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Paleolithic

nutrition:whatdid our ancestors

eat?Janette Brand MillerNeil Mann

Loren Cordain



Paleolithic nutrition is the study ofdiets consumed by our early ‘stone

age’ ancestors, members of our spe-cies who lived from around 750,000

years ago up until 10,000 years ago (Figure 1).During this period, hominids relied on stonetechnology to sustain their scavenging, huntingand gathering lifestyle (Figure 2). Paleolithicdiets are a subject of interest for various reasons. Apart from the intrinsic value of knowing moreabout our past, many health experts have sug-gested that the ‘native diet’ during human evolu-

tion is the healthiest diet, the one that meetsall our nutritional needs and to which we aregenetically adapted. Just as veterinarians try togive zoo animals a diet closest to that which theyconsumed in the wild, many nutritionists believethat the diet eaten for the greater part of one mil-lion years of human evolution is the ideal diet.Conversely, they believe that modern illnessessuch as type 2 diabetes and coronary heart dis-ease are a consequence of eating a diet to whichwe are not genetically adapted (Figure 3). Thelast 10,000 years ago (a mere ‘tick’ on the evolu-tionary clock) have brought near inconceivablechanges to diet and physical activity.



30 | Genes to Galaxies

First stone tools appear in the fossil

record ~2.4 MYA

Why were they

made? What were

they used for?

Butchering of

scavenged animals

Flakes for slicing

Core for chopping

Paleolithic Nutrition

Prof. Jennie Brand-Miller Human Nutrition Unit

Native Diet of Our Closest

Living Relative

94% plant foods

chiefly ripe fruit

6% animal foods - smallvertebrates & insects

A large metabolicallyactive gut is needed toprocess large amountsof less energeticallydense, fibrous plantfoods

Transition from Ape to Human

Bipedalism

Opposable thumb

Reduction in bodyhair

Increase in brain size& complexity

Decrease in gut size& metabolic activity

Discordance Hypothesis

The discordance

between modern diets

and paleolithic diets

contributes to manydiet related health

problems of modern

man

African Climate20 MYA and 7 MYA

Declining rainfall…. Contraction of rainforest

Figure 1

Figure 3

Figure 5

Figure 2

Figure 4

Figure 6



Paleolithic nutrition: what did our ancestors eat? | 31

Climate dictates food sources

For most of geological time, the world’s climatewas warmer and more homogeneous than itis today (Figure 4). Our pre-human ancestorswho lived in Africa >7 million years ago en- joyed a warm, moist environment and gathered

ripe fruits, leaves and berries from the tropicalforests (Figure 4 and 5). But gradually the plan-et cooled. About 2.5 million years ago, a severeIce Age sent global temperatures plummetingand prompted the conversion of moist Africanwoodland into much drier open savanna. Asthe grasslands expanded, the tree cover shrankand one or more species of forest dwellingchimpanzee evolved into bipedal hominids(Figure 6). Homo habilis who lived 2 million

years BP supplemented a largely vegetarian dietwith meat left over from predators’ kills (i.e.they scavenged). But Homo erectus who lived1.5 million years BP is known to have activelyhunted. Many scientists believe that huntingwas the pressure that selected for the larger andlarger brain of our species, Homo sapiens sapiens(the phrase “man the hunter” originated withthis idea)(Figure 7 and 8).

As one Ice Age followed another, hunting and

fishing became a dominant way of life in bothwarm and cold environments. During Ice Ages,large amounts of water become locked intothe polar ice caps, making the whole planetdrier because less water falls as rain and snow.Plant growth slows, rainforests shrink andgrasslands dominate the landscape. Herbivorescame into their own and grazing animalsmultiplied in their millions. From 50,000years ago, we know that Neanderthals werecold-climate hunters of large game. Indeed,over winter they subsisted primarily on game.One large mammoth kill would have nourisheda family group of 50 individuals for at least3 months. Similarly, Cro-Magnon man whoreplaced the Neanderthals about 35,000 yearsago, lived through the coldest of the Ice Ageson a high meat diet. The Hall of Bulls in thefamous Lascaux Caves in southern France is atestament to the importance of animals to thepeople who lived 17,000 years ago (Figure 9).

Similarly, we know that the ancestors of the Aborigines who inhabited Australia 40-50,000years ago led a hunting and shellfish gathering

existence. Even during the warm inter-glacials,parts of the world remained cold (e.g. Arcticand sub-arctic regions) and continued to havelittle vegetation. The human inhabitants ofthose regions maintained a hunting/fishingexistence right up to recent times. Indeed, theInuit and other native Canadians are a modernday example of a group whose historic diet washigh in animal food and low in plant matter.

