Download What did Adam and Eve eat?

What did Adam
and Eve eat?
An exploration of our ancestral diets
Carrie Ruxton, Freelance Dietitian, Nutrition
Communications – @DrCarrieRuxton
Given the current debates about obesity and non-communicable diseases, one might be tempted
to believe that modern man’s diet went badly wrong in the last few decades. Yet, palaeontologists
suggest that our eating habits went off track much further back and that the answer to today’s
health woes is found in our ancestral hunter-gatherer diets.
While official dietary advice continues to stress the key messages of higher intakes of starchy
carbohydrates, fibre, fruits and vegetables, alongside reductions in fat, saturated fat, salt and sugar, the
Palaeolithic eating pattern may seem surprisingly off-message, particularly for foods such as meat.
This article will explore how nutrition influenced the development of homo sapiens, what our
ancestors may have eaten, and what lessons we can learn today using the modern foods available to us.
The emergence of man
Our long journey, over millions of years, from primate to
contemporary human remains largely a mystery. However, evidence
can be pieced together from the fossil record as well as data
from burial sites, coprolites (prehistoric faeces), tool-making, fire pits
and ancient rubbish dumps.
The fossil record from Africa suggests that the leap from
primate to bipedal hominid occurred around six million years ago,1
with anatomically modern man emerging 200,000 years ago. This
evolutionary sequence was probably triggered by a change in diet
which significantly boosted the availability of high quality protein.2
One theory is that the increased protein consumption, from game,
insects and fish, led to enhanced brain growth which enabled a
rapid acquisition of skills, such as tool-making, language and cultural
expression.3 Others believe that the richer nutritional composition
and higher energy density of meat-rich diets meant that huntergatherers had more free time to spend on social interaction,
18 | CN Focus Vol.6 No.3 October 2014
stimulating brain growth and the acquisition of skills.5 Whether brain
growth or social interaction came first, a key point is that neither
would have occurred without a shift in eating patterns towards a
more nutrient-rich diet.
It is a common misconception that our primate ancestors
were vegetarian but this is not borne out by the evidence. A close
relative of early primates, the tree shrew, was a carnivore feeding
almost entirely on insects and small invertebrates as confirmed by
their dental patterns.5 Later primates increased the plant content
of their diets but remained omnivorous as suggested by fossils
showing the evolution of incisors, canine teeth and premolars, all
of which are designed to facilitate the catching and consumption
of prey. Modern chimpanzees are omnivorous, supplementing
their diets with insects, invertebrates and even other primates.6 In
contrast, the mainly vegetarian gorilla has to practice coprophagy
(the consumption of faeces) in order to derive enough nutrients
from its diet as, in common with all primates, it lacks the necessary
enzymes to digest cellulose.6
Ancestral Diets | Hot Topic
Gut length is another indication that man
developed as an omnivore.7 While natural plant
eaters possess multiple stomachs with a long colon
and caecum to facilitate the digestion of plant
material, the modern human gut is characterised
by a single stomach, medium length intestine and
small colon with a non-functioning appendix.7
The Palaeolithic diet
Modern man is genetically Stone Age and, thus,
adapted to consume the types of foods commonly
found in the late Palaeolithic period.8 These
included game meat, fish, shellfish, fresh fruits and
vegetables, roots, tubers, eggs, and nuts.9,10
According to evidence from contemporary
hunter-gatherer (HG) societies and isotope analysis
of bone collagen from Palaeolithic fossils, these
foods created a diet that was higher in protein and
lower in carbohydrates compared with modern
diets.11 Intakes of long-chain omega-3 fatty acids
and monounsaturated fatty acids were high, while
intakes of linoleic acid and saturated fats were
low,7,12 with trans fats, dairy products and refined
sugars absent.1 Fibre intakes were estimated to
be around 100 g per day, mostly from fruit,
vegetables and uncultivated grains.1 Intakes of
prebiotic fibres, with their associated benefits for
gut health, immune function and metabolic health,
may also have been high,13 as were antioxidants
and phytonutrients (except phytate).
