The big flaw of this sort of argument for low carb diets is all of the assumptions that aren't in accordance with evolutionary theory. Supposing that we were mostly hunters for a long time, that probably means that we can consume meat healthfully. But does it mean that we lost our ability to run on carbohydrates healthfully? Somewhere in our past we ate a lot of fruit and tubers, and then became more meat-centric. So these genes for living off of carbs would still be in the genome. The assumption that we ever stopped expressing them is untenable, and furthermore, even if we did lose them, old genes that haven't predominated in a while can easily be selected for again in a short time with the right kind of selection pressure: the new carb-centric agricultural diet. I'm not saying that this did happen, but I don't see how people could say that it didn't either.

The paleo principle makes sense in one aspect that I can identify so far. If there has been something introduced into the diet that we have never ever seen in our evolutionary history, like trans fats, then we can be very suspicious that it might be bad for us, particularly if it has an obvious toxic feature, like grains. We can't say that it is, but we can hypothesize it and be extra critical of this new food. No macronutrient is evolutionarily novel.

I'm pretty sure that we're not biologically vegetarians. But how close to vegetarians can we get without hazard to health?

It's kind of hard to see how the post says much of anything. I think most of us already accept that early humans got their protein from animals, not tofu and wild rice cakes, which is exactly what the isotope studies tell us. Unfortunately, they don't tell us how much protein they ate nor what proportion of the diet it was, which at least Eades admits. In order to figure out the rest of the diet (the fat and carbs), we are stuck with analyzing animal/fish bones and looking at relevant climate and botanical data, which are methods that are pretty limited in accuracy, but at least can give us an idea of what was available. I think this is where Eades (and others) show their limits, but part of the fault is that there isn't much collaboration between the archeologists that specialize in animal remains, those that specialize in hominid bones, and paleobotanists.

I disagree for a couple of reasons. First, we can be pretty certain what our European ancestors didn’t eat. They didn’t eat dwarf wheat, Red Delicious apples, bananas, Bartlett pears or any other hybridized or tropical fruits commonly available today. As far as we know, there were no Paleo Luther Burbanks grafting and hybridizing plants to make them bigger and sweeter. Our predecessors would have eaten whatever plant foods were at hand, which is pretty much what you still find if you go out in the woods today. They would have had to battle the birds and other wildlife to get to these fruits, and would have had them available only seasonally.

First of all, this is Eurocentric and while I am quite interested in the idea that northerly groups of people might have some special metabolic adaptations to their diet, so far it's just conjecture. Second, it underemphasizes the immense diversity of plants available, most of which a modern American wouldn't think to eat and many of which are available year round, even in cold climates, and some of which humans don't compete with animals for because they require grinding/cooking/leaching or other advanced processing methods to render edible.

And so what if they didn't eat apples? They didn't eat beef or pork either. It's the same argument Cordain uses when he says to avoid high intakes of fat.

So TLDR: the archeological evidence shows that early hominids ate animal protein + some unknown combination of animal/plant fats and plant carbohydrates.

He's right, for what the post is saying. Though, as others noted, it is Eurocentric. From my research and N=1 testing on myself and my wife (I'm of European decent, she is African), I am very sensitive to carbs, she is not. I use starches to gain weight when I want to get bigger, and she can eat them much more than I (and in our blood sugar testing, she is much less effected than I am as well).

However, that being said, it is VERY likely from all the research we've done that an optimal diet includes starches, just not that many. However, if one is looking to get very, very lean...no matter the person or ethnicity, no starches should be used. This is just common sense coupled with science.

So, bottom line, know your goals. If you are going for optimal nutrition and don't care what you look like, include starches. If you are going for lean or low body fat, no starches (except for you carb refeed days...I have one every 14 days as I try to get pretty shredded).

I am 21 years old. For the majority of my life I was a virgin. During these years I was certainly my happiest, most carefree, and healthiest.

Recently, in the last 2 years, I have developed a couple non-trivial medical problems (not related to STDs). Strange, is it not, that this aligns closely with the end of my virginity.

For the vast majority of my life I was adapted to not having sex. My n=1 experience says sex causes medical problems. Prompted by this revelation, I decided to dig deeper.

