> Our ancestors ate a Paleo diet. It had carbs.

Yeah, it had carbs. Just not nearly as many as this anthropologist wants to believe. Studying modern "hunter gatherer" populations is not a particularly scientific way to judge what it was that our human ancestors and their related species were actually eating several thousands or millions of years ago. Doing so might instigate some interesting questions, but there's clear and obvious limitations to studying a scant few tribes that can be considered hunter-gatherer in an era where it's nearly impossible not to have some form of contact with the "civilized" world.

> I would say the same is true of the predominant Paleo diets today — most are very meat-heavy and low-carb, downplaying things like starchy vegetables and fruits that would only have been seasonally available before agriculture.

That is if they even would have been available at all. Fruits and starchy vegetables in their current form are almost unrecognizable to their evolutionary counterparts millions, thousands, or even hundreds of years ago in many cases. The starchy tubers that early modern humans sometimes ate were fibrous, not particularly starchy in contrast to agricultured sources of starch like pretty much any variety of potato. Fruits are no different. The vast, vast majority of fruits before agriculture were not abundant in fruit flesh; they had enough flesh such that it encouraged animals to consume and poop out the seeds (if that was the strategy of the particular plant). Plants did not have the same pressure they do now to produce highly fleshy fruit at a genetic level as they do now because the energy and substrate were not there.

> But our ancestors’ diets were really variable.

Depends on which ancestors and when. When you look at the 4 million years prior to the last 30k years, our diet was not particularly variable. This has been confirmed by stable carbon and nitrogen isotope testing of bone collagen found in human remains. Not dental calculus or tools or other things that are speculative. Humans ate mostly meat to the point where it was nearly exclusive.

> We evolved as hunter-gatherers, so you’re hunting and gathering whatever foods are around in your local environment.

We are hunter-scavengers, for the most part. Under most circumstances, the natural environment, in terms of plants, does not have enough available net energy to be a comparable strategy to hunting or raising animals that do. Unless you're fortunate enough to be around something like an acorn tree at the right time of year, your choice is to kill and immediately eat the flesh of an animal or to eat leaves and fibrous roots of plants of which there is comparatively very little nutrition or available energy. Harvesting, processing, and passing mostly indigestible plant material is not nearly as efficient or nutritious as killing and eating animals. Gathering was and still is a distantly second strategy that opportunistic humans use to extend their chances of survivability.

> Humans are strategic about what foods they go after, but they can target only the foods that are there. So there was a lot of variation in what hunter-gathers ate depending on location and time of year.

Depends on what "a lot" means. Plants fruit, animals migrate. Doesn't mean that the majority of environments early humans were living in were cornucopias of food worth eating.

> The other thing is that, partly due to that variability, but also partly due just to people’s preferences, there’s a lot of carbohydrate in most hunter-gatherer diets.

Depends on what you mean by carbohydrate. Assuming you're not lumping indigestible fiber into this, the premodern earth was not full of starch and sugar.

> Honey was probably important throughout history and prehistory.

Sure, when it was available and when you were willing to get stung. There was never enough honey at any point in prehistory to be a meaningful source of energy that humans were optimized to rely on. It was a supplemental and tasty form of supplemental energy if it could be obtained.

> A lot of these small-scale societies are also eating root vegetables like tubers, and those are very starch- and carb-heavy.

No, they were not particularly starch heavy at all, all things being relative. Heavy compared to what? Compared to the root vegetables available to us today, not even close.

> So the idea that ancient diets would be low-carbohydrate just doesn’t fit with any of the available evidence.

Complete nonsense. Humans ate carbohydrates, but available and digestible carbohydrates were mostly not available in abundance until humans figured out how to manipulate their own environment. On a scale of pure energy investment, gathering loses almost every time to modestly skilled hunting based on human nutritional needs.

> I think there are a couple of reasons for that. You have a kind of romanticizing of what hunting and gathering was like.

That's really what you're doing here. Using anecdoes about specific modern tribes eating honey is a form of romanticizing paleolithic and pre-paleolithic human existence, which for the most part was harsh and brutal.

