortably above the fray. He sits cross-legged at his fire and eats the cheeks, the eyeballs, the neck meat, and the forehead skin, using the soles of his sandals as a cutting board. He gnaws the skull clean to the bone, then plunges it into the fire and calls me and the hunters over for a smoke.

In April 1995 an article appeared in the journal Current Anthropology that was an intellectual tour de force and, in my view, an example of a perfect theoretical paper.  “The  Expensive-Tissue Hypothesis” (ETH) by Leslie Aiello and Peter Wheeler demonstrated by a brilliant thought experiment that our species didn’t evolve to eat meat but evolved because it ate meat.

The ETH is an example of the kind of scientific detective work that I love.  In fact, this paper is one of my all time favorites.  (An amazing bit of trivia about this paper is that it almost didn’t get published.  I had the opportunity to talk with Leslie Aiello at a meeting a few months ago, and she told me that the journal was reluctant to publish the paper because they thought it too technical for their readers.  I suspect they also found it too controversial.  Now I’m sure they’re glad they published because I would imagine it is the most cited of all the papers ever published in Current Anthropology.)  The authors methodically lay the scientific foundation for their experiment, then, like Sherlock Holmes, progress step by step, accumulating little pieces of data until they reach the ineluctable conclusion that meat eating made us human. I would like to walk us all through their thought processes as laid out in their brilliant paper.

Let’s start with the problem.

For years anthropologists have speculated about why humans developed such large brains so quickly – from softball size to what we have now in just a short 2 million years.  Below is a graphic showing hominid/human brain growth over time.

A number of hypotheses have arisen to answer this question.  Some say that humans developed large brains because they had to contend with problems involving group size, others posit that large brains came about as a consequence of developing complex foraging strategies, others yet say the development of a social or Machiavellian  intelligence was the driving factor.  And even others say that the complexities of learning to hunt expanded brain size.

Any or all of these hypotheses may be valid, but the problem isn’t really as much a matter of why as it is a matter of how.  Other primates deal with groups and have complex foraging strategies; and many deal with social problems within their groups, and some even hunt.  Yet they still have small brains.  (Granted, their brains are larger for their size than those of other mammals, but primates sport small brains as compared to humans.)  How did the human brain grow?

This isn’t an easy question to answer because of the thermogenics involved.  Brains consume a large amount of fuel and, consequently, throw off an enormous amount of heat for their size.  The metabolic rate of brain tissue is nine times that of the average of  the metabolic rate of the rest of the body.

So what? you may say.  So we’ve got a big, hot-running, energy-burning brain.  What difference does that make?  It’s reflected in our overall metabolic rate, right?  Well, sort of, and therein lies the crux of the problem.  As we will see below, our total metabolic rate – even with our huge brains – is the same as that of any other animal our size. Or to say it another way, animals our size with much smaller brains have the same metabolic rate that we do with our huge brains.  This fact was the starting point for the authors of the ETH.  So let’s start there as well.

In keeping with a great scientific tradition, Aiello and Wheeler were able to see what they saw because they stood on the shoulders of giants who came before them.  In their case the giant was Max Kleiber, an animal physiologist working at the University of California at Davis, who published a groundbreaking paper in 1947 and a scholarly text titled The Fire of Life in 1961.  Kleiber’s work involved the meticulous measurement of the metabolic rates of numerous animals, including humans.  As he plotted the various metabolic rates, he discovered an extremely strong correlation between the mass of an animal and its metabolic rate.  Kleiber found that this relationship held constant across numerous species.  His October 1947 paper in Physiological Reviews simply titled “Body Size and Metabolic Rate” was a classic.  By using the equations Kleiber worked out, the metabolic rate of virtually any animal could be determined simply by knowing the animal’s body size.  Or, as Kleiber put it in the paper:

Does a horse produce more heat per day than a rat or do some rats produce more heat than do some horses?  Almost anybody who understands what is meant by “heat production per day” will not hesitate to give the correct answer and will even be convinced that the daily rate of heat production of men or sheep is greater than that of rats, but smaller than that of horses.  Thus most people (among those who understand the question) are convinced that in general the bigger  homeotherms produce more heat per day than the smaller homeotherms, that, in other words, the metabolic rate of homeotherms is positively correlated to body size.