During the early and mid 20th century, anthro-pologists studied the planet’s few remaininghunter-gatherer societies. To their surprise,they found them generally free of the signsand symptoms of the so-called diseases ofcivilization. Although their nutritional patternsprobably would not have been identical to

hominids living during the Paleolithic period,they represent the best ‘window’ we have intothe range and quantity of wild and unculti-vated foods making up humanity’s ‘native’ diet.Consequently, the characterization and descrip-tion of hunter-gatherer diets has importantimplications in designing therapeutic diets thatreduce the risk for chronic diseases in modern,western cultures.

These ethnographic and anthropological stud-

ies tell us that there was no single, uniformdiet which typified the nutritional patternsof all pre-agricultural humans. Humans weremasters of flexibility, with the ability to live in arain forest or near the polar ice caps. Yet, basedupon limited information, many anthropolo-gists incorrectly concluded that the universalpattern of subsistence was one in which plantfoods contributed the majority of food energy.However, more recent and comprehensiveethnographic compilations (Cordain et al,2000a) as well as quantitative dietary analysesin foraging populations, have been unable toconfirm the conclusions of these earlier studies.In fact, the later studies demonstrated that ani-mal foods, rather than plant foods, comprisedthe majority of energy in the typical hunter-gatherer diet.

Unfortunately, in the context of western diets,increasing meat consumption (particularlyred and processed meat) is linked to a greaterrisk of cardiovascular disease. In countries likethe USA, meats contribute much of the fat,




Inclusion of more animal food in the

diet allowed brain to enlarge

How?

Humans expend 20-25% ofRMR to fuel the brain whereas

chimps require 8%

Two possibilities:

(1) increases in total metabolic

rate

(2) reduction in size &

metabolic rate of another

organ Aiello LC Wheeler. The expensive tissue

hypothesisCurr Anthropol 1995 36:199-22

Evidence of Complex Big Game

Hunting in Homo Sapiens

Anatomically modern

H. sapiens appear(~100,000 yrs ago)

A spear point was

found lodged in the

vertebra of a giant

buffalo at Klasies River

Cave, South Africa

(60-120,000 yrs ago)

Dependence on gathered plant foodsFrequency Distribution of Subsistence Dependence (n = 229)

11

35

4245

35

30

23

6

20

0

5

10

15

20

25

30

35

40

45

50

F r e q u e n c y

% Dependence

0-5 6-15 16-25 26-35 36-45 46-55 56 -65 66-75 76-85 86-100

On average, plant

foods contributed

25-35% of energy

Only 13% obtained

more than half their

energy from plant

foods

Dependence on hunted animal foodsFrequency Distribution of Subsistence Dependence (n = 229)

0

8

36

89

47

21

11

5

9

3

0

10

20

30

40

50

60

70

80

90

100

F r e q u e n c y

% Dependence

0-5 6-15 16-25 26-35 36-45 46-55 56-65 66-75 76-85 86-100

Mode = (26-35%)

Median = (26-35%)

On average,

hunted animal

foods contributed26-35% of energy

Hall of Bulls -Lascaux Cave,France (17,000 yrs ago) Plant Foods

How important

(quantitatively) weregathered foods in the diets

of pre-agricultural humans?

Only quantitative evidence

comes from observations of

early ethnographers who

studied world’s ‘remnant’

hunter-gatherers

Figure 7

Figure 9

Figure 11

Figure 8

Figure 10

Figure 12




and more importantly, about one third of thesaturated fat, the kind mostly clearly linkedto adverse outcomes. Thus, a high meat diet,regardless of its fat quantity and type, is gener-ally perceived to be unhealthy and to promotecardiovascular and other chronic diseases. Yet Australian red meat derived from grazinganimals is generally lean, low in saturated fatand contains significant amounts of healthylong chain omega-3 fats. Our research providesevidence that the animal foods that dominatedhunter-gatherer diets were also low in saturatedfat and high in good fats. This nutritional pat-tern would not have promoted atherosclerosis(hardening of the arteries) or chronic disease.

Confusion over pre-agricultural diets

Early theories on the natural, or native hu-man diet assumed that Paleolithic people wereskilled hunters of big game whose diets wereprimarily carnivorous in nature. However, byearly 1970s, this “Man the Hunter” explana-tion was being contested by Richard Lee andother anthropologists on the basis of evidencesuggesting that contemporary hunter-gathererpeoples consumed more gathered plants thanhunted animal food (Lee, 1968) (Figure 10).For example, Lee’s studies of the African !Kungpeople demonstrated that gathered plant foodscomprised 67% of their average daily energyintake while hunted animal foods encompassedthe remaining third. Lee further compiled datafrom 58 hunter-gatherer societies who werelisted in the Ethnographic Atlas (Murdock,1967), showing that hunted animal food madeup only 35 per cent of food intake, irrespective

of latitude.