Disadvantages of the diet included low intakes
of calcium and vitamin D. However, the potential
impact on bone health would have been offset by
high physical activity levels and intakes of green
leafy vegetables, as well as low intakes of known
calcium inhibitors, such as salt and phytate.11
Sunlight would have provided the majority of
vitamin D requirements,14 although adaptations to
skin pigmentation were required when early HGs
migrated to Europe.
It is a misconception that Palaeolithic HGs
derived most of their energy from plant foods.
A review of 13 quantitative dietary studies on
modern HGs suggests that animal food provided
two thirds of daily energy intakes with the rest
comprising gathered plant sources.13 Other
evidence for this comes from isotopic analyses
of hominid collagen tissue, low activity levels of
certain enzymes, human gut morphology, human
encephalisation and optimal foraging data.7, 13
Interestingly, the macronutrient profile of the
Palaeolithic diet is different to that recommended
today. Intakes of protein were estimated to be 19-35
per cent energy, while carbohydrates provided
22-40 per cent energy.13 Analysis of the diets of
modern HG societies suggests a huge variation
in carbohydrate content (from 3-50% energy) but
this depends on the environment and the lowest
intakes are seen in tundra dwelling communities,15
whose soils are too fragile to support many plant
foods. Although fat intakes (28-58% energy) would
have been similar to, or higher than, modern
Western diets, the fatty acid composition favoured
a higher omega 3: omega 6 ratio.1
Impact of dietary shifts
Around 10,000 years ago, a sharp rise in
temperatures ended the Ice Age and necessitated
a major dietary shift for early man.16 The loss of
traditional migration routes and campsites, with
their associated flora and fauna, encouraged
HG communities to settle in one area and
begin farming. This is supported by evidence
from mitochondrial DNA samples and isotope
analyses of human fossils which indicates a
gradual, yet overlapping, change from foraging
to agriculturalist diets.17
More recently, further shifts in food choice
and nutrient intakes occurred during the Industrial
Revolution and are still occurring today with
increased globalisation,3 massed food production,
population growth, GMOs and farming practices.
Nowadays, around 70 per cent of daily energy
intake is derived from foods rarely or never
eaten by Palaeolithic HGs, including grains, dairy
products, refined sugars and processed fats.11
According to several commentators, these
fundamental dietary changes have occurred in too
short a timescale for the human genome to
adapt and could explain the unacceptably high
prevalence of certain diseases of affluence, such
as cardiovascular disease, Type 2 diabetes and
cancer.15,18 The suggested mechanisms relate to
the major differences in glycaemic load, fatty
acid composition, macronutrient composition,
fibre content and sodium-potassium ratio between
ancient and modern diets.19
One paradox of traditional HG diets is the
apparent lack of association between high meat
diets and cardiovascular disease.7 Red meat is
often highlighted as a risk factor in (mainly US)
observational studies but modern HG societies,
despite consuming far more meat than would
be recommended in Western countries, have a
far lower incidence of such conditions.13 This
may be because lean red meat contributes
nutritionally significant amounts of nutrients
believed to support heart and immune health,
including LC n3PUFA, iron, zinc, selenium,
thiamin, vitamin B12 and vitamin D.8 Another
consideration is the lower life expectancy of HG
adults.
Studies of contemporary
diets rich in Palaeolithic
foods, including lean red
meat, seafood and fibrous
foods, have revealed
significant and positive
changes to markers of
disease...
Eating like our ancestors
Studies of contemporary diets rich in Palaeolithic
foods, including lean red meat, seafood and
fibrous foods, have revealed significant and
positive changes to markers of disease, such as
waist circumference, C-reactive protein, glycated
haemoglobin, blood pressure, glucose tolerance,
insulin sensitivity and blood lipids.11 This has led
to a renewed interest in incorporating some
of the tenets of the Palaeolithic diet into our
own modern eating patterns. However, despite
these promising results, few intervention trials
have been attempted, perhaps because strict
Palaeolithic diets are difficult to comply with
due to the low cereal content.
