Chris Kresser: Your Personal Paleo Code

Humans were made to eat like Paleolithic hunter-gatherers, not farmers

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The following is an excerpt from Your Personal Paleo Code by Chris Kresser published Dec. 31, 2013 (Little, Brown and Company).

Agriculture: The Worst Mistake in Human History?

Like it or not, humans are animals.  And like all other animals, we are biologically adapted to a “species-appropriate” diet and way of life.

When animals eat and live in accordance with the environment to which they’re adapted, they thrive. Cats, with their sharp teeth and short intestinal tracts, evolved to be carnivores, so when we feed them grain-rich kibble, they develop kidney trouble and other woes. Cows naturally graze on grass; when they eat too much grain, harmful bacteria proliferate and make them sick. We humans face a similar mismatch. Our biology and genes adapted to a particular environment. Then that environment changed far faster than we could adapt—with a few important exceptions that I’ll cover later in this chapter. The result? The modern epidemic of modern, chronic disease.

For the vast majority of our existence, we humans lived as Paleolithic hunter-gatherers, living off the meat we hunted, fish we caught, and the vegetables, fruit, and tubers we picked while on the move. The Agricultural Revolution dramatically altered our food supply and way of life. We learned to stay put, planting crops and domesticating animals like cows, sheep, goats, and pigs. Early farmers consumed foods that their hunter-gatherer predecessors didn’t eat, such as cereal grains, milk and meat from domesticated animals, legumes, and other cultivated plants.

MORE: The Paleo Diet Craze: What’s Right and Wrong About Eating Like a Caveman

While scientists have argued that these developments allowed us to flourish socially and intellectually, the consequences of this shift from a Paleolithic to agricultural diet and lifestyle were disastrous for human health. In evolutionary terms, 11,000 years is the blink of an eye, not nearly long enough for humans to completely adapt to this new way of eating. This is why the influential scientist and author Jared Diamond has called agriculture “the worst mistake in human history.” He argued that hunter-gatherers “practiced the most successful and longest lasting lifestyle in human history” and were all but guaranteed a healthy diet because of the diversity and nutrient-density of the foods they consumed. Once we switched diets and became more sedentary, our naturally robust health began to decline.

Didn’t Our Paleo Ancestors Die Young?

A common question I hear from Paleo skeptics is something along the lines of  “Why should I eat Paleo?  Didn’t Stone Age people die before their thirtieth birthday?”

It’s true that, on average, our Paleo ancestors died younger.  However, these averages don’t factor in challenges largely absent from our modern lives: high infant mortality, violence and accidents, infectious disease and lack of modern medical care. Hunter-gatherers had infant mortality rates about 30 times higher than those in the US today—and early childhood mortality rates more than 100 times higher. These higher infant and childhood mortality rates were caused by accidents, trauma, exposure to the elements, violence, warfare, and acute infectious disease—issues that fortunately few of us face today. These untimely deaths had the net effect of dragging down average life expectancy. If out of 10 people, three died in infancy, two died during childhood from exposure to the elements and two died as teenagers in warfare, even if the remaining three lived long, healthy lives, the average lifespan in this hypothetical group would still be short.

Recent research that has taken the high infant mortality rates of our Paleolithic ancestors into account suggests that, if they survived childhood, they had average lifespans roughly equivalent to people living in industrialized societies, with a range from 68 to 78 years. Even more importantly, they reached these ages without any signs or symptoms of the chronic, inflammatory and degenerative diseases that we consider to be “normal” in developed countries – including obesity, type 2 diabetes, gout, hypertension, cardiovascular disease, and cancer. Sure, those of us living in modern, industrialized societies might live a little longer than acculturated hunter-gatherers on average. But most of our elderly people suffer from painful and debilitating diseases, take several medications a day, and have a decreased quality of life.

Fortunately, we don’t have to choose between eating like our ancestors or reaping the benefits of modern medicine. We can combine them to get the best both worlds and enjoy long lifespans without the degenerative diseases that are so common in the industrialized world.