Miller Mann Cordain Paleolithic Nutrion

8/8/2019 Miller Mann Cordain Paleolithic Nutrion

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Paleolithic

nutrition:whatdid our ancestors

eat?Janette Brand MillerNeil Mann

Loren Cordain


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Paleolithic nutrition is the study odiets consumed by our early stone

age ancestors, members o our spe-cies who lived rom 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 liestyle (Figure 2). Paleolithicdiets are a subject o interest or various reasons.Apart rom the intrinsic value o 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 or the greater part o one mil-lion years o human evolution is the ideal diet.Conversely, they believe that modern illnessessuch as type 2 diabetes and coronary heart dis-ease are a consequence o 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.


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Paleolithic nutrition: what did our ancestors eat? |31

Climate dictates food sources

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

ripe ruits, leaves and berries rom the tropicalorests (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 o moist Aricanwoodland into much drier open savanna. Asthe grasslands expanded, the tree cover shrankand one or more species o orest dwellingchimpanzee evolved into bipedal hominids(Figure 6). Homo habilis who lived 2 million

years BP supplemented a largely vegetarian dietwith meat let over rom 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 or the larger andlarger brain o our species, Homo sapiens sapiens(the phrase man the hunter originated withthis idea)(Figure 7 and 8).

As one Ice Age ollowed another, hunting and

shing became a dominant way o lie in bothwarm and cold environments. During Ice Ages,large amounts o water become locked intothe polar ice caps, making the whole planetdrier because less water alls as rain and snow.Plant growth slows, rainorests 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 o large game. Indeed,over winter they subsisted primarily on game.One large mammoth kill would have nourisheda amily group o 50 individuals or at least3 months. Similarly, Cro-Magnon man whoreplaced the Neanderthals about 35,000 yearsago, lived through the coldest o the Ice Ageson a high meat diet. The Hall o Bulls in theamous Lascaux Caves in southern France is atestament to the importance o animals to thepeople who lived 17,000 years ago (Figure 9).

Similarly, we know that the ancestors o theAborigines who inhabited Australia 40-50,000years ago led a hunting and shellsh gathering

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

During the early and mid 20th century, anthro-pologists studied the planets ew remaininghunter-gatherer societies. To their surprise,they ound them generally ree o the signsand symptoms o the so-called diseases ocivilization. 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 o wild and unculti-vated oods making up humanitys native diet.Consequently, the characterization and descrip-tion o hunter-gatherer diets has importantimplications in designing therapeutic diets thatreduce the risk or chronic diseases in modern,western cultures.

These ethnographic and anthropological stud-

ies tell us that there was no single, uniormdiet which typied the nutritional patternso all pre-agricultural humans. Humans weremasters o fexibility, with the ability to live in arain orest or near the polar ice caps. Yet, basedupon limited inormation, many anthropolo-gists incorrectly concluded that the universalpattern o subsistence was one in which plantoods contributed the majority o ood energy.However, more recent and comprehensiveethnographic compilations (Cordain et al,2000a) as well as quantitative dietary analysesin oraging populations, have been unable toconrm the conclusions o these earlier studies.In act, the later studies demonstrated that ani-mal oods, rather than plant oods, comprisedthe majority o energy in the typical hunter-gatherer diet.

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


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32|Genes to Galaxies

Inclusion of more animal food in the

diet allowed brain to enlarge

How? Humans expend 20-25% of

RMR 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 36:199-221

Evidence of Complex Big Game

Hunting in Homo Sapiens

Anatomically modernH. sapiens appear(~100,000 yrs ago)

A spear point wasfound lodged in the

vertebra of a giant

buffalo at Klasies RiverCave, 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

Frequency

% 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

Frequency

% 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 evidencecomes from observations of

early ethnographers who

studied worlds remnant

hunter-gatherers

Figure 7

Figure 9

Figure 11

Figure 8

Figure 10

Figure 12


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and more importantly, about one third o thesaturated at, the kind mostly clearly linkedto adverse outcomes. Thus, a high meat diet,regardless o its at quantity and type, is gener-ally perceived to be unhealthy and to promotecardiovascular and other chronic diseases.Yet Australian red meat derived rom grazinganimals is generally lean, low in saturated atand contains signicant amounts o healthylong chain omega-3 ats. Ourresearch providesevidence that the animal oods that dominatedhunter-gatherer diets were also low in saturatedat and high in good ats. This nutritional pat-tern would not have promoted atherosclerosis(hardening o 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 o 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 o evidencesuggesting that contemporary hunter-gathererpeoples consumed more gathered plants thanhunted animal ood (Lee, 1968) (Figure 10).For example, Lees studies o the Arican !Kungpeople demonstrated that gathered plant oodscomprised 67% o their average daily energyintake while hunted animal oods encompassedthe remaining third. Lee urther compiled datarom 58 hunter-gatherer societies who werelisted in the Ethnographic Atlas (Murdock,1967), showing that hunted animal ood madeup only 35 per cent o ood intake, irrespective

o latitude.

