Deadly Harvest: The Intimate Relationship Between Our Heath and Our Food (5 page)

Other researchers found that the San received healthy levels of vitamins A, B
₁₂
, C, and D, folate, thiamine, riboflavin, niacin, iron, calcium, iodine, zinc, copper, and other trace elements.
¹⁹
The human body is designed to manufacture vitamin D from sunlight. The San, like our African Pleistocene ancestors, lived in a sunny place and spent all day outdoors, with no clothes on. Their bodies manufactured all the vitamin D they needed. Nobody suffered from anemia or protein deficiency. The kidneys were functioning normally on the low-salt diet and were excreting very little salt in the urine. Levels of phosphorus in the urine were very low.

Lactose is a type of sugar found uniquely in milk. It is an aggressive allergen for most adults, although some Caucasians can put up with it. The San, in common with most peoples of the world, are uniformly intolerant of lactose. In glucose tolerance tests, the San had responses that are within the normal, non-diabetic range. Insulin response was slow, as is normal for humans who have virtually no sugars in the diet.

The San are in excellent health by any terms, let alone under the arduous conditions in which they live. Their old people live to a venerable yet healthy old age, in good shape right to the end. The “end” comes when they are too old to walk the 10 or so miles to the next campsite. The aged San makes contact with the spirits of his waiting ancestors. He is propped up under a bush with a supply of water, food, and weapons; he is surrounded with a thicket of thorny branches to keep the predators away. Sorrowful goodbyes are said and the band moves on. That is how it has always been, and there is nothing else to be done. After a day or two, the carnivores will snout the thorns aside and close in.

A Potent Lesson

For most of us, this lifestyle seems remote and outlandish, yet that is how our ancestors lived for endlessly cycling seasons in harmony with our African Pleistocene environment. Time is now out of joint and we have to make a mental leap to accept that the San’s present is a potent lesson about the past that shaped us. We have spent some time on the San for a very good reason: their lifestyle gives a very good picture of how our African Pleistocene ancestors lived for eons. It is the way of life for which our bodies are designed. Our studies of tribes like the San give a good picture of the kinds of foods that fueled the machine of our ancestral bodies. We are starting to get an idea of the composition of these foods and the proportions in which they were consumed.

The Australian Aborigine

Another example of a primal tribe, very remote from the San Bushman, is the Australian Aborigine, who lived a completely primal existence until European settlers first arrived in Australia 200 years ago. The continent of Australia has a wide variety of climates, ranging from tropical in the north to temperate in the south. The vast interior of Australia is very dry and much of it is desert.

Remarkably, in spite of the wide variation of climate and geography, the Aboriginal living arrangements hardly differed from the Bushman. They lived in bands of 30 to 50 people, men, women, and children included.
²⁰
Each group circulated in its territory, which could have an area of up to 300 square miles in barren regions. They were constantly on the move, camping for a few days and then moving on 10 to 15 miles to the next campsite.

How the Aborigines Feed Themselves

The basic food collecting patterns were similar to the San’s, especially in the savanna areas that mirror our African homeland.
²¹
The women gathered and the men hunted. The women used digging sticks and collected plants, insects, and small animals, providing the base load of food on a daily basis. The kinds of plants collected were quite different species to those of the Kalahari, but had very similar characteristics: young leaves and shoots, roots, tubers, bulbs, fibrous fruits, nuts, gums, flowers, water lily roots, and berries.

The animal food collected would be eggs, turtles, snakes, shellfish, crabs, caterpillars (e.g., the witchety grub and the bogong moth), land snails, and the goanna (a giant lizard). Sweet foods were very rare but much prized. Disproportionate amounts of time were spent on finding a bees’ nest to smoke out. Other sweetmeats were the honey ant, gorged with nectar, and “lerp,” a sweet insect secretion on eucalyptus leaves. In times of scarcity, grass seeds were collected, winnowed, and ground between two handheld stones.
²²
The drudgery of this task was viewed with such distaste that it was only done very rarely.

The men would spend a lot of thought, ingenuity, and time on the hunt, which was often unsuccessful. Stories about the hunts, past, present, and future dominated their conversations. Unlike the San, the Aboriginal did not have the bow and arrow—they still used spears, traps, snares, boomerangs, and fire. They hunted and trapped wallaby, kangaroo, freshwater fish, snakes, platypus, possums, birds, ducks, and emu.

The Aboriginal Food Supply

The Aboriginal food supply was similar to the San in the proportion of food coming from animals and plants. About 35% of calories came from animal sources and 65% from plant sources. In traditional aboriginal diets, the animal matter was very low in fat (less than 3%).
²³
It was mainly polyunsaturated fat, and there was little saturated fat. The polyunsaturated fat was composed of equal percentages from the omega-3 and omega-6 families. As with the Bushman, fat was much sought after: fatty parts of the carcass were prized, distributed with ceremony, and eaten with relish. The witchety grub was rich in monounsaturated fat, similar to olive oil.

The State of the Aborigine’s Health

At the time of European settlement 200 years ago, the Aboriginal was described as being in good health and of athletic physique. In the 1960s, researchers studied Aboriginals still living the traditional way and found that they were incredibly lean by our standards, with body mass indexes ranging from 16 to 20.
²⁴
They also had low blood pressure, low cholesterol, and no atherosclerosis or diabetes. Their blood samples showed high levels of hemoglobin, vitamins C and B12, folate, and a good sodium/potassium ratio. However, the Aborigines’ health disintegrates when they adopt a European lifestyle.