The answer to the next question: “does a horse produce more heat per day per kilogram of body weight than a rat?” requires some biological training.  Most biologists, however, will not hesitate to answer that the rate of heat production per unit body weight of the big animal is less than that of the small animal.

The positive correlation between metabolic rate and body size, and the negative correlation between metabolic rate per unit weight and body size, establish two limits between which we expect to find the rate of heat production [basal metabolic rate] of a horse if we know the rate of heat production of a rat.  We expect the metabolic rate of the horse to be somewhere between that of the rat, and that of the rat times the the ratio of horse weight to rat weight, provided of course that we do not regard these two correlations as simply accidental.

If we are firmly convinced that the metabolic rate of horses, and other homeotherms of similar size, is never outside these two limits, then we admit to recognize a natural law between body size and metabolic rate.

This natural law, carefully calculated by Kleiber, is now known as Kleiber’s law.  Below is Kleiber’s law graphed out by him as it appeared in his seminal paper.  And this is exactly as it appeared in the journal, but with the addition here of colors for better legibility.  Since their was no Excel nor graphics software in Kleiber’s time, the graph was hand drawn and appeared in the pages of Physiological Reviews as such.  How times have changed.

As you look along the line running from lower left to upper right, you can find rats and horses and a host of other mammals including humans.  Over the years, mammals that Kleiber didn’t have the opportunity to work on have been measured, and they all fit nicely along Kleiber’s line, following Kleiber’s law.  Because of this tight correlation, Kleiber’s equations can be used to precisely estimate the metabolic rate of any animal just by knowing its size.

Aiello and Wheeler used Kleiber’s law as the jumping off point for their grand thought experiment.

Since all animals measured have conformed to Kleiber’s law, Aiello and Wheeler postulated that animals now extinct – including our human and pre-human predecessors – would have fallen along the same line. Using skeletal remains paleontologists have been able to calculate body sizes of extinct animals along with pre-Homo and early-Homo species.  Then using Kleiber’s law, it is possible to closely estimate the metabolic rates of these creatures.  And here’s where it gets interesting.

According to Kleiber’s law, an australopithecine weighing 80 pounds would have the same metabolic rate as a human weighing 80 pounds despite the disparity in brain size between the two.  The much larger brain of the human would have 4-5 times the metabolic rate of the brain of the australopithecine, yet would have the same overall metabolic rate.  What gives?

That’s precisely what the authors of “The Expensive-Tissue Hypothesis” wondered.

Because the human brain costs so much more in energetic terms than the equivalent average mammalian brain, one might expect the human BMR [basal metabolic rate] to be correspondingly elevated.  However, there is no significant correlation between relative basal metabolic rate and relative brain size in humans and other encephalized animals.

Where does the energy come from to fuel the encephalized brain?

The authors postulated a solution.

One possible answer to the cost question is that the increased energetic demands of a larger brain are compensated for by a reduction in the mass-specific metabolic rates of other tissues.

In other words, if one organ – the brain, for example – is chewing up a lot of energy and contributing a disproportionate amount of the basal metabolic rate for the animal as a whole, then maybe another organ or group of organs are consuming less energy to compensate.  The heart, the kidneys, the liver, the skeletal muscles, the GI tract – all consume energy and contribute to metabolic rate.  Maybe one of these organs became smaller as the brain became larger over time.

We can hone our analysis a little finer if we begin to look at an energy-balance equation, but an energy-balance equation of a different kind.  I have written a number of times in this blog about the energy-balance equation that applies to weight loss: change in weight equals energy in minus energy out.  That is not the equation we’ll be talking about here.  The other energy-balance equation says that the total metabolic rate is the sum of all the metabolic rates of the various organs and tissues in the body.  If you add the metabolic rates of the kidneys, the heart, the brain, the muscles, the digestive tract and so on together, you will get the total metabolic rate of the body, which makes sense because it is the sum of the parts.

Total BMR = brain BMR + heart BMR + kidney BMR + GI tract BMR + liver BMR + the remainder of the body’s tissues.