Over the next 30 or so years, Richard Lee’sanalysis was widely misinterpreted to meanthat gathered plant foods typically providedthe major food energy in worldwide hunter-gatherer diets, while hunted animal foods madeup the balance. But this general perceptionis incorrect because fished animal foods mustbe summed with hunted animal foods in theanalysis of the ethnographic data to more cor-

rectly evaluate dietary plant to animal energyratios (i.e. the percentage of energy contributed

by plants versus animal foods). Our analysis(Figures 11-14) of Gray’s Ethnographic Atlas data (Gray, 1999) showed that the dominantfoods in most hunter-gatherer diets were de-rived from animal food sources. We found thatnearly 3 in 4 of the world’s hunter gathererpopulations obtained at least half of their foodenergy from hunted and fished animal foods,whereas fewer than 1 in 7 obtained more thanhalf their calories from gathered plant foods.Not a single hunter-gatherer society was com-pletely vegetarian. The statistical mean amongall 229 hunter-gatherer societies in Gray’s atlasindicated that 68% of calories came from ani-mal foods and 32% from gathered plant foods(Figure 15).

Quantitative studies ofhunter gatherer diets

The major limitation of ethnographic data isthat much of the information is subjective innature. Murdock’s scoring for the five basicsubsistence economies in the Ethnographic Atlas were approximations, rather than preciselymeasured food intake data. Fortunately, moreexact, quantitative dietary studies were car-ried out on a small number of hunter-gatherersocieties. Table 1 lists these studies and showsthe plant to animal subsistence ratios. Themean score for animal food subsistence is 65%,while that for plant food subsistence is 35%.These values are similar to our analysis of theentire (n = 229) sample of hunter-gatherersocieties (Figure 15). If we exclude the twopolar hunter-gatherer populations (who haveno choice but to eat animal food because ofthe inaccessibility of plant foods) from Table 1,

the mean score for animal subsistence is ~60%and that for plant food subsistence is ~40%.Consequently, there is remarkably close agree-ment between the quantitative data in Table 1and the ethnographic data.

Other evidence for meat eating

Isotope studies of fossil bones can tell us moreinformation about the type of foods that ourancestors ate. Isotopic analysis of the skeletonsof Neanderthals (Richards et al, 2000a) andPaleolithic humans (Richards et al, 2000b)




Dependence on fished animal foodsFrequency Distribution of Subsistence Dependence (n = 229)

36

23

37

34

30

38

21

5 5

0

0

5

10

15

20

25

30

35

40

F r e q u e

n c y

% Dependence

0-5 6-15 16-25 26-35 36-45 46-55 56-65 66-75 76-85 86-100

Mode = (46-55%)

Median = (26-35%)

On average, fishing

contributed 26-35%

of energy

Total dependence on animal foods

(hunted + fished)

0 0 2

6

23

30

35

45

42

46

0

5

10

15

20

25

30

35

40

45

50

F r e q u

e n c y

% Dependence

0-5 6-15 16-25 26-35 36-45 46-55 56-65 66-75 76-85 86-100

Mode = (66-75%)

Median = (86-100%)

On average, all

animal foods

(hunted and fished)contributed >66%

of energy

Dietary Macronutrients Hunter Gatherer vs Modern Values

CHO

22-40 %

Protein19-35 % Fat28-47 %

Hunter Gatherer Societies

n=133 (58.1%)

Fat34%

Protein

15%

CHO

49%

Present USA Values

NHANES III

ETOH-

3%

Recommended Dietary

Macronutrient Intake

CHO

55% or more

Fat30% or less

Protein

15%

American Heart Association

Recommended Diet

Plant:Animal RatiosHunter Gatherer Modern Diets

62 %

Plant

Food

38 %

Animal

Food

National Food ConsumptionSurvey 1987-88

Mean values,229 Hunter Gatherer

Societies

68 %

Animal

Food

32 %

Plant

Food

Foods not present in pre-agricultural diets

Breads, Cereals, Rice and Pasta Dairy Products Added Salt

Refined Vegetable Oils Refined Sugars

(except honey)Alcohol

Figure 13

Figure 15

Figure 17

Figure 14

Figure 16

Figure 18




suggests that the dominance of animal foodsin the human diet was not simply a recentphenomenon limited to contemporary hunter-gatherers, but rather one with a long history.These studies provide objective evidence thatthe diets of hominids living in Europe during

the Paleolithic were indistinguishable from thatof carnivores such as arctic foxes and wolves.Indeed, hominids may have experienced genet-ic adaptations to animal-based diets early on intheir evolution, analogous to those of obligatecarnivores such as cats (felines).

Carnivorous diets reduce the evolutionaryselective pressures that act to maintain ana-tomical and physiological features needed toprocess and metabolize large amounts of plant

matter. Like cats, humans have experienceda reduction in gut size and metabolic activity,along with a concurrent expansion of brainsize (Figure 7). This occurred at the very sametime that more and more energetically denseanimal food was incorporated. The brain is avery energy-demanding organ, responsible forabout one quarter of our basal metabolic rate.Further, similar to obligate carnivores, humanshave a limited ability to manufacture the longchain, highly polyunsaturated fatty acids thatcharacterize our complex brain and nervoussystem. Long chain polyunsaturated fatty acids

are essential cellular lipids that are found onlyin animal foods. The implication is that by eat-ing abundant pre-formed sources of these fattyacids, our bodies gradually lost the ability tosynthesise them ‘in house’.

