Back in 1985, a then-obscure physician published a paper in the New England Journal of Medicine titled, “Paleolithic Nutrition: A Consideration of Its Nature and Current Implications.” The author, Dr. Boyd Eaton, argued a simple yet elegant theory. To quote from a later review paper he authored:

“The nutritional needs of today’s humans arose through a multi-million year evolutionary process during nearly all of which genetic change reflected the life circumstances of our ancestral species. But since the appearance of agriculture 10,000 years ago, and especially since the Industrial Revolution, genetic adaptation has been unable to keep pace with cultural progress.”

Eaton argued that those last 10 millennia have produced little in the way of consequential genetic alterations of human physiology, such that we humans are still nutritionally best adapted to eat what our Paleolithic Age ancestors ate millions of years ago.

Which, to be sure, was a lot heavier on fresh meat and fish and a lot lighter on such vegetarian specialties of processed soy protein and jet-freighted fruits and salad ingredients.

That’s to be expected when you live in caves and spend your waking hours hunting wild animals with stone-tipped spears and sharpened sticks.

According to Eaton’s research, the Paleo diet not only contained plenty of meat, but also highly nutritional wild roots, greens and other “uncultivated” fruits and vegetables. Surprisingly—especially for the veggie believers who condemn any amount of meat-eating—the typical Paleo diet that sustained our earliest human ancestors, best as can be estimated, provided about 35% to 37% protein, about 40% Complex carbohydrates and no more than 25% fat.

Even by contemporary nutritional standards, that’s a pretty healthy, well-balanced diet, one that compares favorably with USDA’s current recommendations.

Not by diet alone

Fast forward a couple decades from Dr. Eaton’s groundbreaking study, and the Paleo diet appears to be making a comeback. In the midst of an unprecedented wave of rhetoric and advocacy for various vegetarian diets (and lifestyles) Paleo diet enthusiasts contend that a diet of meat, root and green vegetables and fish—along with lots of exercise—is the ticket to optimal health and well-being.

As part of its extended review of meat-eating in our modern age, National Public Radio this week featured John Durant, a Paleo diet enthusiast who is authoring a book on the diet. He told NPR that, “For millions of years, we didn’t have an obesity problem because we ate foods that our metabolism was adapted to. We were active and lived a healthy lifestyle.”

That last comment is key: Activity. It’s almost impossible to dissect the value of a Paleo diet without factoring in not just the rigors of hunting, butchering and cooking the meat that sustained the homo sapiens who inhabited the world hundreds of thousands of years ago but the effect of spending all day, every day out in the wind, cold and other weather extremes without benefit of heat pumps, air conditioners and climate-controlled automobiles.

Most paleoanthropologists acknowledge that humans evolved and became adapted to eating meat. There’s no question about that, given the relative abundance of evidence—bones scraped clean, the remains of fire pits and various stone tools used as weapons and for skinning and cutting up animal carcasses.

The question NPR cares about is this: Should we be mimicking the Paleo diet today, given the realities of contemporary lifestyles?

According to its proponents, there are three reasons why such a dietary plan makes sense:

  • Conceptually, a diet in tune with human biology carries significant scientific validity
  • Nutritionally, animal protein (with rare exceptions) is an outstanding source of essential protein and minerals for virtually everyone
  • And as a practical matter, a diet that simply says eat as much fresh meats, seafood, fruits and veggies as one’s appetite dictates makes long-term compliance far more likely

The key is that a Paleo diet, to be effective, needs to be coupled with a rigorous program of activity and exercise. One of the most vocal sources of support for the diet is coming from the growing ranks of fitness enthusiasts, who all claim that eating in accordance with its principles results in losing body fat, gaining muscle strength and endurance and experiencing improvements in virtually all significant health indices, such as blood pressure, body mass index and maintenance of ideal weight for one’s age and gender.

To be sure, no diet is a panacea for all the “lifestyle diseases” that ail Homo postmodernus. Without the complementary component of high levels of vigorous activity, it really doesn’t help to eat either large amounts of animal or vegetable protein. Neither by itself assures optimal well-being.

More importantly, even among athletes and fitness proponents, ads come and go. For example, in the late 1960s, a wave of “exercise gurus” proposed that a vegetarian diet was the healthiest choice for endurance athletes. Shortly afterwards, the “carbo loading” craze took off. Of course, the science supporting the idea that stuffing yourself with pasta the day before running a marathon was the ticket to success was non-existent, and that approach was eventually discredited.

The takeaway from a renewed focus on the Paleo diet isn’t all about eating meat, rather than vegetarian alternatives. It’s about understanding how our primitive ancestors actually lived.

We’d all be better off if we spent more time outdoors, got much more exercise, especially long-distance walking ,and had hobbies that involved lots of heavy lifting and vigorous activity—say, something along the lines of skinning and butchering a wooly mammoth.

Eating lots of meat would be a bonus that would accompany such a lifestyle adaptation.

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.