You see, my friends, I discovered that sex is a postpubescent agent of disease

Consider!, if you will, the majority of our evolution. Originally, we arose erratically as reproducing molecules, eventually coalescing into prokaryotic cells. Finally we developed nuclei, engulfed some of our ancestors to develop mitochondria, and lastly we developed sexual reproduction. For the majority of our evolution we did not have sexual reproduction!

Some more points for the nonbelievers!

1. I also weighed significantly less when I was a virgin (if you average across all years). The conclusion therefore is that sex lowers leptin quantum sensiquackery... err sensitivity. Or perhaps sex makes me insulin resistant? (Never mind the fact that insulin resistance is a pathology that develops to oppose gaining fat). Furthermore, let me point out that my sex is short and hard, HIIT if you will, no chronic cardio for me! This should raise insulin sensitivity and provide a hyooge HGH pulse to make me shed the fat. Not so, as sex is evil.

2. Sexual reproduction leads to every other thing hated by a majority of paleos. Gluten? Comes from wheat, and you had better believe wheat has sex. Dairy? Meant to help a newborn calf, conceived via the SEX. Nuts? Direct sexual imagery.

3. The reason we have mitochondrial leptin dysfunctionosmolarity is because mitochondria came form prokaryotes, and were not adapted to having sex!!!

Try my sex reset and I gaurantee you will lose weight. We need to recycle your diurnal sexual rhythmobalance.

First, you cannot have sex (with humans). Instead, you must spend time pleasuring your meals instead of eating. After mating with a few steaks instead of eating them, I gaurantee you that you'll lose weight.

Second, you must avoid all insulin spikes/pulses, as a pulse is clearly a phallic symbol and therefore sexual.

Stay tuned for an explanation of why this works.

Conciliator MD, PhD, Neuro-macgyver.

I find the speculation about what our ancestors ate fascinating. But since the planet is very diverse in terrain and climate, I don't think we should be surprised that humans have adapted in diverse ways.

I'm totally convinced that Dr Eades speaks correctly about me, because my genes are a mixture of at least 3 far-northern countries. So yes, I thrive on meat and like greens and fruit (even if my ancestors only had it in season) and I like rutabaga better than sweet potato. To the extent that I know, all my blood relatives appear to prefer a similar diet.

But the arguments left me confused--where's the data from African, Middle Eastern and Asian bones? Since those places are both warmer and were more heavily populated even in the paleolithic, we can't assume isotopes will tell the same story. After all, maybe the meat-eaters were the ones who left and the carb eaters were the ones who stayed--with the "half & half" folks well represented in many areas as well?

I appreciate the explanation Eades provided about using isotopes to distinguish between terrestrial and marine sources of animal food. I'd never heard that before.

From Eades' post, emphasis mine:

…the European Neanderthal diet indicates that although physiologically they were presumably omnivores, they behaved as carnivores, with animal protein being the main source of dietary protein.

...The bulk of the stable isotope studies show both Neanderthals and ancient humans were, at their robust cores, meat eaters to the max. What the stable isotope studies don’t show, is how much carbohydrate these folks ate along with their meat. (Actually some stable isotope studies do show what kind of carbs in the sense that they can differentiate between grains and non-grains, but since there were no grains in Paleo times, that isn’t a concern.) But since we do know that wolves and foxes are predators that consume mainly food of animal origin, and we know that early humans have an even more carnivorous stable isotope footprint, it seems unlikely that these humans would have consumed many calories from non-animal sources. Remember, natural sources of protein are virtually always associated with fat (copious amounts of fat if the protein is from large game and the entire carcass is consumed), so it’s doubtful there would be either the capacity or the necessity for complementing the basic diet of fat and protein with much carbohydrate. But, nonetheless, even if our ancient ancestors did eat some carbs they could scrounge while in season, the stable isotope evidence clearly demonstrates they were not vegetarians.

The thing about hunting something to extinction, is that it's no longer a food source. Even eating modern marbled meats and poultry, Eades still suggests tucking butter under the skin of chicken thighs. Those Mangalista piggies he's so fond of were bred and fed to be fat. If these paleo humans ate very little starch, can we at least assume that most of their prey also ate very little as well? That they were "grass fed", and there wasn't a whole lot of fat on these animals, even if Grok ate all the guts and such to boot.