Over the next 30 or so years, Richard Leesanalysis was widely misinterpreted to meanthat gathered plant oods typically providedthe major ood energy in worldwide hunter-gatherer diets, while hunted animal oods madeup the balance. But this general perceptionis incorrect becausefshed animal oods mustbe summed with hunted animal oods in theanalysis o the ethnographic data to more cor-

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

by plants versus animal oods). Our analysis(Figures 11-14) o Grays Ethnographic Atlasdata (Gray, 1999) showed that the dominantoods in most hunter-gatherer diets were de-rived rom animal ood sources. We ound thatnearly 3 in 4 o the worlds hunter gathererpopulations obtained at least hal o their oodenergy rom hunted and shed animal oods,whereas ewer than 1 in 7 obtained more thanhal their calories rom gathered plant oods.Not a single hunter-gatherer society was com-pletely vegetarian. The statistical mean amongall 229 hunter-gatherer societies in Grays atlasindicated that 68% o calories came rom ani-mal oods and 32% rom gathered plant oods(Figure 15).

Quantitative studies ofhunter gatherer diets

The major limitation o ethnographic data isthat much o the inormation is subjective innature. Murdocks scoring or the ve basicsubsistence economies in the Ethnographic Atlaswere approximations, rather than preciselymeasured ood intake data. Fortunately, moreexact, quantitative dietary studies were car-ried out on a small number o hunter-gatherersocieties. Table 1 lists these studies and showsthe plant to animal subsistence ratios. Themean score or animal ood subsistence is 65%,while that or plant ood subsistence is 35%.These values are similar to our analysis o theentire (n = 229) sample o hunter-gatherersocieties (Figure 15). I we exclude the twopolar hunter-gatherer populations (who haveno choice but to eat animal ood because othe inaccessibility o plant oods) rom Table 1,

the mean score or animal subsistence is ~60%and that or plant ood 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 o ossil bones can tell us moreinormation about the type o oods that ourancestors ate. Isotopic analysis o the skeletonso Neanderthals (Richards et al, 2000a) andPaleolithic humans (Richards et al, 2000b)


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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

Freque

ncy

% 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 02

6

23

30

35

45

42

46

0

5

10

15

20

25

30

35

40

45

50

Frequ

ency

% 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 MacronutrientsHunter 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


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suggests that the dominance o animal oodsin 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 o hominids living in Europe during

the Paleolithic were indistinguishable rom thato carnivores such as arctic oxes and wolves.Indeed, hominids may have experienced genet-ic adaptations to animal-based diets early on intheir evolution, analogous to those o obligatecarnivores such as cats (elines).

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

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

are essential cellular lipids that are ound onlyin animal oods. The implication is that by eat-ing abundant pre-ormed sources o these attyacids, 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 rom its precursor amino acids.Vegetarian diets are known to result in lowerblood concentrations o taurine. This impliesthat the need to synthesize taurine may havebeen unnecessary because dietary sources opre-ormed taurine had relaxed the selectivepressure to maintain the metabolic machinery.

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

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

a populations average IQ. (Incidentally, iodinedeciency is rising sharply in Australia becausedairy manuacturers 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


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to shun very small animals or at-depleted ani-mals because o their excessive protein content.Historical accounts documented the adversehealth eects that occurred when people wereorced to rely solely on at-depleted, wild ani-

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

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

important actor in shaping their ood procure-ment strategies. Lean meat, thereore, couldnot be eaten in unlimited quantities, but ratherhad to be accompanied by sucient at, or bycarbohydrate derived rom plant ood sources.

This simple physiological act could explainour innate drive to consume atty and sweetoods.

Modern vs traditionalfood choices

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

and animal oods. With the initial domestica-tion o plants and animals, the original nutrientcharacteristics o oods changed, subtly at rst

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


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

Today we eat many types o ood that wereabsent rom the diet o Paleolithic people.