The authors of the ETH set out to look at the metabolic rates of the various organs.  By a diligent search of the literature, they found that along with the brain, the the heart, the kidneys, the liver and the gastro-intestinal tract account for the vast majority of the total BMR.  They dubbed these organs as ‘expensive tissues’ because they consume a large amount of energy as compared to their size.  (Surprisingly, muscle mass doesn’t contribute all that much to the total metabolic rate (skin and bone contribute even less), which gives the lie to that old notion — that I, myself, have fallen prey to — that replacing fat with muscle increases metabolism significantly.)

Aiello and Wheeler reasoned that if the total metabolic rate stayed the same while the energy-expensive brain grew over time some other expensive tissue had to get smaller.  There could be no other solution.

But which of the expensive tissues got smaller?

Aiello and Wheeler examined the data on the metabolic rates and sizes of the various expensive tissues and learned that for a 65 kg primate, the heart, the kidneys, and the liver were approximately the same size as those of a 65 kg (143 lb) human.  The greater metabolic rate of the large human brain was compensated for by a GI tract significantly decreased in size.  It turns out that the GI tract of a 65 kg human is just a little over half the size of the GI tract of a similar sized primate.

The combined mass of the metabolically expensive tissues for the reference adult human is remarkably close to that expected for the average 65-kg primate, but the contributions of individual organs to this total are very different from the expected ones.  Although the human heart and kidneys are both close to the size expected for a 65-kg primate, the mass of the splanchnic organs (the abdominal organs) is approximately 900 g less that expected.  Almost all of this shortfall is due to a reduction in the gastro-intestinal tract, the total mass of which is only 60% of that expected for a similar-sized primate.  Therefore, the increase in mass of the human brain appears to be balanced by a almost identical reduction in size of the gastro-intestinal tract.

Below is a graphic from the ETH showing the sizes of the different organs as based on predictions from a 65-kg primate and the observed size in humans.

So we know that as humans evolved larger brains they simultaneously co-evolved smaller guts in order to maintain a set BMR.  And this is where the story gets interesting. Why?  Because

the logical conclusion is that no matter what is selecting for brain-size increase, one would expect a corresponding selection for reduction in the relative size of the gut.

Some researchers believe that increasingly complex activities drove the brain to enlarge.  As the authors of the ETH summarized it:

The relationship between relative brain size and diet is often mentioned in the literature on primate encephalization and is generally explained in terms of the different degrees of intelligence needed to exploit various food resources.  For example, [some] have argued that a relatively large brain and neocortical size correlates with omnivorous feeding in primates , which requires relatively complicated strategies for extracting high-quality foodstuffs.  Alternatively, [others] have suggested that frugivores have relatively large brain sizes because they have relatively larger home ranges than folivores, necessitating a more sophisticated mental map for location and exploitation of the food resources.

But it doesn’t matter whether our brains got big because our predecessors were socialized, developed complex foraging strategies, lived in and had to deal with groups or were skilled hunters, in order to obey Kleiber’s law, something had to force our guts to get smaller at the same time.  What could that be?

According to Aiello and Wheeler, it is increased diet quality that allowed the gut to get smaller while still absorbing the necessary nutrients to fuel the metabolism.  As they put it

The results presented here [in the ETH] suggest that the relationship between relative brain size and diet is primarily a relationship between relative brain size and relative gut size, the latter being determined by dietary quality.  This would imply that a high-quality diet is necessary for this encephalization, no matter what may be selecting for that encephalization.  A high-quality diet relaxes the metabolic constraints on encephalization by permitting a relatively smaller gut, thereby reducing the considerable metabolic cost of this tissue.

What the authors are saying is that it doesn’t matter how much more brain power was required, the brain couldn’t enlarge without something else giving.  What obviously gave was the size of the GI tract, and the only way a smaller GI tract could provide the fuel for the body was to have a higher-quality diet. How did the our most ancient relatives the early hominids increase the quality of their diets?

A considerable problem for the early hominids would have been to provide themselves, as large-bodied species, with sufficient quantities of high-quality food to permit the necessary reduction of the gut.  The obvious solution would have been to include increasingly large amounts of animal-derived food in the diet.

Increasing the amount of easily-digested food of animal origin allowed us to shrink our guts while expanding our brains.  Had we remained on a diet high in vegetation, we would no doubt not have been able to expand our brains irrespective of how much more thinking those brains would have needed to do.  It just wouldn’t have been possible to do so without violating Kleiber’s law.