> There is a sort of macho caveman view of the past that permeates a lot of what I read when I look at Paleo diet websites.

Maybe that's because later stone age humans were more macho than we are both in terms of testosterone level and overall phenotype. The longer that early human species adapted to eating meat and away from primarily fruit-eating, the more "masculinized" their phenotype. A reverse effect has been proposed for why modern humans of the last 30,000 years are somewhat less masculine-appearing than their recent hunter-gatherer predecessors.

One doesn't even need to be aware of the fossil record at all. Take any two twins, feed one only meat feed the other one mostly carbohydrates and guess which one will have higher androgen levels.

> There are also inherent biases in a lot of the available archaeological and ethnographic data. In the early 1900s, and even before, a lot of the ethnographic reports were written by men who focused on men’s work.

Anything that men do is sexist. We got it.

> We know that traditionally that’s going to focus more on hunting than on gathering because of the way a lot of these small-scale societies divide their work: Men hunt and women gather.

Yes. Male and female humans have differing phenotypes and tradeoffs that encourage them to organize themselves into different specialties. It really doesn't make sense in most cases for females, who only have so many eggs available at limited times to have a limited number of offspring, to go hunting or fight other tribes. Females who are pregnant and literally can't hunt can still gather and process food among other things. It doesn't necessarily have anything to do with tradition.

> On top of that, the available ethnographic data is heavily skewed toward very northern cultures, such as Arctic cultures — since the warm-weather cultures were the first ones to get pushed out by farmers — and they do tend to eat more meat.

There historically have been more large ruminant animals in the northern hemisphere. Southern environments have less land mass and

> But our ancestors’ diets were variable.

Yes, humans are opportunists.

> Populations that lived near the ocean and moving rivers ate a lot of fish and seafood.

In other words, when meat is available, it's the obvious choice and has a positive correlation with survival, far more so than if all that's around are plants with inferior nutritional value.

> There is also a bias toward hunting in the archaeological record. Stone tools and cut-marked bones — evidence of hunting — preserve very well. Wooden sticks and plant remains don’t.

Because stone tools surely would have no use at all for processing, cutting open, and eating plants? Surely early humans would have never used sharp and pointy rocks to process acorns, break open coconuts, dig up and cut out roots, and so forth. No way they did any such thing. They just took bites right out of plants and used wooden sticks for everything.

You're ignoring the stable isotope data that doesn't match your conception that prehistoric humans ate "a lot" of carbs.

> Your research has focused a lot on a group called the Hadza.

Exactly. One tribe.

> People have been working with the Hadza for decades now, so we have these long-term records, papers published from 30 or 40 years ago up through to today.

That hardly sounds like anything near a form of a controlled study of a genuine hunter gatherer society that supposedly reflects hunter gatherers in general thousands and millions of years ago. Like I said, such study can lead to a lot of interesting questions, but the answers are where the anthropology mostly ends and science begins.

> [A] lot of the work there kind of sparked this — is how important honey is. It can make up as much as a fifth of the group’s calories, on average. Honey is just sugar and water — pretty high-carb and definitely not part of most modern “Paleo” diets.

I'm sure that's a situation that would have applied to the vast majority of premodern human groups at any particular time. You don't even mention what species of bees are producing this honey. Were there bees around in the paleolithic era that were capable of producing the copious amounts of honey that modern western honey bees do?

> The birds have adapted to a world in which humans get a lot of honey. I think that’s really telling.

That's not telling of anything other than that a couple of intelligent species have learned to work to each other's shared advantage in this one particular circumstance.

> Recently, there’s been some really cool work looking at the little bit of plaque and calculus stuck to the teeth in fossilized hominids. If you look at that, you’ll find remains of plants and starches.

Sure, if you ignore all the other research on dental calculus that shows populations of humans ate exclusively meat. Even the groups of humans that were found with plant material in their calculus still usually weren't subsisting primarily on plants or "a lot of starch."

> There’s even some evidence of a primitive flourlike substance that’s made out of grains.

That doesn't mean it's optimal or reflective of what our human ancestors primarily developed to survive on for over 4 million years. Eating grains can have a survival benefit, but some evidence that some early humans ate some amount of grain doesn't necessarily confirm that this is a reason to introduce starch into one's diet as a modern human.

