In the year 1995 anyone who got worked up about what cavemen ate 50,000 years ago was treated with derision and viewed as an oddity.

The importance of food choice didn’t really enter the public zeitgeist until 2005 or so, and if you were outspoken about it your curiosity about what our paleolithic friends munched on was probably grouped with other nerdy fetishes likes model trains and Star Wars memorabilia.

Of course times are very different now.  Three out of four adults are overweight or obese, and 40% suffer from some form of the metabolic syndrome.   The combination of a prolonged recession, three decades of muted agricultural productivity, and an increased reliance on corporations for calories have left the average Joe out of shape, medicated, and wondering just what the hell he’s exactly supposed to eat.

The past ten years have allowed us to witness many cookbooks to be published, gourmet restaurants to be opened, and popular brands of food to be established all in the name of making the ancestral diet more accessible.   Pinpointing the ancestral (“paleo”) diet has blossomed into a multi-billion dollar industry that shows no signs of slowing down.

Which begs the question:  After 10+ years of intense inspection how much do we know about what Grok ate?

By and large I think this question has been settled, thanks in large part to the steadfast work done by authors like Mark Sisson.  But there are still some important details about the true paleo diet that haven’t seeped their way into public discourse yet.

For sure Grok probably loved to hunt an animal every now and then, didn’t take anything out of a plastic wrapper, and ate carbs that had way more fiber and way less of a glycemic load than we do today.   That’s uncontroversial, and I think everyone can agree on that…..and we’re all healthier for it.

But even when I read high level paleo blogs I see a few important points that are overlooked.   These facts have varying levels of currency depending on who you talk to, but to me represent the most underappreciated aspects of the caveman diet.

1). The Ancestral Diet Included a Lot of Bugs

The transition from a nomadic to a sedentary lifestyle probably did a lot to enhance our ability to consume meat and diminish our propensity to consume insects.

A cultivated goat is readily available, free to milk, and no longer requires a large investment in resources and uncertainty in order to get calories from it.

However, under nomadic conditions when access to animal calories is seasonal and hard to predict, insects are an incredibly convenient source of animal nutrients.

They’re much easier to collect, are available year round, and incredibly nutritious to boot.

Westerners insulated from non-SAD ways of eating might be shocked to find out that 2 billion people eat insects on a regular basis.   This is especially true in tropical locales where insects are especially plentiful and available to eat.

Here’s a revealing graph from an FAO report on the possibility of future insect consumption.  It compares how frequently different animal products are eaten in tropical locales.   Move over chicken, step aside beef jerky,  caterpillars are the staple animal product in the Democratic Republic of Congo.

And insects certainly do a body good.  Here’s a comparison of the protein, calcium and iron content of various insects compared to beef:

Got crickets, anyone?

2).  The Ancestral Diet Was Largely Vegetarian

When we think of the ancestral diet the image that instinctively comes to mind is a muscular Grok dragging a woolly mammoth carcass back to his tribe for butchering and a caveman feast.

We certainly don’t think of him as spending most of his time clawing through the dirt to pull up a starchy weed or scrounging up some nuts.  But there’s good reason to believe that’s exactly what early man spent most of his time doing.

Archaeological techniques have progressed to the point that we can now examine tooth fossils and trace residues left on spears, flakes, and digging rocks to gain insight into what pre-historic people ate and what they used their tools for.

And it looks like a large portion of their time was spent trying to harvest and process various plant foods.  The tooth enamel of neanderthals and cro-magnon man from the best preserved excavation sites turn up a lot of starch granules that date back to 30,000 years.

Another paper that examined the trace oils and micro-fossils left on flakes and spears from an excavation site in Mozambique closely matched those of many ancient grains.

The majority of ethnographic studies suggest that most hunter-gatherers get the majority of their calories from carbohydrates.

So exactly how vegetarian were they?

That’s harder to say.

But one thing’s for certain:  they weren’t vegan.  The ethnographic atlas is a compilation of data collected on 1167 cultures, and it certainly appears that the consumption of flesh is a constant across most societies.  Perhaps hunter-gatherers don’t eat it as often as they’d like, or as much as we envision in our caveman fantasies, but the consumption of animal products (or at least the attempt to) never goes away, and is usually a prized item.

However, the exact meat/non-meat ratio is a much more difficult nut to crack.

On the high end you have researchers like RB Lee who’s extensive work with the !Kung bushmen suggested it was probably 65:35 in favor of plants to animals, and possibly as high as 80%.  On the other end you have Loren Cordain, who’s done a lot of research on paleolithic nutrition and has published papers suggesting the ratio is the exact opposite.  (See also here, a very useful overview of this topic).