Finally, our species (again like cats) has a

limited capacity to synthesize the aminoacid taurine from its precursor amino acids. Vegetarian diets are known to result in lowerblood concentrations of taurine. This impliesthat the need to synthesize taurine may havebeen unnecessary because dietary sources ofpre-formed taurine had relaxed the selectivepressure to maintain the metabolic machinery.

There are additional signs that we were grow-ing dependent on animal food sources. One of

our essential micronutrients is Vitamin B12 andfound only in animal foods. Similarly, the rich-est sources of iron, iodine, folic acid and vita-min A are animal foods. The most common nu-trient deficiencies today are associated with lowmeat consumption. Iron deficiency anaemiais prevalent in both rich and poor countries,while iodine deficiency affects up to 2 billionpeople world wide, resulting in goitre, cretin-ism and enough mental retardation to reduce

a population’s average IQ. (Incidentally, iodinedeficiency is rising sharply in Australia becausedairy manufacturers no longer use iodophors as

Table 1: Quantitatively determined proportions of plant and animal food in hunter-gatherer diets.

Population Location Latitude % animal food % plant food

Aborigines Australia 12S 77 23

Ache Paraguay 25S 78 22

Anbarra Australia 12S 75 25Efe Africa 2N 44 56

Eskimo Greenland 69N 96 4

Gwi Africa 23S 26 74

Hadza Africa 3S 48 52

Hiwi Venezuela 6N 75 25

!Kung Africa 20S 33 67

!Kung Africa 20S 68 32

Nukak Columbia 2N 41 59

Nunamiut Alaska 68N 99 1Onge Andaman 12N 79 21




cleansing agents in dairy factories). Folic aciddeficiency causes a birth defect in which thebrain and spinal cord do not develop normally,a condition known as ‘neural tube defect’. Although dark green leafy vegetables are a goodsource of folic acid, the very richest source isanimal liver, a commodity regularly consumedby our hunter-gatherer ancestors. Finally, hu-mans have a finite capacity to convert the yel-low/orange coloured carotenoids in plant foods

into vitamin A. Today, vitamin A deficiencyblindness is the most common cause of visionloss in the world and again, the richest sourcesof vitamin A are liver and animal flesh. Sogradually, but surely, we evolved a metabolismthat depended on at least moderate intake ofanimal foods.

Hunter-gathererforaging strategies

Our analyses of both the ethnographic data andthe quantitative dietary data (Table 1) showthat animal foods were our preferred energysource, even when plant food sources wereavailable year round such as in the tropics.Only when it was difficult to procure animalfood sources, or when energy-dense, easilyprocured plant foods were available (eg themongongo nut for the South African !Kungpeople), did plant foods prevail as a major en-

ergy component in hunter-gatherer diets.

Foraging humans are similar to other animalsin natural settings in that they attempt tomaximize the energy ‘capture’ rate, i.e. theratio between the energy obtained from a foodsource compared to the energy expenditureneeded to acquire it while hunting, fishingor gathering (this is known as the OptimalForaging Theory). Table 2 shows the energyreturn rates for a variety of plant and animalfoods that were known components of hunter-

gatherer diets. Clearly, animal foods yield thehighest energy return rates, and larger animalsgenerally produce greater energy returns thansmaller animals. Although the potential foodmass would be similar between a single deerweighing 45 kg and 1,600 mice weighing 30 geach, foraging humans would have to expendsignificantly more energy capturing the 1,600mice than a single deer. Hence, the killing oflarger animals increases the energy capture/

energy expenditure ratio not only because itreduces energy expenditure, but because it in-creases the total energy captured.

Due to the relative constancy of the proteincontent of an animal’s muscle mass, the energydensity of an edible carcass is almost entirelydependent upon its body fat content. Varyingamounts of body fat determine the protein tofat energy ratio in an edible carcass. Becausesmaller animal species have proportionately

less body fat than larger species, their carcassescontain more protein as a percentage of theiravailable food energy. Hunter-gatherers tended