It's odd how he mentions Cordain, he is referenced in the classic Eaton papers (The ancestral human diet: what was it and should it be a paradigm for contemporary nutrition? and Paleolithic nutrition revisited: A twelve-year retrospective on its nature and implications and so often cited by low carbers. The Eaton works do not seem to indicate a "high fat" diet. Paleo macro ratios are closer to Zone than VLCHF in those papers. The table below is from the second paper:

I wonder how these sources all settle out. Did Cordain have any sort of a revelation in the cafe with Eades?

I just posted this link over in the comments about Eskimos whose diets we CAN know with certainty: http://www.jbc.org/content/80/2/461.full.pdf “According to their data the average daily food partition is about 280 gm. of protein, 135 gm. of fat, and 54 gm. of carbohydrate of which the bulk is derived from the glycogen of the meat eaten.”

Anyone else notice that the 6 Week Cure has done a disappearing act on his blog? LOL!

I don't think there is sufficient evidence to compel people who have committed themselves body and soul to a contrary vision. All the arguments I hear for significantly increasing carbs seem to be rooted in the same philosophy as the conventional wisdom that brought us here over the last few decades. I can only really think that people who are heading that way never really understood paleo as an idea, and don't know why they insist on describing their lifestyle as paleo. Not that it matters either way, but it does get quite confusing.

The focus on what people ate and when is not terribly helpful until we have a lot more data points. Knowing what a tribe ate is an anecdote. Humans evolved over hundreds of thousands of years across diverse geographies and climates. The food supply would be frequently changing, and local adaptations that thrived could be less optimal, yet still persist in the genome, even as food scarcity drove diets in a different direction. That means we may be adapted to eat more foods than just what was available to Grok. Maybe not, but my point is that based on what we do know, we can't conclude that eating a certain diet is backed up by ancestral record.

Eades Carnivory Analysis Spreadsheet (Google Docs)

A point that bears repeating is that this provides data around the source of protein, not the percent of protein -- or any other macronutrient -- in the diet. That said, I put together a spreadsheet to play around with it all.

I took the bar charts from the first slide from Eades' post and using an image editor, figured out their heights, and so figured their delta-15N. Then, I combined plant protein, bison protein, and arctic fox protein in a hypothetical fashion to look at the range of protein sources. We end up with a table like this:

      Percent of dietary protein
Scenario  Plant  Bison  Arctic Fox
   1        0%    87%      13%
   2        5%    76%      19%
   3       10%    65%      25%
   4       15%    54%      31%
   5       20%    43%      37%
   6       25%    32%      43%
   7       30%    21%      49%
   8       35%    10%      55%

So in scenario 1, if one consumes no plant protein, 87% of their protein from bison, and 13% of their protein from arctic fox, then one would end up with a delta-15N of 10.4. All 8 of those scenarios result in a delta-15N for the consumer of 10.4.

Then if you plug in some assumptions for macronutrient composition by food source, you can come up with estimates for a range of macronutrient consumption. With my assumptions, I end up with pretty wonky data. I end up with this table for the above 8 scenarios:

      Percent of calories
Scenario  Carb  Protein  Fat
   1        1%    79%    20%
   2        5%    76%    19%
   3       10%    72%    18%
   4       14%    69%    17%
   5       19%    65%    16%
   6       23%    62%    15%
   7       28%    58%    14%
   8       32%    55%    13%

In all cases, the protein looks awful high to me.

So, I'm sure I'm wrong about my assumptions, or something. But that's why I've published my spreadsheet on Google Docs. Please feel free to take it and mangle it how you wish and put your results out there if you'd like.

https://docs.google.com/spreadsheet/ccc?key=0Akqazlc7cJytdF9FN3IzRzE2ZG1OZ2J2aGo5X0JMTFE

Ed

It seems like the evidence he presents best supports the (fairly uncontroversial IMO) idea that humans are meat eaters rather than vegetarians (thus, the title). Even though I agree that human evolution was characterized by a lot of hunting and fishing, I don't think this necessarily pushed carbohydrate containing foods out of our diet by proxy. He does little to address evidence supporting starch consumption (e.g. human salivary amylase level compared to various primates) and simply presents ideas about how fruit is seasonal and postulates about the impact of its unavailability to Europeans.

Interesting read nonetheless.