CN Focus Vol.6 No.3 October 2014 | 19
Hot Topic | Ancestral Diets
A small ad libitum study19 on nine healthy sedentary
adults compared three days of usual diet with 10
days of a Palaeolithic-type diet comprising lean meat,
fruits, vegetables and nuts, and excluding cereal
grains, dairy and legumes. The results showed a
significant reduction in mean blood pressure, plasma
insulin, total/LDL cholesterol and triglycerides with
all participants displaying similar effects. Another
short-term intervention20 asked 20 participants to
follow a Palaeolithic-type for three weeks but only
14 completed the study and full dietary assessment
was available for six subjects. The metabolic results
for the 14 completers showed a significant fall in
weight, waist circumference and systolic blood
pressure. No control group was recruited which,
along with the large drop-out rate, is a weakness
of this study.
Two publications by the same team have
considered how a Palaeolithic-type diet may
benefit people with Type 2 diabetes. A randomised
controlled trial21 in 13 patients (not on insulin)
compared a typical diabetes diet with a
Palaeolithic-type diet high in lean red meat, fish,
fruits, root vegetables, eggs and nuts. The results
showed significantly lower levels of HbA1c,
triglycerides, diastolic blood pressure, weight
and waist circumference, and higher HDL
cholesterol. A four-day weight dietary record
revealed that the Palaeolithic-type diet was
lower in energy density, carbohydrate, saturated
fat, glycaemic load and calcium, but higher
in unsaturated fatty acids, dietary cholesterol
and several vitamins. In another publication,22
participants’ views were reported, with the
interesting finding that the diets were perceived
to be equally satiating. While more positive
comments were made about the Palaeolithic-type
diet due to participants seeing a benefit to blood
sugar control, participants found adherence to
this diet difficult.
Table One summarises Palaeolithic diets and
their impact on health, and suggests modern
equivalents.
Conclusions
There is clear evidence that man evolved as an
omnivore. Animal products were a significant
part of the diet of early humans and were
inextricably linked with subsequent changes
in brain size and the acquisition of skills. Later
dietary shifts towards a largely cereal-based
diet are believed to have happened too
quickly for our genome to adapt successfully,
increasing the risk of non-communicable
diseases. While the modern version of the
Palaeolithic diet needs further research, there
is growing evidence that a diet of lean red
meat, fish, fruits, root vegetables, eggs and
nuts could offer metabolic benefits and support
weight management.
Table One: Palaeolithic Diets and their Modern Equivalents
References: 1. Eaton SB (2006). The ancestral human diet: what was
it and should it be a paradigm for contemporary nutrition? Proc
Nutr Soc.; 65: 1-6. 2. Babbitt CC, et al (2011). Genomic signatures of
diet-related shifts during human origins. Proc Biol Sci.; 278: 961-9. 3.
Verginelli F, et al. (2009). Nutrigenetics in the light of human
evolution. J Nutrigenet Nutrigenomics.; 2(2): 91-102. 4. Gamble C, et
al (2011). The social brain and the shape of the Palaeolithic. Camb.
Archaeol.; J 21: 115-136. 5. Nowak RM (1999). Walker’s Mammals of
the World, 6th edn; p245. John Hopkins University Press: Baltimore.
6. Fossey D (2000). Gorillas in the Mist. First Mariner Books edition,
Houghton Mifflin Harcourt: Boston. 7. Mann N (2000). Dietary lean
red meat and human evolution. Eur J Nutr.; 39: 71-79. 8. Eaton
SB, Eaton SB 3rd (2000). Paleolithic vs. modern diets--selected
pathophysiological implications. Eur J Clin Nutr.; 39: 67-70.