Take the gorilla, for example, almost pure vegetarians that spend their entire ‘working’ day foraging and eating, which they have to do to get enough calories to maintain their enormous bulk.  They have large guts and pay for it by having small brains.  Even smaller than that of our most primitive ancestors, the australophthecines.

Gorilla has one of the lowest levels of encephalization of any haplorhine primate, and the much higher level of encephalization of all the australopithecines suggests a diet of significantly higher quality than that of this genus.

Which makes sense when you consider that carbon 13 isotope analysis has shown that Australopithecus africanus (the species that came right after Lucy) consumed meat.  As you go up the lineage from Australopithecus and through Homo, you find that more and more meat was consumed the higher up the tree you go.

It’s easy to see that, as compared to humans, chimps and gorillas have large, protuberant bellies, which supports the fact that they have larger GI tracts, but what about our ancient ancestors.  All we have to go on are skeletal remains, which show nicely that their heads (and brains) were much smaller than ours, but what about their guts?  How do we really know their guts were larger?  According to Kleiber, they would have to be, but how to we really know they were?

The large gut of the living pongids gives their bodies a somewhat pot-bellied appearance, lacking a discernible waist.  This is because the rounded profile of the abdomen is continuous with that of the lower portion of the rib cage, which is shaped like an inverted funnel, and also because the lumbar region is relatively short (three to four lumber vertebrae).

The drawing below from the ETH shows the inverted-funnel shape of the ribcage of the chimpanzee on the left.  You can mentally draw the lines downward from these ribs and envision the pot-bellied look of the abdomen that these primates evidence.  Looking at the image on the right, you can see that Australopithecus afarensis (Lucy’s species) has the same inverted-funnel shaped rib cage, indicating a large belly and a low-quality diet.

The drawing in the middle is of a modern human.  If you extrapolate the lines down from the human rib cage, you can see that they lead to a more narrow waist.  Makes you think more of a lean, rangy wolf or other slim-waisted carnivore, whereas the other two don’t.

The authors conclude:

If an encephalized animal does not have a correspondingly elevated BMR [which according to Kleiber, it can’t], its energy budget must be balanced in some other way.  The expensive-tissue hypothesis suggested here is that this balance can be achieved by a reduction in size of one of the other metabolically expensive organs in the body (liver, kidney, heart of gut).  We argue that this can best be done by the adoption of a high-quality diet, which permits a relatively small gut and liberates a significant component of BMR for the encephalized brain.  No matter what was selecting for encephalization, a relatively large brain could not be achieved without a correspondingly [sic] increase in dietary quality unless the metabolic rate was correspondingly increased.

At a more general level, this exercise has demonstrated other important points.  First, diet can be inferred from aspects of anatomy other than teeth and jaws.  For example, an indication of the relative size of the gastro-intestinal tract and consequently the digestibility of the food stuffs being consumed is provided by the morphology of the rib cage and pelvis.  Second, any dietary inference for the hominids must be consistent with all lines of evidence.  Third, the evolution of any organ of the body cannot be profitably studied in isolation.  Other approaches to understand the costs of encephalization have generally failed because they have tended to look at the brain in isolation from other tissues.  The expensive-tissue hypothesis profitably emphasizes the essential interrelationship between the brain, BMR, and other metabolically expensive body organs.

I hope you are now armed with enough knowledge to be able to see through these articles and/or charts that are all too common showing how the GI tract of humans is closer to that of a gorilla than it is to that of a cat or some other carnivore.  It seems to me that Aiello and Wheeler have pretty thoroughly demolished the notion that humans are actually designed by the forces of natural selection to be vegetarians.  Based on the data and the argument they present, it is actually the opposite:  we evolved to be meat eaters.

It was our gradual drift toward the much higher quality diet provided by food from animal sources that allowed us to develop the large brains we have.  It was hunting and meat eating that reduced our GI tracts and freed up our brains to grow.  As I wrote at the start of this post, the evidence indicates that we didn’t evolve to eat meat – we evolved because we ate meat.

Lierre Keith had it right in The Vegetarian Myth:

The wild herds of aurochs and horses invented us out of their bodies, their nutrient-dense tissues gestating the human brain.

If we evolved because we ate meat, why would we want to stop now?

Note: I found the full text of this article available on Scribd.  If it gets taken down, let me know, and I’ll put it up here.  I’m just trying to save space on my server.

