Did Cooking Make Us Human? is a BBC Horizon documentary which asks whether eating cooked food prompted changes that helped humanity evolve. We are the only species on earth that cooks its food - and we are also the cleverest species on the planet. The question is: do we cook because we're clever and imaginative, or are we clever and imaginative because our ancestors discovered cooking? This film examines the evidence that our ancestors' changing diet and their mastery of fire prompted anatomical and neurological changes that resulted in taking us out of the trees and into the kitchen. - Richard Wrangham
Ever since Darwin and The Descent of Man, the evolution and world-wide dispersal of humans has been attributed to our intelligence and adaptability. But in Catching Fire, renowned primatologist Richard Wrangham presents a startling alternative: our evolutionary success is the result of cooking. In a groundbreaking theory of our origins, Wrangham shows that the shift from raw to cooked foods was the key factor in human evolution. Once our hominid ancestors began cooking their food, the human digestive tract shrank and the brain grew. Time once spent chewing tough raw food could be sued instead to hunt and to tend camp. Cooking became the basis for pair bonding and marriage, created the household, and even led to a sexual division of labor. In short, once our ancestors adapted to using fire, humanity began. Tracing the contemporary implications of our ancestors' diets, Catching Fire sheds new light on how we came to be the social, intelligent, and sexual species we are today. A pathbreaking new theory of human evolution, Catching Fire will provoke controversy and fascinate anyone interested in our ancient origins-or in our modern eating habits.
Did Cooking Make Us Human?
Chapters
Timings (where shown) are from the start of the programme in hours and minutes
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Did Cooking Make Us Human? Introduction
Food appears to be critical to our evolution; we couldn’t have become the dominant species without it, but why, and when, did our ancestors decide to cook food?
DURATION: 02:55
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Did Cooking Make Us Human? A Caveman’s Diet
Eight volunteers eat nothing but raw fruit, nuts and vegetables for two weeks. This experiment is to see how modern humans cope on a diet that was used by our ancestors 400 million years ago.
DURATION: 07:27
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Did Cooking Make Us Human? Hunting for Meat
It is believed that our ancestors’ decision to eat meat caused their brain to evolve, but how did they go about this? A professor travels to Namibia to witness how humans hunt with basic weapons.
DURATION: 07:40
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Did Cooking Make Us Human? Meat-Eating Teeth
One scientist is trying to determine when humans started to eat meat. This is done by examining the changes in dozens of ancient teeth to see what, and when, humans were eating.
DURATION: 06:34
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Did Cooking Make Us Human? Early Cooking
There are conflicting views on when humans actually began to eat meat. Yet one excavation site in Africa shows how the Homo erectus may have had the ability to cook their prey.
DURATION: 10:33
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Did Cooking Make us Human? Food and the Body
A scientist feeds mice raw and cooked food to see if there is a change in the creatures’ weight and energy levels. Another scientist sees how the stomach handles a raw and cooked potato differently.
DURATION: 09:09
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Did Cooking Make us Human? Digesting Meat
Dr Stephen Secor demonstrates, using a snake, that eating cooked foods enables creatures to save energy. This energy is used to power something far more important: the brain.
DURATION: 06:46
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Did Cooking Make us Human? Craving Food
The brain’s need for energy-rich food is being put to the test by one Doctor who is monitoring the brain’s reaction to being fed different levels of fat.
DURATION: 07:50
Credits
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Cooking is something we all take for granted but a new theory suggests that if we had not learned to cook food, not only would we still look like chimps but, like them, we would also be compelled to spend most of the day chewing.
Without cooking, an average person would have to eat around five kilos of raw food to get enough calories to survive.
The daily mountain of fruit and vegetables would mean a six-hour chewing marathon.
It is already accepted that the introduction of meat into our ancestors' diet caused their brains to grow and their intelligence to increase.
Meat - a more concentrated form of energy - not only meant bigger brains for our ancestors, but also an end to the need to devote nearly all their time to foraging to maintain energy levels.
As a consequence, more time was available for social structure to develop.
'Accident'
Harvard Professor Richard Wrangham believes there is more to it than simply discovering meat.