The truth is that it’s impossible to tell and almost certainly varies from season to season and region to region.  In fact there’s good reason to believe that the diet of hunter gatherers today doesn’t even resemble the traditional paleolithic diet all that much thanks to changes in environment and our own genome since the dawn of agriculture.

3). The Ancestral Diet Wasn’t Raw

The notion that people were meant to eat a diet consisting of entirely raw foods is noxious and absurd.  The ability to manipulate fire and use heat to change the properties of food is one of the most distinctive traits of human culture and one of the biggest dividers between man and other animals.

The practice of cooking is also ancient.  At the earliest it probably started about 250,000 years ago, but there’s good evidence that suggests homo erectus began to manipulate fire up to 2 million years ago.  The presence of fire is why we can tolerate carbs that other animals can’t, why we have small teeth and small digestive tracts, and why humans have comparatively small differences between male and female stature compared to other primates.

You might even be able to say it’s the reason we colonized the world.

Yep, we’ve probably been cooking our food for a few million years.   The ability to cook is probably right up there with the use of language as one of the primary drivers of where we are as a species.  There’s no reason to think that having a 100% raw diet is optimal for human health.

In fact, it’s outright stupid.

4).  It Didn’t Contain Very Much Muscle Meat

If an Aboriginal saw what we did to a cow he’d probably shake his head in disgust.  When the butcher gets a cow he’s accustomed carving up its muscle tissue and discarding its less savory parts such as  organs and the blood without second thought.  But it looks like most of the non-agricultural world does the exact opposite.

It’s a uniquely western mindset to prize the muscle above all else.

In the majority of cultures (numerically, not by population) organ meats are the real prize from hunting, and the less nutritious muscle tissue is fed to the dogs.

The idea of eating liver, kidney or brain forces a lot of us to choke down the gag reflex, but it’s an under-appreciated fact that they’re an unbelievably potent source of an important class of nutrients: fat-soluble vitamins.   There’s a whole class of nutrients that need to be dissolved in fat in order to be absorbed by the body and organs are teeming with them.

Non-western uses of meat are also different in that they typically eat the whole frickin’ animal.  Most estimates suggest that extant tribes eat about 80% of the animal by weight, with organ meats having priority due to their unique nutritional value.  Other parts such as bones and intestinal lining are regularly used.

If you do the math, it’s easy to see that muscle meat contributes a small portion to even the most carnivorous bands of people.

For example, let’s generously estimate that 50% of the typical ancestral diet comes from animal sources.  If game, fish and insects are eaten in equal amounts and half of the calories from game come from its organs that means only 17% of all calories come from animal flesh.

5).  It Doesn’t Really Exist

Homo Sapien probably left Africa about 50,000 years ago.  Since then various sects of people have gone on to colonize almost every square foot of habitable land throughout the planet.  In places with no animals, in places with no plants, no sunlight, no nighttime, no rain, no snow, no……..you get the idea.

The vast diversity of human thought, appearances, and personality traits is a reflection of the fact that human evolution has diverged in dispersed groups in response to local conditions.

There’s every reason to believe that all sorts of people were eating all sorts of diets at the same time…..and still thriving.

Does this mean we can’t make generalizations?  Of course not.

There are plenty of things we can safely categorize as “healthy” or “unhealthy”, and many of the most important aspects of our physiology are conserved throughout the biological kingdom, which means they haven’t changed in millions of years.

But it’s also untrue to think that changes in our genome always happen at glacial pace.

In fact, there’s a lot of reason to think it’s the exact opposite.

Stephen Jay Gould is a famous biologist who posited that evolution doesn’t happen slowly, but incredibly quickly in short, almost violent bursts followed by periods of stability.  He coined the term punctuated equilibrium in order to describe it.

It’s been discovered that deliberate animal breeding can bring about significant genomic changes in about 10 generations and radical ones in as little as 30.

Of course this isn’t the case most of the time, but when selective pressures are strong important changes can spread through a population in short time (biologically speaking).   Our prolonged tolerance of lactose is a good example of how we’ve quickly evolved traits as a species in the last 10,000 years.

Human society has probably experienced more dramatic changes these last 5,000 years than anytime in the last 100,000, and our genome has evolved to reflect that, including changes to how we metabolize our food.

The geneticist John Hawks has posited that human genomic adaptation is accelerating due to population increases and more exposure to different environmental stimuli.  Some estimates suggest that as much as 14% of our genome has recently evolved (within the last 10-15,000 years).

I like the concept of paleolithic nutrition.  It’s the most useful guide for thinking about how to eat, and with a little creativity gives you a lot of wonderful options for enjoying your food.   It’s what I use to construct my own food choices. But it’s a mistake to think of it as a monolithic concept that maps 1:1 to how we can eat today.

Remember….the map is not the territory.