forum discussion #2

BBQ Begets Bigger Brains

What makes us human? Tool use? Language? Try barbecue.

Richard Wrangham

Richard Wrangham

In the most recent World Science Forum, we brought you Richard Wrangham, author of “Catching Fire,” which argues that apes became human because they learned to cook.

Wrangham is a Harvard anthropologist who’s spent decades studying chimps in Africa. He’s also studied human diet, and he argues that the development of cooking by our ancestors was a key to unlocking human potential.

We spoke to Wrangham on the podcast. Download the interview, or listen here:

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Wrangham joined us in the forum. Read what he and others had to say, below.
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Wrangham says cooking gave early hominids access to a much wider range of foods, helped their brains grow, and gave them time to develop tools and technologies.

HC

Could you survive on raw food?  Have you tried?

Wrangham proposes that the invention of cooking led to the repression of women. But is cooking necessarily a female endeavor?

He also argues that humans instinctively like soft food. Does that fit with your experience?

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Your Comments

  1. dk

    I love hamburgers, and according to Richard, hamburger is very efficient food. It’s both ground, and cooked, which makes it soft and easily digested. So my love of burgers makes me a fully evolved human I think… I also like fries, which are soft as well.

  2. BS

    Yup, that should justify you as a human…LOL!

    • Richard Wrangham

      as a human or as a member of most other species for that matter – it looks like the pleasure in eating soft foods is pretty general… leaf-eaters prefer soft young leaves, apes preferring food cooked…

  3. Cooking pretty much allowed humans to eat meat, I think. If cooking hadn’t been invented, would humans today be mostly vegetarians? Or would they just be omnivores who get sick all the time? OR, maybe they’d be more resistant to food-borne germs?

    • Richard Wrangham

      Cooking helped us eat meat by allowing us to eat it faster, get more energy from it, and make it safer. But our habiline ancestors were cutting meat off large animals from 2.5 million years ago, and before then it seems very likely that australopithecines did what chimpanzees do, grabbing monkey-sized prey and eating them. So how did they avoid sickness? Probably from eating it fresh and whole. The big danger from bacteria comes from chopping up the meat (increasing the surface area) and letting it lie around. Some raw-foodists eat raw meat, and do fine on it. Just don’t let your steak tartare stay too long out of the fridge!

  4. BS

    So, the smart thing to do is to become a vegetarian like me. There’s less worry about bacterial infection, then.

  5. LisaGS

    If humans instinctively like soft food, then how can we explain the addictiveness of potato chips?

    • dk

      I know i may be an exception, but i’ve never liked em. i’ll take some soggy fries or overcooked pasta over chips, any day. i have finely developed soft-food sensing neurons.

    • Richard Wrangham

      Potqto chips are crisp but not hard or tough. Crispness seems no problem for the gut. Of course all that fat and salt helps!

  6. Error: Unable to create directory /home/worldsci/public_html//wp-content/uploads/2014/04. Is its parent directory writable by the server? David Baron

    Prof. Wrangham — I understand you’re currently in Africa. Where are you at the moment? Can you tell us a little about what you’re doing?

    • Richard Wrangham

      I am in France right now but in 10 days I go to watch bonobos released into the wild by Claudine Andre from her sanctuary Lola ya Bonobo; very exciting, first release of bonobos ever.

    • david kohn

      Bonobos don’t cook at all. Hours of eating — it sounds dull.

  7. BS

    Ahh…crrunchy potato chips…bring it on!

  8. Bill Gardiner

    Richard or David,

    “Leaky gut syndrome” is a broadly realized condition in western society where the frequent use of antibiotics and/or over-consumption of simple carbohydrates have lead to a yeast overgrowth often causing penetration of the intestinal lumen with fungal mycelia. Since this allows undigested food particles to enter the bloodstream (I’ve seen this in microscopically examined slides of my own blood samples), what role does the actual particle size in soft vs. raw food play in health outcomes in primitive as well as modern cuisine ?

  9. bhill

    Chewing “tough” food also takes longer to process and swallow. Could this extended time allow our brain to receive signals of “fullness” sooner than the quickly swallowed processed and cooked food that allows us to eat more than we need?

    • Richard Wrangham

      Sounds reasonable to me. But of course in an evolutionary context, our tougher foods would have been eaten at a time when over-eating was not a problem!

  10. JoeT

    Could you please explain how your model of brain development via cooking fits with reports from several years ago that mutations of myosin around 2.4 mya may have led to smaller jaws and larger brains. Do you agree with this perspective of the role of mysoin? Also, could there have been advances in brain development just due to the use of tools to cut and slice meat as you pointed out in the second comment above? In that case, which came first — the myosin mutation or the tools?

    • Richard Wrangham

      Thanks Joe. I definitely think that changes in musculature, such as occurs with the myosin gene mutations sometime in our past (maybe 2.4 mya but there is a huge variance associated with that estimate), follow from changes in our ecology and behavior. Reductions in jaw musculature would not be favored until we had a source of soft food.

  11. Katherine Caddes

    I heard about the experiment where lab rats were fed either regular rat chow or a puffed-up-with air version. [The rats who ate the puffed-up version got fatter]

    My question: were the 2 groups on isocaloric diets, or were the puffy chow rats just able to eat more?

    • Richard Wrangham

      Katherine – yes, remarkably the scientists (Kyoko Oka and colleagues from Japan) showed that the diets were isocaloric. Also, the scientists estimated the energy spent in locomotion, and found it to be the same for the two groups. So the only difference they noted was the softness of the diet – leading to the group that ate softer pellets being heavier and having 30% more body fat!

    • dk

      just to clarify — “isocaloric” means simply that they had the same number of calories. So boththe regular and puffed-up versions had the same number of calories.

