What makes us human? It’s a big question.
Is it our language, our intelligence, or even
something a simple as our thumbs? Something
has to separate us from our slightly dimmer
ape cousins and ever since Darwin popularised
the idea of natural selection and evolution
academics have been arguing about what made
humans so unique and dominant. Proposed theories
include Man the Hunter, Man the Runner, and
even Man the Aquatic ape. But today we’re
going to look at a theory put forward by primatologist
Richard Wrangham, Man the Chef. Could something
like cooking have given us that evolutionary
advantage, transforming us from ape into human?
Let’s find out.
We are the only species that cooks our food.
Language, intelligence, and thumbs can be
found in other species across our planet,
but only humans get pizza.
It’s a common belief that cooking is a recent
innovation. Something Homo Sapiens invented
after already assuming our modern evolutionary
form. We imagine our natural diet as one of
raw meat, fruit, and vegetables not unlike
that of Chimps. The core belief of the Raw
Foodist movement is that we’d be a lot healthier
if we only ate raw food. Can we actually survive
on raw food though?
There are Medieval reports of Mongol soldier
riding for weeks without starting a single
fire. Draining blood from their horses for
sustenance or throwing a chunk of meat under
their saddles in the morning, which friction
would tenderise for their evening meal. Thus
inventing steak Tartare. This raw diet obviously
didn’t have any negative effects on Mongols
soldiers, judging from their ability to conquer
all the things. Many people tout this as an
example of the strength of the raw food diet.
Forgetting that as soon as they stopped riding
the Mongols were just as eager as anyone to
partake in a nice Mongolian BBQ. The Mongols
may prove that we can survive on raw food
for some time, but Wrangham believes that
we evolved to eat cooked food.
Let’s look at an experiment conducted by
the BBC in 2006. They took 9 dangerously unhealthy
people, stuck em in an enclosure in Paignton
Zoo and only feed them raw fruit, veg, nuts,
and a small amount of cooked fish. They all
ate their recommended caloric intakes, between
2000-2300 calories. For the participants the
results were great. Their blood pressure fell
to normal levels and they lost an average
of 4.4kg each. Great for modern overweight
people but if our ancestors ate such a high
quality diet, took in all their needed calories
and still lost weight it would be devastating
from an evolutionary standpoint. Chimps would
have grown fat on this diet, why didn’t
Well for one, raw food diets always result
in weight lose. Among people that eat raw
food diets ⅓ show signs of chronic energy
deficiency. In women raw foodists 50% stop
menstruating, which while protecting them
from bears, it does have serious consequences
for fertility. This isn’t an attack on the
Raw Food diet as it’s a diet many people
enjoy. However, its effects would be horrible
for the population of our hunter-gather ancestors.
Just from an evolutionary standpoint reduced
fertility in those eating raw food diets would
have given those eating cooked food a huge
We lose weight on raw food diets because cooked
foods provide more energy, calorie-wise. Energy
gain is our primary reason for eating. You
may be wondering why cooked food provides
more energy. It does so because reducing the
size of food particles through crushing and
grinding or by softening them through cooking
makes them easier to digest. Hard foods are
predictably tougher to digest, meaning that
you need to use more energy to break them
down. We even have research proving this.
Japanese scientists gave ten rats ordinary
food pellets which required a fair amount
of chewing. They gave another 10 rats the
exact same pellets except that they had been
soften by increasing their air content. Everything
else in the rats lives stayed the same. After
32 weeks the soft-pellets rats were an average
of 37 grams heavier and had 30% more abdominal
fat. Enough to be classified as obese. The
soft food was easier to digest so the rats
didn’t have to expend as much energy digesting
their food. Resulting in a net energy gain.
Ok, so cooking foods gave our ancestors more
energy. What does that mean? Well first we’ll
have to look at something called an evolutionary
trade-off. In order to increase one trait
you need to decrease another. Ostriches are
excellent runners at the expense of flying,
turtles have protective shells but sacrifice
mobility, and giraffes have long necks but
it makes shopping for scarves awkward.