Painting at top: Monkey Before Skeleton by Gabriel Cornelius von Max

But I have just recently been disabused of that notion.

My friend Tim Ferriss put up an excerpt of our new book The 6-Week Cure on his site a few days ago and asked me if I would mind answering a few of the commenters.  I told him I wouldn’t mind at all, but I didn’t realize what I was getting myself into.

Tim’s blog isn’t really a nutritional blog – it’s a lifestyle design blog (said term invented by Tim himself).  There is a little nutrition thrown in here and there, but mainly the blog is focused in other directions.  As a consequence, it attracts mainly youngish readers who enjoy following Tim’s adventures and want to learn how to model their lifestyles after his.  My blog is specifically directed to folks more interested in nutrition who are willing to put up with my digressions into other areas from time to time, so I expect them to be more nutritionally aware.

I wasn’t prepared for what I got in the comments on Tim’s post.  Surprisingly, there were a fair number of commenters – maybe even a majority – who would feel right at home on my blog.  But there were also a fair number who made me realize that nutritional sophistication is far from a universal phenomenon.  You can take a trip over to the comments section of his blog to see what I mean.  I pretty much answered only those who I thought were totally off track, so you’ll be able to read my comments, then track back to the comment I was responding to and see what I mean.

The experience made me realize just how much of a void there is in good info out there explaining why humans really are meat eaters at heart, so I’ve decided to do a couple of posts on the subject to be able to refer to in the future when this issue arises.  While I was mulling this idea over, I received a link to a piece of sheer idiocy that really pushed me over the edge.  It made me realize that if this kind of stuff is out there circulating, it’s no wonder these people have such bizarre notions of what constitutes a rational diet.

I’m going to start off this first part by examining some of this nonsense, and I’ll finish off in the second part by going through one of the classic papers of all time showing why we humans aren’t just meat eaters, but we are humans because we eat meat.

The link I had sent by a friend of mine is one I’ve seen referred to on a couple of other low-carb or Paleo sites.  I didn’t give it much thought until the Tim Ferriss blog experience (which, BTW, is still going on.  I just got binged on my email that Tim approved another 15 or so comments that I need to take a look at, so keep checking his blog) made me realize that there were really people out their buying into this nonsense.

The piece from AlterNet starts out with a big, bold headline:

Eating Meat Is Not Natural

No equivocating there.  A categorical statement if I’ve ever seen one.  Let’s see how the author of the piece – Kathy Freston – backs it up.  She starts out with a short introductory paragraph that ends with another categorical statement.  I’ve noticed that these folks love to write these things with such authority.  Same with the people on Tim’s blog.  There is no doubt in their minds that they’re correct.  But they are operating in an informational void.

Which brings to mind a great quote from Lierre Kieth’s book:

I was on the side of righteousness, and like any fundamentalist, I could only stay there by avoiding information.

Here is the intro paragraph to the AlterNet piece:

Going through the reader feedback on some of my recent articles, I noticed the frequently stated notion that eating meat was an essential step in human evolution. While this notion may comfort the meat industry, it’s simply not true, scientifically. [My italics]

No hesitance there.  “It’s simply not true, scientifically.”  Not even a smidgen of doubt.

How does our author prove it’s not true?  By referring to the writings of people who present themselves as scientists but who are ideological vegetarians.

Dr. T. Colin Campbell, professor emeritus at Cornell University and author of The China Study (please check out the link), explains that in fact, we only recently (historically speaking) began eating meat, and that the inclusion of meat in our diet came well after we became who we are today. He explains that “the birth of agriculture only started about 10,000 years ago at a time when it became considerably more convenient to herd animals. This is not nearly as long as the time [that] fashioned our basic biochemical functionality (at least tens of millions of years) and which functionality depends on the nutrient composition of plant-based foods.”

Ah, our old friend Dr. T. Colin Campbell and the China study.  Many commenters on Tim’s blog referenced this study as if were gospel.  Before we get into The China Study, I’ve got a disclosure to make.  I’ve never read the thing.  So how can I talk about it intelligently?  Because I have appeared on the podium with Dr. Campbell.  A few years ago we both spoke at a symposium somewhere (I can’t even remember where now), and his talk preceded mine.  As I sat on the stage, I listened intently and made notes as I watched his slides.  What I realized right off the bat is that his whole shtick is nothing but an epidemiologic or observational study, which, as I’ve written about in these pages  before, proves no causality and serves only to derive hypotheses.  He spent his entire presentation trying to prove his thesis with studies that can’t he used to prove diddly.  Since I spent an hour listening, watching and then rebutting, I figure I’ve earned a pass from reading the book.