9. Richards MPR, et al (2005). Isotope evidence for the intensive use
of marine foods by Late Upper Palaeolithic humans. J Hum Evol.; 49:
390-4. 10. Kowalski LM, Bujko J (2012). Evaluation of biological and
clinical potential of paleolithic diet. Rocz Panstw Zakl Hig.; 63: 9-15.
11. Cordain L, et al (2000). Plant-animal subsistence ratios and
macronutrient energy estimations in worldwide hunter-gatherer
diets. Am J Clin Nutr.; 71: 682-92. 12. Cordain L, et al (2002). The
paradoxical nature of hunter-gatherer diets: meat-based, yet nonatherogenic. Eur J Clin Nutr.; 56: S42-52. 13. Leach JD, Sobolik KD
(2010). High dietary intake of prebiotic inulin-type fructans in the
prehistoric Chihuahuan Desert. Br J Nutr.; 103: 1558-1561. 14. Jew S,
et al (2009). Evolution of the human diet: linking our ancestral
diet to modern functional foods as a means of chronic disease
prevention. J Med Food.; 12: 925-34. 15. Strohle A, Hahn A
(2011). Diets of modern hunter-gatherers vary substantially in
their carbohydrate content depending on ecoenvironments:
results from an ethnographic analysis. Nutr Res.; 31: 429-35.
16. Dobrovolskaya MV (2005). Upper palaeolithic and late stone age
human diet. J Physiol Anthropol Appl Human Sci.; 24: 433-8.
17. Bollongino R, et al (2013). 2000 years of parallel societies in Stone
Age Central Europe. Science; 342: 479-81. 18. Cordain L, et al (2005).
Origins and evolution of the Western diet: health implications for
the 21st century. Am J Clin Nutr.; 81: 341-54. 19. Frassetto LA, et al
(2009). Metabolic and physiologic improvements from consuming
a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr.; 63: 947-955.
20. Österdahl MT, et al (2007). Effects of a short-term intervention
with a paleolithic diet in healthy volunteers. Eur J Clin Nutr.; 62:
682-685. 21. Jönsson T, et al (2009). Beneficial effects of a Paleolithic
diet on cardiovascular risk factors in type 2 diabetes: a randomized
cross-over pilot study. Cardiovasc Diabetol.; 8: 1-14. 22. Jönsson T,
et al (2013). Subjective satiety and other experiences of a Paleolithic
diet compared to a diabetes diet in patients with type 2 diabetes.
Nutr J.; 12:105.
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Palaeolithic diets
Nutrient/health impact
Modern equivalents
High intakes of game meat
High intakes of MUFA, PUFA, lower SFA. Choose lean red meat and game, remove
High intakes of protein
visible fat and cook without extra fat, or
use olive oil
Low intakes of processed
carbohydrates and modern
grains
Lower carbohydrate content and lower
GL than modern diets. More dietary
variety from gathered grains
Include a wider range of wholegrains in
the diet e.g. rye, spelt, barley, flax, teff
(ancient grain)
Use of honey and fruits to
sweeten
Reduced added sugar consumption,
lower GI
Honey and fruits can still be used to
sweeten
Foraged marine foods
High intakes of n3PUFA and vitamin D
Consume fish twice a week, including
one portion of oily fish. Consume
shellfish and molluscs
Wide variety of foraged plant
foods
High intakes of fibre and PUFA
Snack on nuts and seeds. Choose a wider
variety of vegetables
Key: GI – glycaemic index; GL – glycaemic load; MUFA – monounsaturated fatty acids; n3 – omega-3; PUFA – polyunsaturated fatty acids;
SFA – saturated fatty acids.
Acknowledgment
Funding for this research review was provided by the Meat Advisory Panel (MAP) which is a
group of experts who provide independent and objective information about red meat and its
role as part of a healthy, balanced diet. MAP is supported by an unrestricted educational grant
from EBLEX and BPEX, divisions of the Agriculture and Horticulture Development Board (AHDB).
For more information, see www.meatandhealth.com