The USDA Food Pyramid

Fats Oils & Sweets

use sparingly

Milk, Yogurt & Cheese

2-3 Servings

Vegetables

3-5 Servings

Bread, Cereal, Rice

& Pasta

6-11 Servings

Fruit

2-4 Servings

Meat, Poultry, Fish, Dry Bea

Eggs & Nuts

2-3 Servings

Human Evolutionary Food Pyramid

Figure 19 Figure 20




to shun very small animals or fat-depleted ani-mals because of their excessive protein content.Historical accounts documented the adversehealth effects that occurred when people wereforced to rely solely on fat-depleted, wild ani-

mals (Speth & Spielmann, 1983). Excessiveprotein consumption without additional sourc-es of fat or carbohydrate caused a condition de-scribed as “rabbit starvation” in early Americanexplorers. They suffered nausea, diarrhea andeven death if very lean small animals were theonly source of food. Clinically, this syndromeis probably caused by the finite ability of theliver to up-regulate the rate-limiting enzymesthat synthesise urea, culminating in very high

levels of ammonium ions and acidic aminoacids in the blood. For the foraging human, theavoidance of excessive dietary protein was an

important factor in shaping their food procure-ment strategies. Lean meat, therefore, couldnot be eaten in unlimited quantities, but ratherhad to be accompanied by sufficient fat, or bycarbohydrate derived from plant food sources.

This simple physiological fact could explainour innate drive to consume fatty and sweetfoods.

Modern vs traditionalfood choices

Before the development of agriculture andanimal husbandry, dietary choices would havebeen limited to minimally processed, wild plant

and animal foods. With the initial domestica-tion of plants and animals, the original nutrientcharacteristics of foods changed, subtly at first

Table 2: Energy return rates upon encounter from foraged foods.

Food Food Type Return rate (kcal/hr)

Collared peccary Animal 65,000

Antelope, deer, bighornsheep

Animal 16,000 – 32,000

Jack rabbits Animal 13,500 – 15,400Cottontail rabbits, gophers Animal 9,000 – 10,800

Paca Animal 7,000

Coati Animal 7,000

Squirrel (large) Animal 5,400 – 6,300

Roots Plant 1,200 – 6,300

Fruits Plant 900 – 6,000

Armadillo Animal 5,900

Snake Animal 5,900

Bird Animal 4,800Seeds Plant 500 – 4,300

Lizard (large) Animal 4,200

Squirrel (small) Animal 2,800 – 3,600

Honey Plant 3,300

Ducks Animal 2,000 – 2,700

Insect larvae Animal 1,500 – 2,400

Fish Animal 2,100

Palm heart Plant 1,500

Acorns Plant 1,500

Pine nuts Plant 800 – 1,400+Mongongo nuts Plant 1,300

Grass seeds Plant 100 – 1,300




but more rapidly with advancing technologyafter the Industrial Revolution. Food processingprocedures were developed which had pro-found physiological implications.

Today we eat many types of food that wereabsent from the diet of Paleolithic people.

Dairy products, cereals, refined sugars, refinedvegetable oils, and alcohol make up over 70%of the total daily energy consumed by people indeveloped nations (Figure 16). But these typesof foods would have contributed little or noneof the energy in the typical pre-agricultural hu-man diet. Additionally, mixtures of foods thatmake up much of our present diet (eg, cookies,cake, breakfast cereals, bagels, rolls, muffins,crackers, chips, snack foods, pizza, soft drinks,

candy, ice cream, condiments, and salad dress-ings) were absent.

Dairy foods Humans, like all mammals, wouldhave consumed the milk of their own speciesduring infancy. However, after weaning, theconsumption of milk and milk products ofother mammals would have been minimal.Sheep, goats and cows were not domesticateduntil ~10,000 years ago and direct evidence ofdairying dates to only ~6000 years ago. Most of

the world’s population still does not consumemilk beyond infancy. It should not be surpris-ing therefore to learn that more than 80% ofhumans do not have the capacity to hydrolyselactose, the carbohydrate in milk, after earlychildhood. However, European Caucasians andtheir descendents in America and Australia,who have been exposed to dairying for severalthousand years, can generally digest lactosewell throughout life.

Cereals Wild cereal grains are usually small,difficult to harvest, and virtually indigestiblewithout processing (grinding) and cooking. Forthis reason, Paleolithic people ate little of them.Grinding tools in the fossil record represents areliable indication of when and where cultures

began to include cereal grains in their diet.

Ground stone mortars, bowls, and cup holesfirst appeared from 40,000 years ago to 12,000years ago. Domestication of emmer and einkornwheat heralded the beginnings of early agricul-ture in southeastern Turkey about 10,000 yearsago. There was therefore little or no previous

evolutionary experience for cereal grain con-sumption throughout human evolution. Again,it should not be surprising to learn that manypeople are allergic to the gluten protein foundin wheat, rye and barley. Known as celiacdisease, it causes the body’s immune system toattack itself and affects more than one in every133 people.

Today, most cereals consumed in the west-ern diet are highly processed refined grains.Preceding the Industrial Revolution, all cerealswere ground with the use of stone milling tools,and unless the flour was sieved, it containedthe entire contents of the cereal grain, includ-ing the germ, bran, and endosperm. Withthe invention of mechanized steel roller mills

and automated sifting devices in the latter

part of the 19th century, the nutritional andphysiological characteristics of milled grainchanged, becoming virtually pure starch from just the seed endosperm. As a consequence,the foods made from fine flours, such as bread,are quickly digested and absorbed, and raiseblood sugars rapidly when consumed. Manyrecent studies suggest that carbohydrates thatare digested and absorbed quickly (known ashigh glycemic index foods), increase the risk

of chronic diseases such as type 2 diabetes andcardiovascular disease (Barclay et al. 2008).