Dairy products, cereals, rened sugars, renedvegetable oils, and alcohol make up over 70%o the total daily energy consumed by people indeveloped nations (Figure 16). But these typeso oods would have contributed little or noneo the energy in the typical pre-agricultural hu-man diet. Additionally, mixtures o oods thatmake up much o our present diet(eg, cookies,cake, breakast cereals, bagels,rolls, muns,crackers, chips, snack oods, pizza, sot drinks,

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

Dairy foods Humans, like all mammals, wouldhave consumed the milk o their own speciesduring inancy. However, aterweaning, theconsumption o milk and milk products oothermammals would have been minimal.Sheep, goats and cows were not domesticateduntil ~10,000 years ago and direct evidence odairying datesto only ~6000 years ago. Most o

the worlds population still does not consumemilk beyond inancy. It should not be surpris-ing thereore to learn that more than 80% ohumans do not have the capacity to hydrolyselactose, the carbohydrate in milk, ater earlychildhood. However, European Caucasians andtheir descendents in America and Australia,who have been exposed to dairying or severalthousand years, can generally digest lactosewell throughout lie.

Cereals Wild cereal grains are usually small,dicult to harvest,and virtuallyindigestiblewithout processing (grinding) and cooking. Forthis reason,Paleolithic people ate little o them.Grinding tools in the ossil recordrepresents areliable indication o when and where cultures

began to include cereal grains in their diet.

Ground stone mortars, bowls, and cup holesrst appearedrom 40,000 years ago to 12,000years ago. Domestication o emmerand einkornwheat heraldedthe beginnings o early agricul-ture in southeastern Turkey about 10,000 yearsago. There was thereore little or no previous

evolutionary experienceor cereal grain con-sumption throughout human evolution. Again,it should not be surprising to learn that manypeople are allergic to the gluten protein oundin wheat, rye and barley. Known as celiacdisease, it causes the bodys immune system toattack itsel and aects more than one in every133 people.

Today, most cereals consumed inthe west-ern diet are highly processed rened grains.Precedingthe Industrial Revolution, all cerealswere ground with theuse o stone milling tools,and unless the four was sieved,it containedthe entire contents o the cereal grain, includ-ingthe germ, bran, and endosperm. Withthe invention o mechanizedsteel roller mills

and automated siting devices in the latter

part o the 19th century, the nutritional andphysiological characteristicso milled grainchanged, becoming virtually pure starch romjust the seed endosperm. As a consequence,the oods made rom ne fours, 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 oods), increase the risk

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

Alcohol In contrast to dairy products, cerealgrains, rened sugars,and rened oils, alcoholconsumption representsa relatively minor rac-tion (1 or 2%) o the total energy consumed inwestern diets. The earliest evidence or winedrinking rom domesticated vinescomes rom apottery jar dated ~7000 years BP rom northernIran. The ermentation process that produceswine takes place naturallyand, without doubt,must have occurred countless times beorehu-mans learned to control the process. As grapesreach theirpeak o ripeness in the all, 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 o seasonal fuc-tuations in ruit availabilityand the limitedliquid storage capacity o hunter-gatherers,it is

likely that ermented ruit drinks, such as wine,wouldhave made an insignicant contributionto totalenergy in Paleolithic diets.


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

to nearly 10 g/day. About 75% is derived romsalt added to processedoods by manuactur-ers; 15% comes rom discretionary sources(ie,cooking and table salt use), and the remainderoccursnaturally in basic oodstus. The system-atic mining, manuacture, and transportationo salthave their origin in the last 10,000 years.The earliest saltuse is thought to have takenplace in China about 6000 BC. Paleolithichunter-gatherers living in coastal areasprobablydipped ood in seawater or used dried saltin amanner similar to nearly all Polynesian socie-ties at thetime o European contact. But mostrecentlystudied inland hunter-gatherers add noor little salt to theirood.

Diet and chronic diseasein hunter-gatherers

Dietary fat

In our analysis o hunter-gatherer diets(Cordain et al, 2000), we ound that mostgroups exceeded the dietary recommendationto eat 30% or less o energy as at (Figures 17and 18). In act, over hal o them consumed

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

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

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

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

ease, Bang and Dyerberg (1980) contrasted thedietary and blood lipid proles o the Eskimosto Danes (Table 3). Despite a much greater ani-mal ood intake than the Danes, the Eskimosmaintained a more healthul blood lipid prole.The reduced cholesterol levels in the Eskimosare likely accounted or by the higher dietaryintake o good ats. The protein intake o theEskimos was more than twice as high as theDanes, and this pattern (elevated protein at theexpense o carbohydrate) is characteristic o

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

Dietary protein

Our analyses o 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 aster progression o kidney disease.Yet, paradoxically, high protein diets havebeen shown to improve metabolic control intype 2 diabetes patients. In her classic study oAustralian Aborigines temporarily reverting toa hunter-gatherer liestyle, Kerin ODea showedthat animal oods contributed ~65% o the totalenergy, producing an overall macro-nutrientdistribution o 54% protein, 33% carbohydrateand 13% at energy. Following a 7-week periodliving as hunter-gatherers in their traditional

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


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great improvement or complete normalizationo all o the major metabolic abnormalitiescharacteristic o diabetes (ODea, 1984).

