Our Ancestral Diet

1
Our Ancestral Diet

• Is Paleolithic Nutrition
• Relevant Today?

2
Going Back in Time

• Why bother?
• How do we know what ancient humans ate?
• How has our diet changed?
• Can our ancestors diet inform the way we eat
  today?

3
Why Bother?

• Agriculture developed rather recently, in
  evolutionary time.
• Now we have diseases of civilization or
  affluence, diseases unknown before agriculture.

4
Meat-Eating from an Ecological Perspective

• Plants are relatively indigestible cant move,
  heavily defended.
• Animals are plant nutrients packaged in
  digestible form.

5
How Can We Know What Ancient Humans Ate?

• Comparison with closest ape relatives.
• Archeological record.
• Comparison with contemporary and historic
  hunter-gatherers.

6
Comparison with Apes

• Great apes take most of their nutrition from
  plant foods
• Gorillas, orangutans 99
• Chimpanzees mostly ripe fruit, but some
  termites and ants

7
Comparative Morphology

• Compared to other apes, humans have a longer
  small intestine and smaller colon suggests
  nutritionally dense and highly digestible diet.

8
Energy and the Brain in Apes

• Having a big brain, and body, takes lots of
  energy.
• Humans put 3 times as much energy into their
  brain as the great apes.
• Meat-eating likely explanation.

9
Conclusions from Comparisons

• Humans are adapted to a diet containing a
  substantial amount of animal source proteins.
• Humans are able to utilize a variety of energy
  sources, both plant and animal.

10
Evidence of Ancient Diets

• Fossil record morphological evidence.
• Archaeological record evidence of technology.
• Paleoanthropological record cultural/behavioral
  evidence.

11
What Did the Dietary Shift to More Animal Foods
Mean?

• Meat provides protein, vitamins, minerals, fatty
  acids essential nutrients.
• Plants can be used as energy sources, with
  nutrient requirements met.
• Animal source foods provided nutrients to
  detoxify low quality plant foods.

12
Morphological Changes

• Changes in skull and jaw shape increasing brain
  size, decreasing jaw and musculature.
• Homo sapiens (200,000 ya) big brain linked to
  meat consumption.
• Some researchers feel fruit eating could explain
  changes.

13
Material Culture

• From ancient humans, only stone tools survive,
  and these are very generalized, but often found
  with animal bones.
• From more recent humans, many specialized tools
  were clearly used for hunting and butchering.
• Because plant parts do not survive, the material
  culture record may be biased.

14
Cooking A biological trait?

• No known human populations have lived without
  cooked food.
• Cooking began at least 250,000 ya, but perhaps
  500,000 or more ya.
• Tenderizes meat, makes plants more digestible.
• Required to social cooperation, ? influenced
  gender roles evolutionary psychology.

15
Hunter-Gatherers

• All hunter-gatherer societies utilize animal
  source foods.
• Generally, energy contributions of animal foods
  are gt50.
• Estimates from this group are not without
  problems.

16
Moving Towards Agriculture

• Large herbivores disappearing human population
  at carrying capacity.
• Homo sapiens broadened the food resources
  utilized the broad spectrum revolution.
• Wild cereal grains and small grass seeds gain
  importance in the diet.

17
Neolithic Agricultural Revolution

• Dependence on cereal grains.
• Domestication of animals, but not everyone had
  access.
• Insoluble (grain) fiber replaced soluble (fruit
  and vegetable) fiber.
• Salt and sugar cane production.
• Consequences Population grows, height and health
  suffer

18
Agriculture after the Industrial Revolution

• Roller-milling reduced fiber of cereal grains.
• Omega-6 fatty acids become prominent -- Cold
  pressing and grain-fed animals.
• Beef pricing rewards maximum fat deposition.
• Commercial food production salt, white flour,
  sugar, trans- fatty acids.
• Unprecedented availability of calories.

19
Paleolithic vs. Modern Diet Major Contrasts

• Probably more protein in Paleolithic
• Fat profile different (long chain polyunsaturated
  fatty acids vs. serum cholesterol raising
  saturated fat)
• Omega 6 Omega 3 essential fatty acid ratio
  (equal vs. 101 ) fish, eggs, grass fed animals
  vs. processed oils

20
Major Contrasts continued

• High fiber/ Low fiber
• Fruit vegetable carbohydrates/ cereal grains,
  sugar and milk
• Low glycemic load/ high
• High nutrient levels/ low
• High levels of phytochemicals/ low
• Net base producing/ acid producing

21
Implications Meat and Heart Health

• High protein plus low carbohydrates equals lower
  blood lipid levels.
• Higher proportion of mono- and polyunsaturated
  fats.
• High intake of antioxidants, fiber, vitamins.
• Low salt intake.
• Lots of exercise.

22
Implications Sodium and Potassium

• Sodium-potassium ratio reversal
• Addition of manufactured salt
• Displacement of potassium rich foods with cereals
  and milk
• Contributes to hypertension, stroke, kidney
  stones, osteoporosis, exercise-induced asthma,
  and more.

23
Implications Insulin Resistance

• Insulin resistance is a response to a high
  protein/low carbohydrate diet, with periodic
  starvation.
• Kept glucose available for brain, fetus, and
  mammary glands.
• In early agricultural times, carbohydrates were
  complex with low glycemic index thats changed
  now.

24
Diet Recommendations from our Ancestors

• Eat real food.
• Eat more fruits and vegetables as your
  carbohydrate sources-- 8 or more servings per day
  (!)
• Eat lean protein best sources are wild game, or
  grass fed.
• Eat monounsaturated fats from nuts and olive oil
• Cravings for calorie dense foods are our legacy
  eat adequate protein and fat for satiety.
• Avoid being breaditarian.
• Drink water.