Alcohol In contrast to dairy products, cerealgrains, refined sugars, and refined oils, alcoholconsumption represents a relatively minor frac-tion (1 or 2%) of the total energy consumed inwestern diets. The earliest evidence for winedrinking from domesticated vines comes from apottery jar dated ~7000 years BP from northernIran. The fermentation process that produceswine takes place naturally and, without doubt,must have occurred countless times before hu-mans learned to control the process. As grapesreach their peak of ripeness in the fall, theymay swell in size and burst, thereby allowingthe sugars in the juice to be exposed to yeasts

growing on the skins and to produce carbondioxide and ethanol. Because of seasonal fluc-tuations in fruit availability and the limitedliquid storage capacity of hunter-gatherers, it is

likely that fermented fruit drinks, such as wine,would have made an insignificant contributionto total energy in Paleolithic diets.




Salt The total quantity of salt included in thetypical diet of westernized nations amounts

to nearly 10 g/day. About 75% is derived fromsalt added to processed foods by manufactur-ers; 15% comes from discretionary sources (ie,cooking and table salt use), and the remainderoccurs naturally in basic foodstuffs. The system-atic mining, manufacture, and transportationof salt have their origin in the last 10,000 years.The earliest salt use is thought to have takenplace in China about 6000 BC. Paleolithichunter-gatherers living in coastal areas probablydipped food in seawater or used dried salt in amanner similar to nearly all Polynesian socie-ties at the time of European contact. But mostrecently studied inland hunter-gatherers add noor little salt to their food.

Diet and chronic diseasein hunter-gatherers

Dietary fat

In our analysis of hunter-gatherer diets(Cordain et al, 2000), we found that mostgroups exceeded the dietary recommendationto eat 30% or less of energy as fat (Figures 17and 18). In fact, over half of them consumed

amounts not too dissimilar to current westernand Mediterranean dietary intakes. Despitethis, the available evidence suggests that hunt-er-gatherers were generally free of the signs andsymptoms of cardiovascular disease. Researchshows that indigenous populations that derivethe majority of their diet from animal productshave surprisingly low levels of cholesterol andother fats in the blood. Moreover, death certifi-cates, autopsies and clinical studies indicate alow incidence of coronary heart disease amongthe Inuit and other polar populations, consum-ing high intakes of animal foods. However, inwestern diets, higher animal food consumptionis frequently associated with increased mortal-ity from chronic disease. The low incidenceof cardiovascular disease among indigenouspopulations subsisting largely on animal foodsrepresents a paradox.

There is now strong evidence that the absoluteamount of dietary fat is less important in re-ducing the risk for cardiovascular disease thanthe type of fat. Fatty acids that increase blood

cholesterol levels include lauric acid (C12:0),myristic acid (C14:0), palmitic acid (C16:0),and some trans fatty acids (Grundy, 1997),whereas monounsaturated (MUFA) and poly-unsaturated (PUFA) fatty acids reduce choles-terol levels. Stearic acid (C18:0), the major fattyacid in chocolate and lean red meat is neutral.Omega-3 long chain PUFA, found in fish andseafood in general and Australian grass fed beefand lamb, have wide ranging protective capaci-ties including the ability to reduce blood lipids.Consequently, it is possible to consume highfat diets that do not produce an adverse bloodlipid profile or cardiovascular disease.

In their classic study of Greenland Eskimoswho had a near absence of cardiovascular dis-

ease, Bang and Dyerberg (1980) contrasted thedietary and blood lipid profiles of the Eskimosto Danes (Table 3). Despite a much greater ani-mal food intake than the Danes, the Eskimosmaintained a more healthful blood lipid profile.The reduced cholesterol levels in the Eskimosare likely accounted for by the higher dietaryintake of ‘good’ fats. The protein intake of theEskimos was more than twice as high as theDanes, and this pattern (elevated protein at theexpense of carbohydrate) is characteristic of

hunter-gatherers (Cordain et al, 2000a).

Dietary protein

Our analyses of contemporary hunter-gathererdiets show that the average protein intake wasas high as 35% energy (Figure 16). This ismore than twice the level consumed by cur-rent western populations (~15% energy). Highprotein intake in western diets is perceivedto be linked to high calcium excretion in the

urine and faster progression of kidney disease. Yet, paradoxically, high protein diets havebeen shown to improve metabolic control intype 2 diabetes patients. In her classic study of Australian Aborigines temporarily reverting toa hunter-gatherer lifestyle, Kerin O’Dea showedthat animal foods contributed ~65% of the totalenergy, producing an overall macro-nutrientdistribution of 54% protein, 33% carbohydrateand 13% fat energy. Following a 7-week periodliving as hunter-gatherers in their traditional

country in north-western Australia, 10 diabetic,overweight Aborigines experienced either a




great improvement or complete normalizationof all of the major metabolic abnormalitiescharacteristic of diabetes (O’Dea, 1984).

