What evolution tells us about modern lives and diets

4/8/2016
Paleofantasy: What evolution tells
us about modern lives and diets
11th Annual Building Healthy
Lifestyles Conference
Marlene Zuk
Ecology, Evolution and Behavior
University of Minnesota
Glamour magazine: The cavewoman’s
guide to good health


From Well, NYT blog on health

“It’s worked for women
for hundreds of
thousands of years, and
it’ll work for you, too.”
“Biologically, we modern
Homo sapiens are a lot
like our cavewoman
ancestors:We’re animals.
Primates, in fact. And we
have many primal needs
that get ignored.That’s
why the prescription for
good health may be as
simple as asking, What
would a cavewoman do?”
“Probably goes all the
way back to caveman
days—women out
gathering berries,
sweeping up the place,
generally always on the
run. Cave Mr. Man out
risking his neck, hunting
a sabre tooth tiger or
maybe a wooly
mammoth, dragging the
thing home, and then
collapsing in a heap on
the couch with a beer. I
get it—makes sense.”
New age cavemen?
Are we mismatched to modern life?
Some people want to
emulate long-ago life
 Such a life seems more
natural, or healthier
 Alternatively, some
hold that we can’t shed
our past – whether we
want to or not

Tony Cenicola/The New York Times
http://www.chester.ac.uk/~sjlewis/DM/
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Diets and what’s natural
Food is the place
where people wonder
most about how
evolutionary history
affects their health
 We have many novel
foods
 We also have many
diet-related ailments

Turning to evolution for answers

Makes sense to many
that we should eat
what we were “meant”
to eat
◦ What is that?
◦ What did we eat in the
past?
◦ (How) do we know?
http://wholehealthsource.blogspot.com/2010_11_01_archive.html
http://face-slim.com/fitness/start-eating-natural-diet-tips/
http://slism.com/diet/5best-natural-diet-supplements.html
Or should we go back even further?



“Chimp Food was created to
mimic the healthy diet of our
closest living relatives,
Chimpanzees, who are almost
99% like us, however they live
virtually disease free.”
“Just imagine, NO Obesity,
Heart attacks, Strokes,
Cancer, Diabetes, Alzheimer's,
Parkinson's, Arthritis,
Headaches, ADD, Depression
and thousands of other
diseases.”
“The biggest difference
between Humans and Chimps
is that they are healthy... and
we are not! Our digestive
systems are nearly the same,
so it only makes sense, we
should be eating like them –
Fruits, Berries,Veggies, Nuts
and Seeds.”
http://www.harvestlandbrand.com/
Humans changed quickly
Agriculture only
about 10,000 years
old
 Many diseases and
problems apparently
arose recently



Diabetes, obesity
So would we be
better off living like
we did back then?
http://www.ruralwellbeing.org.uk/images/caveman_modernman.gif
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Living things are all made up of
tradeoffs and compromises
Adaptation often
looks perfect
 But organisms always
have to do multiple
things with limited
resources
Evolution just has to
be good enough
We have never been
in perfect harmony
with our
environment
 Did we feel uneasy
when we began
hunting instead of
scavenging?
 Maybe we should
long to be aquatic
Evolution and progress
Evolution and progress


◦ The insect has to
maintain immunity as
well as camouflage

When was that utopia, again?
Those cartoons
almost never show
women
 Assume straight line
evolution, with one
form replaced by the
(better) one
afterwards

Evolution and progress
What about average lifespan?
Most of all, imply that
evolution has a goal
 But of course,
evolution – and
organisms – aren’t
trying to get
anywhere
 Humans aren’t at the
pinnacle


designboom.com/project/march-of-progress/
People often argue that evolution acted
very differently a long time ago, because
no one lived to be very old
 Average lifespan said to be less than 40
for some ancient populations
 Therefore, no opportunity to experience
the world as a 40, 50, or 60 year old
existed until very recently
evolution.berkeley.edu/evosite/misconceps/IBladder.shtml
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4/8/2016
A hypothetical population of 100
people . . .
Half (50) die at age 5
clipproject.info/free-clipart-gallery
hasslefreeclipart.com
The remainder live into adulthood
They all reach age 60
Then, 20 more die
The remainder reach age 75
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4/8/2016
And then all succumb
What’s the average age at death?
50 times age 5
20 times age 60
 30 times age 75
 Total


= 250
= 1200
= 2250
= 3700
Divide by 100, and the average age at death
= 37, even though many lived well past that
age
 Means that older individuals still existed in
ancient times (cancer)

Stuck in the Stone Age, with old
genes?





Not really
Our genes came from
our ancestors
Who got them from
their ancestors
Etc.
No one period in time
is most significant
What does it mean to have Stone
Age genes?