If you want to read more on The China Study, I suggest you take a look at two sources.  First, read Chris Masterjohn’s review, then you can read Dr. Campbell’s rebuttal, then Chris’s response to that.  And you can read my good friend Anthony Colpo’s review of the book.  The China Study is a pretty sorry piece of work and, since it is an observational study (the results of which are misrepresented in the pop science book available), it doesn’t prove squat.  I certainly wouldn’t rush out and become a vegetarian because of it.  Yet if you read some of the comments on Amazon, you would think this book is the Second Coming.  These poor people who have been so gulled simply don’t realize how worthless such studies are.

In the quote above, Dr. Campbell is obviously unaware that the birth of agriculture involved primarily the turn from a hunting/gathering subsistence to the growing of grain.  The agricultural revolution wasn’t a change from a herbivore existence to the herding of animals for food.  This kind of clap trap shows just how misguided these kind of folks are and how they twist the historical facts to suit their purposes.

The next ‘authority’ trotted out by our author is none other than Dr. Neal Barnard, the president of the inappropriately named Physician’s Committee for Responsible Medicine and himself a vegetarian.

That jibes with what Physicians Committee for Responsible Medicine President Dr. Neal Barnard says in his book, The Power of Your Plate, in which he explains that “early humans had diets very much like other great apes, which is to say a largely plant-based diet, drawing on foods we can pick with our hands. Research suggests that meat-eating probably began by scavenging — eating the leftovers that carnivores had left behind. However, our bodies have never adapted to it. To this day, meat-eaters have a higher incidence of heart disease, cancer, diabetes, and other problems.”

This is the Dr. Barnhard of the much-ballyhooed (by him, at least) ‘study’ of the ill effects of low-carb diets that I rebutted a few years back.

He is correct in saying that the earliest of men probably begin to eat meat by scavenging.  The paleontological record seems to bear that out.  But the line about our bodies never adapting to it and the statement that meat-eaters have higher incidences of all the diseases mentioned is pure malarky.  If Dr. Barnhard were asked to come up with references for these statements, all he could possible produce would be a few observational studies, which, as we all know, don’t prove anything.  And for each one he could come up with, I could come up with just as many showing the opposite.

Now we get to the big gun: Richard Leakey.

There is no more authoritative source on anthropological issues than paleontologist Dr. Richard Leakey, who explains what anyone who has taken an introductory physiology course might have discerned intuitively — that humans are herbivores. Leakey notes that “[y]ou can’t tear flesh by hand, you can’t tear hide by hand … We wouldn’t have been able to deal with food source that required those large canines” (although we have teeth that are called “canines,” they bear little resemblance to the canines of carnivores).

Hmmm.  I wonder if Leakey has ever seen the canines of a gorilla?  They certainly have the appearance of the canines of a carnivore yet gorillas are pure vegetarians.  But let’s go on.

In fact, our hands are perfect for grabbing and picking fruits and vegetables. Similarly, like the intestines of other herbivores, ours are very long (carnivores have short intestines so they can quickly get rid of all that rotting flesh they eat).  We don’t have sharp claws to seize and hold down prey.  And most of us (hopefully) lack the instinct that would drive us to chase and then kill animals and devour their raw carcasses. Dr. Milton Mills builds on these points and offers dozens more in his essay, “A Comparative Anatomy of Eating.”

All this anatomical stuff is pure gibberish, yet many people not skilled in the art of critical thinking buy into it.  In part II of this post, I’ll address many of these anatomical issues, so we’ll leave it until then.  If you’re bored, you might want to take a look at the Comparative Anatomy of Eating, which is a not-very-successful attempt to push a square peg into a round hole.  Dr. Milton really has to stretch to get the anatomy to fit with his notions of what it is designed for.  I’ve seen so many variations on this theme – people showing minor anatomical differences to prove that humans are really herbivores – that I’ve lost count.