The fossil record indicates pre-agricultural hu-mans generally maintained greater bone massthan modern humans and hence greater bonestrength and resistance to fractures (Bridges,

1995; Ruff et al, 1993). Greater bone strengthhas been attributed to the greater activity pat-terns of pre-agricultural humans, which in turnwould have increased bone loading. It is alsoquite likely that the high fruit and vegetableconsumption in hunter-gatherer diets wouldhave buffered the high acid load and subse-quent high calcium excretion brought aboutby a high protein diet. In western diets, meats,cheeses and cereal grains yield high potential

renal acid loads and hence may promote oste-oporosis (thinning of the bones) by producinga net metabolic acidosis. In contrast, fruits andvegetables yield a net alkaline renal load, andhigh fruit and vegetable diets have been shownto decrease urinary calcium excretion rates.Consequently, in hunter gatherer populationsconsuming high protein diets, a concomitantconsumption of high levels of fruits and vegeta-bles may have countered the effects of a highprotein diet.

Dietary carbohydrate

Our studies also demonstrate that the carbo-hydrate content of hunter-gatherer diets wouldhave ranged from 22 to 40% of total energy(Figure 16). The values within this range areconsiderably lower than average values in west-ern diets or recommended levels (50-60% or

more of total energy). Although current adviceto reduce risk of cardiovascular disease is toreplace saturated fats with carbohydrate (Figure17), there is mounting evidence to indicatethat low fat, high carbohydrate diets may elicitundesirable changes in blood fats, includingreductions in the good cholesterol (HDL) andtriglycerides. Because of these untoward bloodlipid changes, substitution of MUFA for satu-rated fats has been suggested as a more effec-tive strategy than substitution of carbohydratefor saturated fats in order to lower the risk ofcardiovascular disease.

Hunter gatherer diets would not only havecontained less carbohydrate than that typicallyfound in western diets, but there are impor-tant qualitative differences in the types ofcarbohydrates. Western diets are characterizedby carbohydrate foods with a high glycemicindex (e.g. potatoes, bread, processed cerealproducts) whereas the wild plant foods whichwould have been consumed by hunter-gather-ers generally maintain a high fiber content, are

Table 3: Dietary and blood lipid characteristics of Greenland Eskimos and Danes.

Variable Eskimos Danes

Dietary intake:

Protein (% energy) 26.0 11.0

Fat (% energy) 37.0 42.0Carbohydrate (% energy) 37.0 47.0

Saturated fat (% total fat) 22.8 52.7

Monounsaturated fat (% total fat) 57.3 34.6

Polyunsaturated fat (% total fat) 19.2 12.7

n-6 PUFA (g) 5.4 10.0

n-3 PUFA (g) 13.7 2.8

Blood lipid values

Total cholesterol (mmol/liter) 5.33 + 0.78 6.24 + 1.00

Triglycerides (mmol/liter) 0.61 + 0.44 1.32 + 0.53




slowly digested and produce low glycemic andinsulin responses. Observational studies sug-gest that foods with a high glycemic load andlow fiber content increase the risk for type 2diabetes (Barclay et al, 2008).

Other environmental factors

It is likely that hunter-gatherers consumed veryhigh intakes of antioxidants and phytonutrientsand undertook more intense physical exerciseor work patterns (Cordain et al, 1998). Thesecharacteristics would have provided pre-agri-cultural people with further protection fromchronic diseases such as diabetes. Biochemicalstudies of hunter-gatherers have shown highplasma concentrations of folate and vitaminB12. Adequate intake of these two vitamins

along with vitamin B6 reduce homocysteine, animportant risk factor for cardiovascular disease.Hunter-gatherers rarely if ever added salt totheir foods, and studies of salt-free YanomamoIndians have shown these indigenous peopleto maintain low blood pressures that do notincrease with age. Finally, except for certain American Indian societies (starting about 5,000years ago), regular smoking of tobacco was un-known in hunter-gatherers. Any or all of thesedietary and environmental elements wouldhave operated together with the macronutrientcharacteristics of hunter-gather diets to reducesigns and symptoms of the chronic diseasesthat plague western societies.

Conclusions

The diet of our ancestors was characterizedby higher intake of meat and lower intakeof plant foods than is generally recognized.