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

1995; Ruet al, 1993). Greater bone strengthhas been attributed to the greater activity pat-terns o pre-agricultural humans, which in turnwould have increased bone loading. It is alsoquite likely that the high ruit and vegetableconsumption in hunter-gatherer diets wouldhave buered 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 o the bones) by producinga net metabolic acidosis. In contrast, ruits andvegetables yield a net alkaline renal load, andhigh ruit and vegetable diets have been shownto decrease urinary calcium excretion rates.Consequently, in hunter gatherer populationsconsuming high protein diets, a concomitantconsumption o high levels o ruits and vegeta-bles may have countered the eects o a highprotein diet.

Dietary carbohydrate

Our studies also demonstrate that the carbo-hydrate content o hunter-gatherer diets wouldhave ranged rom 22 to 40% o 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 o total energy). Although current adviceto reduce risk o cardiovascular disease is toreplace saturated ats with carbohydrate (Figure17), there is mounting evidence to indicatethat low at, high carbohydrate diets may elicitundesirable changes in blood ats, includingreductions in the good cholesterol (HDL) andtriglycerides. Because o these untoward bloodlipid changes, substitution o MUFA or satu-rated ats has been suggested as a more eec-tive strategy than substitution o carbohydrateor saturated ats in order to lower the risk ocardiovascular disease.

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


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

Other environmental factors

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

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

Conclusions

The diet o our ancestors was characterizedby higher intake o meat and lower intakeo plant oods than is generally recognized.

Modern human beings display physiologicaleatures which suggest an increasingly carnivo-rous diet during human evolution. Our largebrains increased in size at the expense o thegastronintestinal tract and dictated high intakeo nutrient-rich oods. The high reliance onanimal oods may not have elicited an adverseblood lipid prole because o the benets ohigh dietary protein and low level o dietarycarbohydrate. Although at intake would havebeen similar to or higher than that ound in

western diets, there were important qualitativedierences. The high levels o MUFA and PUFA

and omega-3 atty acids, would have servedto inhibit the development o cardiovasculardisease. Other dietary characteristics includinghigh intakes o antioxidants, bre, vitamins andphytochemicals along with a low salt intakemay have operated synergistically with liestylecharacteristics (more exercise, less stress andno smoking) to urther deter the developmento disease. The modern healthy ood pyramidwith its oundation based on cereals rich in car-bohydrate supplemented with small amountso animal oods (Figure 19) diers greatly romthe human evolutionary pyramid (Figure 20).Yet it is still possible to consume a healthydiet based on evolutionary principles in whichthe quality o at, protein and carbohydrateare more critical that their quantity or energy

distribution. Indeed, the insights gained romPaleolithic nutrition are likely to infuence u-ture dietary guidelines around the world.

Although concerted attempts were made to acknowledge the

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

Please contact the author i an inringement 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 o observationalstudies. Am J Clin Nutr 2008; 87: 627-37.

Cordain L, Watkins BA & Mann NJ (2001):Fatty acid composition and energy density ooods available to Arican hominids: evolution-ary implications or 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 tness: an evolutionary perspective. Int. J.Sports Med. 19, 328-335.


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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 o its nature and cur-rent implications. N. Engl. J. Med. 312, 283-

289.

Eaton SB, Konner M & Shostak M (1988a):Stone agers in the ast 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 o human lie history evolu-tion: diet, intelligence, and longevity. Evol.Anthropol. 9, 156-185.

Lee RB (1968): What hunters do or 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 o groups o aborigines living on

naturally occurring oods. In: Records o theAmerican-Australian Scientic Expedition toArnhem Land, ed. CP Mountord, pp 90-135.Melbourne: Melbourne University Press.

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

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

ODea K (1984): Marked improvement incarbohydrate and lipid metabolism in diabetic

Australian Aborigines ater temporary reversionto traditional liestyle. Diabetes 33, 596-603.

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

Archaeol Sci27, 1-3.

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

Speth JD (1989): Early hominid hunting andscavenging: the role o meat as an energysource. J. Hum. Evol. 18, 329-343.

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

subsistence strategies.J Anthropol Archaeol2,1-31.

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