The author now turns to her last expert, a big time, mainstream doctor.

The point is this: Thousands of years ago when we were hunter-gatherers, we may have needed a bit of meat in our diets in times of scarcity, but we don’t need it now.  Says Dr. William C. Roberts, editor of the American Journal of Cardiology, “Although we think we are, and we act as if we are, human beings are not natural carnivores.  When we kill animals to eat them, they end up killing us, because their flesh, which contains cholesterol and saturated fat, was never intended for human beings, who are natural herbivores.”

This guy really goes off the rails.  He tells us that “when we kill animals to eat them, they end up killing us,…”  A strong statement that he has absolutely nothing but his own opinion to back it up with.  Then he really takes a leap.  These animals we kill to eat do us in “because their flesh, which contains cholesterol and saturated fat, was never intended for human beings, who are natural herbivores.”  Oh, really.  That cholesterol will do us in, eh?  Why is it that we have cholesterol ourselves and plants don’t?  Why is every cell in our bodies capable of making cholesterol?  Because we don’t need it?  The depth of his dumbth is unfathomable.  Realizing that this guy is the editor of a major cardiology journal lets you know really quickly why such journals publish such biased articles.

Our author goes on.

Sure, most of us are “behavioral omnivores” — that is, we eat meat, so that defines us as omnivorous. But our evolution and physiology are herbivorous, and ample science proves that when we choose to eat meat, that causes problems, from decreased energy and a need for more sleep up to increased risk for obesity, diabetes, heart disease, and cancer.

Here again with the meat causes obesity, diabetes, heart disease and cancer.  Instead of the “ample science” she claims, there is no proof whatsoever.  She uses an interesting expression: she describes us humans as “behavioral omnivores,” which I think is a good definition, but she’s using it incorrectly.  She means that we are really herbivores, but we’ve learned to become omnivores, therefore we are behavioral omnivores, not real omnivores.  I agree with her, but with a twist.  I think we are designed as carnivores and have adapted to an omnivore existence, so we are behavioral omnivores, just not the way she thinks we are.  Gorillas are behavioral vegetarians.  They have the GI tracts from teeth to the other end of carnivores – and they do fine being fed meat in zoos – but they culturally are vegetarians or behavioral vegetarians.

Old habits die hard, and it’s convenient for people who like to eat meat to think that there is evidence to support their belief that eating meat is “natural” or the cause of our evolution. For many years, I too, clung to the idea that meat and dairy were good for me; I realize now that I was probably comforted to have justification for my continued attachment to the traditions I grew up with.

But in fact top nutritional and anthropological scientists from the most reputable institutions imaginable say categorically that humans are natural herbivores, and that we will be healthier today if we stick with our herbivorous roots. It may be inconvenient, but it alas, it is the truth.

She ends by summarizing all the twaddle she presented earlier.  And she relies on what others say to ‘prove’ her points – all the top scientists at all the most reputable institutions – which is a dead give away that she hasn’t gone to any original sources herself and is simply relying on hearsay.  But, hey, she’s a journalist, not a scientist, so she’s got to rely on the scientists to tell her what’s going on, right?  To a point, but she should also check with some other “top scientists” from other “reputable institutions” to perhaps provide counter opinions.

It almost defies belief that people can be so gullible as to put any credence whatsoever in an article such as this one, yet, after dealing with Tim’s blog, it’s apparent that many do.

One journalist who doesn’t, however, is my friend Amy Alkon, better known as The Advice Goddess who writes a syndicated column that I never miss.  In her latest, published in the Orange County Register, she gives advice to a vegan who has come a cropper in a burgeoning email romance with a non-vegetarian.  As you read the request for advice from the vegan, you can see her innate sense of moral authority start to bleed through.  Amy’s advice is priceless. (It was Amy, in fact, who emailed me the link (after some zealot had sent it to her) to the article above that I’ve just spent three pages dissecting.)

While you’re at it, read her advice to the next seeker after the vegan.  My favorite line:

People say the best things in life – love, friendship, moonlight – are free, but so are the worst things: lymphoma, a really big overbite, and road kill.

How true, how true.

The next post is going to be free, and I hope it will fall into the good kind of free category.  We’ll go over a famous paper from the anthropological literature making a virtually watertight case that it was eating meat that made us human.