Australopithecus was ape-like but walked upright like
humans
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He thinks that it is not so much a change in the ingredients of our diet, but the way in which we prepare them that has caused the radical evolution of our species.
"I think cooking is arguably the biggest increase in the quality of the diet in the whole of the history of life," he says.
"Our ancestors most probably dropped food in fire accidently. They would have found it was delicious and that set us off on a whole new direction."
To understand how and when our bodies changed, we need to take a closer look at what our ancestors ate by studying the fossil records.
Our earliest ancestor was the ape-like Australopithecus.
Australopithecus had a large belly containing a big large-intestine, essential to digest the robust plant matter, and had large, flat teeth which it used for grinding and crushing tough vegetation.
None the less, it was Australopithecus that moved out of the trees and onto the African savannah, and started to eat the animals that grazed there.
And it was this change of habitat, lifestyle and diet that also prompted major changes in anatomy.
Bigger brain
The eating of meat ties in with an evolutionary shift 2.3 million years ago resulting in a more human-looking ancestor with sharper teeth and a 30% bigger brain, called Homo habilis.
The brain consumes 20% of a person's energy while
sitting
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The most momentous shift however, happened 1.8 million years ago when Homo erectus - our first "truly human" ancestor arrived on the scene.
Homo erectus had an even bigger brain, smaller jaws and teeth.
Erectus also had a similar body shape to us. Shorter arms and longer legs appeared, and gone was the large vegetable-processing gut, meaning that Erectus could not only walk upright, but could also run.
He was cleverer and faster, and - according to Professor Wrangham - he had learned how to cook.
"Cooking made our guts smaller," he says. "Once we cooked our food, we didn't need big guts.
"They're costly in terms of energy. Individuals that were born with small guts were able to save energy, have more babies and survive better."
Professor Peter Wheeler from Liverpool John Moores University and his colleague, Leslie Aiello, think it was this change in our digestive system that specifically allowed our brains to get larger.
Energy transfer
Cooking food breaks down its cells, meaning that our stomachs need to do less work to liberate the nutrients our bodies need.
This, says Wheeler, "freed up energy which could then be used to power a larger brain. The increase in brain-size mirrors the reduction in the size of the gut."
Significantly Wheeler and Aiello found that the reduction in the size of our digestive system was exactly the same amount that our brains grew by - 20%.
Professor Stephen Secor at the University of Alabama found that not only does cooked food release more energy, but the body uses less energy in digesting it.
He uses pythons as a model for digestion as they stay still for up to six days while digesting a meal. This makes them the perfect model as the only energy they expend is on digestion.
His research shows that pythons use 24% less energy digesting cooked meat, compared with raw.
So being human might all be down to energy.
Cooking is essentially a form of pre-digestion, which has transferred energy use from our guts to our brains.
According to Professors Wheeler and Wrangham and their colleagues, it is no coincidence that humans - the cleverest species on earth - are also the only species that cooks.
Horizon: Did Cooking Make Us Human? will be shown on Tuesday, 2 March 2010, at 2100 GMT on BBC Two. It will be available for seven days after that from the BBC iPlayer
Control of fire by early humans
The control of fire by early humans was a turning point in the technological evolution of human beings. Fire provided a source of warmth and lighting, protection from predators(especially at night), a way to create more advanced hunting tools, and a method for cookingfood. These cultural advances allowed human geographic dispersal, cultural innovations, and changes to diet and behavior. Additionally, creating fire allowed human activity to continue into the dark and colder hours of the evening.
Claims for the earliest definitive evidence of control of fire by a member of Homo range from 1.7 to 2.0 million years ago (Mya).[1] Evidence for the "microscopic traces of wood ash" as controlled use of fire by Homo erectus, beginning some 1,000,000 years ago, has wide scholarly support.[2][3] Flint blades burned in fires roughly 300,000 years ago were found near fossils of early but not entirely modern Homo sapiens in Morocco.[4] Fire was used regularly and systematically by early modern humans to heat treat silcrete stone to increase its flake-ability for the purpose of toolmaking approximately 164,000 years ago at the South African site of Pinnacle Point.[5] Evidence of widespread control of fire by anatomically modern humans dates to approximately 125,000 years ago.[6]