Fossil Evidence

We have looked at what primal tribes do today; but what can we learn directly about our ancestors who lived in African Pleistocene times? Ancient bones are a rich source of a surprising amount of information. Rutgers University anthropologist Robert Blumenschine and others have discovered that Stone Age humans were scavengers.
²⁵
He and other researchers excavated the fossilized bones of butchered carcasses. By clever analysis, they found that the marks from the stone chopping tools came
after
the marks from the predator that did the killing. In other words, the lion killed his prey and took his fill, then the humans rushed in to fight the hyenas for the leftovers. As anthropologist Pat Shipman observed, “meat-eaters scavenge when they can and hunt when they must.”
²⁶

However, there is more to bones than just the marks on them. A person builds bones from the foods that he or she eats, so it is possible to analyze the chemical composition of a bone to find out the foods eaten to make that bone. Michael Richards, a specialist in prehistoric diets from the University of Bradford, finds that, 30,000 years ago, the Cro-Magnons of Europe ate fish, turtles, shellfish, and birds.
²⁷
Meanwhile the Neanderthals, who lived alongside them, ate reindeer, mammoth, and other large herbivores.

Ancient teeth are another rich source of information. Have you ever wondered why your back teeth have those difficult-to-clean biting surfaces? Dental researchers like Peter Lucas and W. Maier studied what is so special about these shapes. They find that they are best for grinding up plant food; on the other hand, they are not very good for meat or seeds.
²⁸
Other researchers have examined the tooth enamel and find that the thickness and strength of human enamel is designed for a plant food diet that is halfway between that of a chimpanzee and a gorilla.
²⁹
A chimpanzee eats mostly soft plant foods like fruits and tender leaves, while a gorilla eats tough leaves and even twigs and branches.

Yet other researchers look at the scratches and wear on ancient teeth. The Spanish biologist Carles Lalueza and others find that Neanderthals have tooth wear typical of a meat diet.
³⁰
In contrast, the teeth of African Pleistocene humans show that they were eating an abrasive, high plant food diet.

Remarkably, fossilized excrement, known as coprolite, has been discovered and is a good source of information. Michael Kliks, a specialist in intestinal health, has studied ancient coprolites and reports that, until quite recently, human populations took in impressive amounts of plant fiber—around 130 grams per day.
³¹
Fascinatingly, also in the fossilized excrement, he found undigested residues of bones, teeth, hair, feathers, fish scales, and insect shells.

Up to this point, we have been examining direct
evidence—data that we can measure directly and is fundamental to understanding our ancestral nutritional heritage. It paints a picture of human beings as a species and gives strong guidance to our naturally adapted feeding patterns. But we must also take into account other fields of scientific research which have an
indirect
bearing. This is a demonstration of our approach set out at the beginning—to break across barriers between scientific compartments and bring a satisfying harmony to the totality of knowledge. Understanding this circumstantial evidence brings unexpected insights on a whole range of perplexing health mysteries. Here, we look at some of this intriguing indirect, or circumstantial, evidence.

The Path of Least Work

The review of foraging tribes such as the San and Aborigine sets the scene for understanding the kind of lifestyle led by our ancestors for eons. One factor that emerges very strongly is that humans are
economical
with their energy. They seem to have a calculator in their heads, whirring away, working out what is the best return for the effort they spend. This is known as finding “the path of least work” to get what they want. (No surprises there!) In terms of finding food, this is known as “optimal foraging” strategy. Very simply, how does a human being efficiently find food in the African savanna with only bare hands, a pointed stick, and loads of ingenuity?

Several studies have examined the effort compared to the benefit for various feeding patterns. Not surprisingly, they find that, overall, it requires the least effort to collect foodstuffs that stay still or only move very slowly. Therefore, plants of all kinds, eggs, and slow-moving animals provide the vast bulk of the diet. In addition, foods that require little or no
processing
are given top priority. As we saw, the Aboriginal only ate grass seed as a last resort; it was just too time-consuming and tedious.

These optimal foraging analyses all reinforce our picture of the true eating pattern practiced by the San and Aboriginal. However, it begs the question why humans bothered with
hunting
at all: it is dangerous, it requires lots of energy, and the results are uncertain. Worse, the hunter, instead of finding dinner, could
become
dinner! The answer to this fascinating question is explored in Chapter 6.

What Kind of Food is Our Digestive System Designed For?

Another piece of indirect evidence comes from answering the question, “What kind of food is the human digestive system designed to operate on?” After all, we know that a canary eats birdseed but a cat eats canaries—and they each have a digestive system and enzymes to suit their particular natural diets. One illuminating approach is to take a critical look at creatures that are most similar to us in biological terms.

The closest relatives to humans in the evolutionary tree are the chimpanzee and the gorilla. Since we share the same lineage, we can expect to share similar, if not identical, eating habits too. At the very least, our digestive systems will share a common heritage, even if they have been pressed into slightly different uses since our ancestral lines diverged. Several groundbreaking studies, including those by the geneticists Charles Sibley,
³²
Jeffrey Rogers,
³³
and Morris Goodman
³⁴
show that the chimpanzee and the gorilla share over 98% of their DNA with human DNA. Their body plan is almost the same as each other’s and ours.