> That kind of thing is anathema to most Paleo diets, which say that you can’t eat grains because grains are a farmed food.

Maybe that's because paleolithic humans weren't eating shittons of grains and because grains have properties that are deleterious to the human body. I'm sure there were some paleolithic humans that ate clay when food was scarce. Does that mean we should be eating clay?

> And you can look at the human body and see how we’ve adapted relative to our ape relatives — what’s changed in us in terms of how we digest food.

Yes, you can, and I'm sure you'll interpret such information correctly.

> You can look at things like gut anatomy and tooth shape.

Yes, you can. Our gut anatomy, in several ways, reflects that of hypercarnivores. In some ways, it reflects carnivory more than animals like cats, which eat exclusively meat; our stomachs highly acidic and our cecum is next to nonexistent, hence we are far better suited to digest meat than to process cellulose.

Our tooth shape really doesn't mean what you think it means. The advantage of pointy teeth in most animals is that they are effective for hunting their prey. I don't recall ever hearing about humans chasing and killing animals with their teeth. Humans also don't seem to have a problem eating meat with their teeth.

> And if you look at that, again, the signal is kind of omnivorous. It isn’t particularly meat-heavy.

Total unadulterated nonsense. The only way you can come to this conclusion is if you deny the mountains of evidence that dwarf your view that early humans were eating a bunch of starch.

Just because humans can eat plants doesn't mean they're optimal. Most species, including rats, develop to specialize towards a particular food substrate. Giving either humans or rats a bunch of carbs is demonstrably not health promoting for either species, despite rats being even more opportunistic than humans, despite their penchant for eating garbage.

> I think this adds to the evidence that humans can be healthy on a wide range of diets.

They can be, yes. That doesn't mean someone is wrong for eating a "Paleo" diet, which you seem to have a motivation to deboonk. Some diets are more optimal than others.

> I hope it helps tamp down some of the yelling on both sides about how you have to have a plant-based diet or you have to have a meat-based diet, or you have to have another kind of diet.

No one "has" to eat anything they don't want to. What people want to do is eat a diet that they believe is most optimal for them.

> Humans evolved to be adaptable.

And other animals haven't? Plenty of animals are "adaptable", whatever that means. Cows will eat meat if you put it in front of them. That doesn't mean it's optimal for their health in either the short or long term. Does the fact that most other animals can consume a variety of things and survive suggest they are "adaptable"?

We might be more adaptable in the sense that we believe ourselves to have the most advanced minds on the planet, thus we ca make analytical decisions that other animals either can't or take extremely long amounts of time to do. This effectively explains the invention of agriculture and livestock. That much better represents our adaptability than whether we can consume carbohydrates.

> And people who are vegan, and eat no meat at all, can do really well, too.

They can, but often don't.

Vegan diets have some advantages over a standard modern diet, namely that it doesn't activate the Randle Cycle if their consumption of fats is scant. This is one reason why people who switch to a vegan diet can feel better; their blood sugar is better regulated despite primarily eating carbohydrate.

A potential disadvantage of vegan diets is that, despite the insistence of its most adamant adherents, it is nutritionally inferior to a diet that includes meat, thus more effort needs to be made to get enough essential nutrients, and this is often not done correctly. Same applies to protein specifically.

But that's really getting beside the issue. The point is it's theoretically possible to remain at stable health on most diets, but it doesn't follow that humans are better off eating a variety of foods when a few particular foods have clear advantages in terms of nutrition and historical availability.

> I think the one thing that they never have in a hunter-gatherer diet is the heavily processed foods that we are surrounded with.

In principle, I agree, though the "processed foods are bad" thing is a bit of a meme at this point. Take pretty much any non-standard diet and you'll probably find it involves fewer processed foods.

> You take out a lot of things like fiber

You don't need fiber, actually, at least when you're eating primarily meat.

> Processed foods seem to be a big driver of obesity.

Yes, though not so much that they lack fiber and more that they contain poisons and activate the Randle Cycle.