During our evolution there was a digestive
evolutionary trade-off. Compared to other
apes we have tiny mouths, stomachs, guts,
and colons along with weak jaws. Wrangham
speculates that as our ancestors started eating
cooked foods everyday natural selection began
to favour those with smaller and less demanding
guts. Digestion can require as much energy
as movement does, so those with smaller guts
wasted less energy digesting their food. Smaller
guts provided an energy surplus. Our guts
are 40% smaller than would be expected in
a primate our size. So what did we trade our
digestive system for? Bigger brains! Primates
with smaller guts have bigger brains on average.
Our big brains were paid for by our small
guts. This is known as the expensive tissue
Wrangham suggests that by using the expensive
tissue hypothesis we can assume that Home
Erectus came about because of cooking. His
reasoning is that before 2 million years ago
there is no evidence of the controlled use
of fire. And after that there are 3 major
changes that result in new species of Homo.
Homo Erectus 1.8 million years ago, Homo Heidelbergensis
800,000 years ago, and Homo Sapien 200,000
years ago. He rules out the changes from Erectus
to Heidelbergensis and from Heidelbergensis
to Sapien because the changes are too small
to indicate a massive change in diet, they
were mostly physical changes in the face and
brain enlargements. So the only remaining
option is the shift from our apelike ancestors
the Homo Habilis into Homo Erectus 1.8 million
years ago. To understand why Wrangham pinpoints
this shift as the origin of cooking we need
to take a closer look at both of these species.
Homo Habilis were much better climbers than
Erectus, they were much smaller standing at
around 1.2 metres, and had much bigger teeth
than any other species of Homo. Indicating
that they chewed a lot. Habilines are so apelike
that there is disagreement on whether they
should even be classified as Homo.
Now let’s look at Homo Erectus. With their
evolution we see the largest reduction in
tooth size, the largest increase in body size
and a loss of shoulder and arm adaptations
that helped us climb. Erectus had a smaller
gut and a much larger brain, 42% larger to
be exact. They were also the first species
of Homo to spread out of Africa. These reductions
in tooth and gut size along with the ability
to move into unknown habitats show us that
Erectus had clearly developed some new way
of extracting energy from their environments.
Wrangham suggests the it was cooking.
Now that Wrangham has shown that cooking may
have transformed our ape bodies into modern
human ones he goes on to explain how it also
created our minds and societies. Let’s look
at some of the examples he gives.
Chewing: Raw food takes forever to chew. Chimps
in Tanzania spend more than 6 hours a day
chewing. Chewing is their full time job. Humans
by comparison spend very little time chewing.
If we had to eat like Chimps it’s estimated
that we would spend 42% of our day chewing.
Currently we spend less than 5% of our day
chewing. This left us with a lot of time to
hunt, invent, and eh…make more people.
Weaning: Babies are weak and constantly trying
to die. Their teeth are useless meaning they
can’t chew anything solid for years. But
softening food allowed us to switch from milk
to solid food much earlier. Giving us access
to more energy and ensuring healthier development.
Nakedness: Fur keeps animals warm and negates
the need for pants. Human however are naked
and require pants. This is fire’s fault
because fire gave us the ability to stay warm.
So those with less fur didn’t freeze to
death and luckily enough they got the benefit
of being able to run farther without overheating.
Resulting in them being better hunters and
therefore they passed on their genes successfully.
Because everyone knows the best way to land
a lady is to kill a large African mammal and
present it to her.
That’s how cooking made us human. The biological
benefits of cooking our food forged the bodies
and minds we needed to become highly intelligent
and social creatures. The rest is history…
If you found this video entertaining then
i would high recommend you check out this
video by Smart by Design. It’s about why humans
evolved bipedalism and it’s fascinating. Click
the I in the corner of the screen or see the
link in the description.
Now this is only one hypothesis out of many
on how humans evolved. I included what I think
are Richard Wrangham’s strongest points
from his book Catching Fire: How Cooking Made
Us Human. Others I left out either because
I found them unconvincing, such as his theory
on the evolution of marriage due to cooking,
and because including them all would result
in an extremely long video. I recommend you
check out his book and all of my sources in
the description. Down there you’ll also
find links to my social media and merchandise.
Thanks for watching.