Modern human beings display physiologicalfeatures which suggest an increasingly carnivo-rous diet during human evolution. Our largebrains increased in size at the expense of thegastronintestinal tract and dictated high intakeof nutrient-rich foods. The high reliance onanimal foods may not have elicited an adverseblood lipid profile because of the benefits ofhigh dietary protein and low level of dietarycarbohydrate. Although fat intake would havebeen similar to or higher than that found in

western diets, there were important qualitativedifferences. The high levels of MUFA and PUFA

and omega-3 fatty acids, would have servedto inhibit the development of cardiovasculardisease. Other dietary characteristics includinghigh intakes of antioxidants, fibre, vitamins andphytochemicals along with a low salt intakemay have operated synergistically with lifestylecharacteristics (more exercise, less stress andno smoking) to further deter the developmentof disease. The modern healthy food pyramidwith its foundation based on cereals rich in car-bohydrate supplemented with small amountsof animal foods (Figure 19) differs greatly fromthe human evolutionary pyramid (Figure 20). Yet it is still possible to consume a healthydiet based on evolutionary principles in whichthe quality of fat, protein and carbohydrateare more critical that their quantity or energy

distribution. Indeed, the insights gained fromPaleolithic nutrition are likely to influence fu-ture dietary guidelines around the world.

Although concerted attempts were made to acknowledge the

source of all images, in some cases this could not be ascertained.

Please contact the author if an infringement has taken place.

Further reading

Barclay A, Petocz P, McMillan-Price J, Flood

VM, Prvan T, Mitchell P, Brand-Miller JC.

Glycemic index, glycemic load and chronicdisease risk – a meta-analysis of observationalstudies. Am J Clin Nutr 2008; 87: 627-37.

Cordain L, Watkins BA & Mann NJ (2001):Fatty acid composition and energy density offoods available to African hominids: evolution-ary implications for human brain development.World Rev. Nutr. Diet. 90, 000-000.

Cordain L, Brand Miller J, Eaton SB, Mann N,

Holt SHA & Speth JD (2000a): Plant-animalsubsistence ratios and macronutrient energyestimations in worldwide hunter-gatherer diets.

Am. J. Clin. Nutr . 71, 682-692.

Cordain L, Brand Miller J, Eaton SB & MannN (2000b): Macronutrient estimations inhunter-gatherer diets. Am. J. Clin. Nutr. 72,1589-1590.

Cordain L, Gotshall RW, Eaton SB & Eaton SB

(1998): Physical activity, energy expenditureand fitness: an evolutionary perspective. Int. J.Sports Med. 19, 328-335.



42 | G G l i

Dahlberg F (1981): Introduction. In: Womanthe Gatherer, ed. F Dahlberg, pp 1-33. NewHaven: Yale University Press.

Eaton SB & Konner M (1985): Paleolithicnutrition. A consideration of its nature and cur-rent implications. N. Engl. J. Med. 312, 283-

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Eaton SB, Konner M & Shostak M (1988a):Stone agers in the fast lane: chronic degenera-tive diseases in evolutionary perspective. Am. J.Med. 84,739-749.

Eaton SB, Shostak M & Konner M (1988b):The Paleolithic Prescription. New York: HarperRow.

Kaplan H & Hill K (1992): Human subsistence

behavior. In: Evolution, Ecology and HumanBehavior, eds, EA Smith & B Winterhalder, pp167-202. Chicago: Aldine.

Kaplan H, Hill K, Lancaster J & Hurtado AM(2000): A theory of human life history evolu-tion: diet, intelligence, and longevity. Evol. Anthropol. 9, 156-185.

Lee RB (1968): What hunters do for a living, orhow to make out on scarce resources. In: Man

the Hunter, eds. RB Lee & I DeVore, pp 30-48.Chicago: Aldine.

Lee RB (1979): The !Kung San: Men, Women,and Work in a Foraging Society. Cambridge:Cambridge University Press.

Mann, N (2000). Dietary lean red meat and hu-man evolution. Eur J Nutr 39: 71-79.

McArthur M (1960): Food consumption anddietary levels of groups of aborigines living on

naturally occurring foods. In: Records of the American-Australian Scientific Expedition to Arnhem Land, ed. CP Mountford, pp 90-135.Melbourne: Melbourne University Press.

Meehan B (1982): Shell Bed to Shell Midden.Canberra: Australian Institute of AboriginalStudies.

Murdock GP (1967): Ethnographic atlas: asummary. Ethnology 6,109-236.

O’Dea K (1984): Marked improvement incarbohydrate and lipid metabolism in diabetic

Australian Aborigines after temporary reversionto traditional lifestyle. Diabetes 33, 596-603.

Richards MP & Hedges RM (2000b): Focus:Gough’s Cave and Sun Hole Cave humanstable isotope values indicate a high animalprotein diet in the British Upper Palaeolithic. J.

Archaeol. Sci. 27, 1-3.

Sinclair HM (1953): The diet of CanadianIndians and Eskimos. Proc. Nutr. Soc. 12, 69-82.

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Speth JD & Spielmann KA (1983): Energysource, proein metabolism, and hunter-gatherer

subsistence strategies. J. Anthropol Archaeol. 2, 1-31.

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