Food

The evolution of human diet
The transition from vegetarianism to omnivory
The benefits of meat eating for humans
The introduction of cooking and the rise of hunting
Our 21st century physiology is overwhelmingly unchanged since the Pleistocene
Feeding our Pleistocene bodies in the 21st century
Notes on individual foods (listed alphabetically)
Notes on diets (on a separate page)

To begin with, let’s keep food in its evolutionary context and put aside for a while the cultural, social, emotional, religious, economic and representational aspects of food.

After all, food is basically fuel and it interests us because the best food leads to the best health.  Also, the evolutionary context covers millions of years, while the other aspects of food cover a relatively brief duration of time – too brief for our physiology to accommodate to them.  (It also interests us because we bring to food our own particular cultural, social, emotional, religious and representational baggage; try to keep these in perspective while you read through this page.)

Reach your arms out to each side, fingers extended.  Imagine that the distance from finger tips to finger tips represents the 5my of distinctly human evolution.

Now, if you trim the fingernails of your right hand, the extent your reach has been reduced would represent the proportion of those 5my during which people first started their transition from a hunter-gatherer economy to becoming settled cultivators of crops and farmers of animals.

Raise your arms again.  Look down along your arms to your hands at each side.  How important in your life, well-being, work and play are those arms, hands and fingers – and how insignificant for your life were those trimmed fingernails!

In the same way, for 5my of human evolution, our ancestors’ bodies and physiologies were shaped in thousands of important ways over a quarter of a million generations and selected for those variations which fitted them best to thrive in their environment.

The evolution of human diet
About 5 mya, the earth’s environment began a long period of cooling.  This caused rainforests to retreat, being replaced by open savannahs.  Those early humans best able to cope with the retreat of the rainforests (and their abundant fruit, nuts, insect larvae and vegetation biodiversity) by adapting to life on the forest edge (where variety was greatest) and the savannah (where grazing animals were the main hominid food source) were those who survived.  The fossil record shows that there were a number of different hominid species at this time, each evolving to fit an environment that provided food and other essentials matching their specialized survival needs.

But the rate of global climatic cooling was not steady.  There were fluctuations: ice ages, warmer periods, droughts and abundant rainfall.  Plant and animal populations, our ancestors’ food sources, also fluctuated and some hominid species failed to survive as their environmental niches disappeared.  Top

The transition from vegetarianism to omnivory
Raise your arms again.  If your left hand represents the time humans split from the common chimpanzee/human ancestor, the period represented by the length of your left arm represents 2.5 my of a primarily vegetarian diet, but progressively incorporating more meat – raw meat from scavenging rather than hunting.  The spread of savannahs was conducive to a spread of large grazing animals and, consequently, their predators.  This meant there were more large carcasses providing a significant food source for scavenging hominids.  The earliest humans were ‘opportunistic’ meaning that if it was edible and available, our ancestors used it.  That we are remarkably opportunistic omnivores is evidenced by the diversity and relative success of present-day human diets.

The benefits of meat eating for the genus Homo
The physiology we inherited from our common chimpanzee/human ancestor was suited to a vegetarian diet but also – fortuitously – enabled us to take advantage of the fats and proteins of the available meats: we benefited from our increasing omnivory.  As the hominids consumed more meat, they became less susceptible to environmental fluctuations.  They also developed larger bodies and larger brains, with the brains expanding particularly in the frontal cortex, the seat of intelligence and complex, social behaviours.  These adaptations to the environment and to the pressures of competition for limited food were marked by the emergence of the first member of the Homo genus: Homo habilis.  Human evolution from this time on became increasingly more a result of behavioural than physiological adaptation.  Physiological adaptation continued, but the huge evolutionary advances of our ancestors over the last 2.5 my were predominantly mental, social and behavioural adaptations.  Top

The introduction of cooking and the rise of hunting
With your arms outstretched again, think of your left arm as representing our vegetarian inheritance and the right arm as our more recent omnivory.  Looking down your right arm, your right elbow represents the earliest evidence of the controlled use of fire for cooking (from 1.2 mya) and the palm of your right hand (300,000 ya) the earliest hearths – evidence of regular fire use.  Somewhere in between your right elbow and fingers, our ancestors became active hunters, not just scavengers of the leftovers from lion kill.  Hunting large grazing animals is best achieved as a cooperative venture, and such cooperation requires the intelligence that came from larger brains fed fatty acids from breast milk coming from meat-eating mothers, consolidated through a life of meat eating.  At the tips of the fingers of your right hand, the fingernail overhang represents the last 10,000 years during which we ‘learned how to herd animals, grow grains and sit around’ (Tiger 2002).  No significant changes evolved in our physiology during this relatively brief recent period.

Our 21st century physiology is overwhelmingly unchanged since the Pleistocene
This 5 my history is too brief a period in evolutionary terms to transform a species physiologically.  Our bodies today are basically those that won through in the battle for survival in the African savannah.  They are not bodies adapted to a diet of grains and dairy foods, or a life without extreme physical exercise.  Top

Feeding our Pleistocene bodies in the 21st century
So, what food should we eat today, in the late Holocene?  How can we today recreate a Paleolithic diet?  Can we also recreate the concomitant Pleistocene environment to provide foods matching our physiology?

There are no hard and fast rules, but our approach to diet itself is important: learning and understanding about our evolutionary past and how diet and physical activity and even social activity are intertwined at both the physiological and the psychological level will help us make informed dietary choices that suit our needs.  If our Australopithecine ancestors had lived by a rule to eat only what had worked in the past, they would never have turned to meat and our line may well have become extinct.

On the other hand, let’s look at the characteristics of foods that could conceivably have contributed to our evolutionary survival and more effective adaptation to our emerging environment.  All foods would have been fresh, grown in an environment without significant pollution, chemicals – good or bad (including salt) – artificial fertilizers, antibiotics, preservatives, packaging, refrigeration.  Food would have been prepared and eaten without any regard for hygiene.  We would have gorged ourselves after butchering a large animal, selecting first the energy-rich fats and nutritious organ meat.  Then we would have gone hungry until the next carcass became available.  There would have been physical exertion (exercise) before eating – as we pursued, caught, killed, butchered and carried meat back to the tribe.  Vigorous exercise before food consumption would have been the rule, especially for males.

Here are a few considerations on specific foods (listed alphabetically) to guide you in creating your own Paleolithic diet.

Ask Evfit!  If there is a food about which you would like a second opinion, without the personal history and taste preferences you bring to the choice, please e-mail us at Evfit and we’ll add it to this page so you have our view of relevant factors you can take into account when you are deciding how to treat it in your diet.

My own food intake for a few selected days is here.

See also the Evfit page explaining why fats - as fats - don’t make you fat.

For a great high-fat snack that will keep you going for longer than any other food, try Pemmican.

References:
Audette – Neanderthin
Cordain – The Paleo Diet (2002)
Taubes – What if it’s all been a big fat lie? In the New York Times on 7 July 2002
Tiger – Against the Grain: the case for eating like a caveman.  In the Wall Street Journal, 14 July 2002
www.beyondveg.com

Evfit home    contact Evfit   On to pictures of a Paleo meal in preparation   On to detailed daily food intakes