Some of our genes are
identical to those in
bacteria, others to
worms or chickens
Genetic similarity is
not the whole story
We share ~ 1/3 of our
genes with daffodils
Just counting up the
sequences isn’t
necessarily helpful
http://www.dailymail.co.uk/sciencetech/article-1212692/Our-stone-Age-ancestorswore-bright-garish-clothes.html
Human diet-related genes can
evolve rapidly: lactase persistence
The poster child for
recent human
evolution!
 Other mammals
cannot digest lactose
(milk sugar) after
weaning

◦ Lose lactase

Some humans can
scientificamerican.com/article.cfm?id=what-makes-us-human
science.howstuffworks.com/life/botany/daffodil-info.htm
Rapid evolution in humans: cattle
herding & gene-culture coevolution
People began herding
cattle for meat and
hides
 Being able to digest
milk advantageous

◦ Nutrition, fluid
Stephen Anderson/Modern and Mobile
People with lactase
persistence became
more prevalent
 This selected for
more cattle herding

www.touregypt.net/featurestories/cattle.htm
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4/8/2016
Rapid evolution in humans: cattle herding &
gene-culture coevolution
Rapid evolution in humans: lactase
persistence today
Selection doesn’t
have to be that
strong to change
population
 Can happen quickly

Worldwide, about
35% of people have
lactase persistence
 Genetic change in
people from
northern Europe,
parts of Africa
 The actual gene is
different, but effect
same

◦ A 3% increase in the
reproductive fitness of
those with lactase
persistence could
make such a gene
widespread after only
300 – 350 generations
Rapid evolution in humans: what
about other foods?

In 2010, Anna
Revedin & colleagues
discovered starchy
grains on grinding
stones

People from areas
where starch is a
staple food have more
copies of amylase gene
◦ Used to break down
starches
◦ 30,000 years old

Rapid evolution in humans: what
about other foods?

Ancestral humans
were making “a kind
of pita”
Neandertals, early
humans may have
consumed more grains
than previously
thought
http://news.sciencemag.org/paleontology/2010/10/cavemens-complex-kitchen
Why is this a big deal?
Even “unprocessed” foods unlike
their ancestral state
Early humans often
assumed to rely
mainly on meat
 Starches vilified in
many diets
 Grains viewed as
linked to obesity,
other disorders,
because insufficient
time to adapt

http://thehistorykitchen.com/2011/06/03/the-history-of-doughnuts/
http://www.geneticliteracyproject.org/
2014/06/19/how-your-food-would-look
-if-not-genetically-modified-over-millennia/#.U6NZpbHii8C
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So what did early people eat?
This is not to embrace the “SAD”
(Standard American Diet)
http://www.nutrientrich.com/the-standard-american-diet
http://www.healthy-living.org/html/children_s_health_risks.html
Ample evidence that
eating mainly calorierich, nutrient-poor
foods is bad for us
 But that doesn’t
mean we can only
thrive on what
people ate long ago

Lots of different things
Depends on exactly
when, where we are
talking about
 And our information is
woefully incomplete


◦ Modern foraging
peoples are not a great
model
◦ (even if we knew what
that was)
http://www.dailymail.co.uk/sciencetech/article-2131933/Passmammoth-rib-Eating-meat-helped-early-man-spread-quickly
-profoundly-affected-evolution.html
Was it the switch to agriculture?
Agriculture changes
many aspects of
human life beyond
diet

Industrial Revolution
◦ Changed our diets
◦ Changed how we
spend our time
◦ Changed our health
◦ Allows higher birth
rate, larger population
◦ New diseases
◦ Social stratification
http://marchand.historyproject.ucdavis.edu/2013/03/
http://www.verticalbridge.ca/blog
Are humans still evolving?
Are humans still evolving?
Some, including some
scientists, say no
 Western medical
care, contraception
have changed us


http://webs.bcp.org/sites/vcleary/ModernWorldHistoryTextbook/
IndustrialRevolution/IREffects.html

Maybe – but many big events in
human history
But many people do
not have access to
medical care,
contraception
◦ And disease still a real
threat
◦ Many people survive
today who would have
died not so long ago
◦ We control our
reproduction

Besides, remember
that people are not
the end point of
evolution
http://openclipart.org
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4/8/2016
Current evolution: the Framingham
Study
The real question
“The question ‘Are
humans still evolving’
should be rephrased as,
‘Do all people have the
same number of
children?’”
 Differential genetic
representation means
evolution

Mary Pavelka, Univ. of Calgary
Current evolution: the Framingham
Study
Data can also be
used to see which
genes likely to be
represented in future
generations
 Who has more
children?
 Where is evolution
taking us?
Survey of 14,000
residents of
Framingham, MA
 Begun in 1948
 Data collected on
body measurements
and health indices


◦ Blood pressure,
cholesterol, etc.
Framingham study: results



broadinstitute.org/

Steve Stearns from Yale
led study
Focused on women
Found age at first
childbirth going down
Age at menopause
going up
the-scientist.com/?articles.view/
articleNo/27545/title/Evolving-heart/
bmc.org/stroke-cerebrovascular/research/framinghamstudy.htm
Framingham study: predicting the
future


Used reproductive
success to predict
how population
would look in 10
generations:
◦ Shorter, slightly
plumper
◦ Lower cholesterol,
blood pressure
Nature as tinkerer, not engineer

yaledailynews.com/blog/2009/10/28/
stout-women-pass-on-genes-study-finds/
François Jacob, French
Nobel laureate
In 1977 Science paper,
famously described
evolution as a tinkerer,
not an engineer
◦ “To create is to
recombine.”

Always working off of
existing parts, with
tradeoffs
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4/8/2016
Evolution is good enough
Organisms are never
in perfect harmony
with the
environment
 Mismatches happen
 But we should be
wary of
paleofantasies

www.publicartarchive.org/wor
k/peace-and-harmony-nature
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