  12. dan grossman

    Prof Wrangham, since you posit it was relatively easy (and quick) for Homo erectus to start cooking 1.8-1.9 million years ago, don’t you have to deal with the question of why other primates around that time did not/were unable?

    • Richard Wrangham

      Presumably it was no chance that the habilines (the group that immediately preceded Homo erectus) was already substantially bigger-brained than any other apes we have ever known about. I follow other anthropologists in thinking that this was because the habilines had developed breakthroughs in behavior and technology that gave them access to increased amounts of meat. I differ from prior anthropologists in stressing that in order to take advantage of meat, the habilines probably had to batter it (turn it into something like ground beef), and this was one possible route to discovering how to control fire, since pounding meat with rock on rock can generate sparks. But that’s a guess of course. The important thing is that the habilines were substantially smarter than chimpanzees and other great apes, so they were in a unique position to discover how to control fire.

  13. I tried a raw food diet last year. In two days flat, I had the most HORRIBLE yeast infection of my life. My gut and raw foods do NOT get along….and my jaw was sore and I had pounds and pounds of food to consume every day. Ugh. Not a pleasant experience at all, trust me…

    • Richard Wrangham

      Thanks Ann. Of course, there are nevertheless many raw-foodists who do like their diets and feel good on them. It would be interesting to try and figure out what makes some raw diets work better than others.

  14. dk

    I wonder — among current hunter-gatherers, are there are clues to what our diet might have been like a million or a half-million years ago?

    • Richard Wrangham

      David – One of the big trends among current hunter-gatherers is that in the tropics, people eat roughly half their calories from meat and half from plants (or maybe a little more than 50% from plants, such as seeds, roots, corms and fruits) – whereas in high latitudes such as the Arctic or the tip of South America (Tierra del Fuego), most or all of the food is from animals such as seals, limpets and fish. This indicates that a million of so years ago, when hunter-gatherers were mostly in tropical or sub-tropical regions and were not yet at high latitudes, their diets were fairly balanced between meat and plants. The logic is that protein is a difficult food for humans to eat unless it is balanced by lots of fat or carbohydrate. In the high latitudes, animal protein comes with blubber in mammals such as seals, so it is OK. In the tropics, the meat has low fat, and cannot be eaten without lots of carbohydrates from plant diets to balance it. So it’s the same old story – balance in everything!

  15. Jonathan Dyer

    I’m fascinated by the Japanese soft food experiment. I was surprised to learn just what a difference the softened food made to the rats. It got me thinking about the energy we spend on digestion. Has anyone ever worked out how much energy we expend on digestion every day? Also, if cooked food has an increased calorific value (I assume energy transferred in the cooking process?) does that mean that a rare steak has fewer calories than a well done steak? All fascinating stuff. Thanks for engaging.

    • Richard Wrangham

      Jonathan – I agree, the effects of softening food are amazing. In Catching Food I describe them in several ways, leaving no doubt (I hope you will agree!) how important they are. There is a good deal of data on the energetic costs of digestion in humans, and of course it depends on your diet, but the costs tend to be around 5-10% of the value of the food. In some species it is much higher – e.g. around 30-40% in some snakes fed whole animals. Your conclusion about raw vs cooked meat seems right. We know it is right for pythons — Stephen Secor led an experiment that showed that cooked meat induces 12% less energetic cost in digestion than raw meat does. It is probably similar for humans, but no such experiment has been done. So your idea that a raw steak has fewer calories than a cooked steak is basically right, although purists would point out that it has literally the same caloric value: it simply provides fewer NET calories, thanks to its higher cost of digestion (and, almost certainly, thanks to its protein being less digestible as a result of being less completely denatured — but that is another story!).

  16. Krista Roberts

    I was wondering if you had an opinion on what the first thing to cooked for food was. I heard that the jump came when we began to eat psychoactive plants. Any opinion would be very much appreciated.

    • Richard Wrangham

      Krista – I have never heard of the idea that the use of psychoactive plants paved the way for cooking – not sure what the idea would be – “Hey Zonker, I got an idea, let’s put some of our food on the fire!! Wheee!!!”? Some animals eat alcohol-rich fruit and appear to like it, so human use of mind-altering substances is less unusual than cooking. I suspect meat would have been the first item cooked because it takes a long time to chew compared to plant foods, so it was more likely that the first fire-users had some in their hands (waiting to chew it) while they were near a dying fire… and dropped pieces in by accident. But anything is possible. The fact that chimpanzees find tree-seeds naturally cooked by bush-fires suggests that the first fire-users could have taked those sorts of seeds and put them in the path of an oncoming bushfire.

  17. LBR

    So how can we benefit from this research in our day to day lives? Is the differentiation between hard and soft food just another way of saying that Americans need to eat more fresh fruit and vegetables and less junk food? Is there any processed food that is surprisingly considered tough?

    • Richard Wrangham

      Leanne, I think this is an important question and I would like to see nutritionists jump in. I have been surprised to find that some nutritionists do not accept the idea that soft foods give us more energy (I think their recalcitrance is just because they have not really thought much about it) so perhaps a first point is that we can use this research as a way to get concepts of nutritional science straight. As far as practical lessons go, your inference about junk food and fruit/veg is basically right, but Catching Fire shows more precisely than usual what is wrong with a lot of junk food: it gives you more calories than you think (from standard nutritional wisdom) that you are getting. So that should be helpful. Personally I would like to see a move towards a new form of calorie-counting that takes account of the physical state of the food, i.e. whether it is raw or cooked, how mashed up it is, etc.
      What processed food does NOT lead to roughly 100% digestibility, plus low costs of digestion? That is an interesting question. Maybe others can suggest some. Dried meat? There is no research that I know of to check the answer. Some breads with large whole grains? The answer could easily be “none”.

  18. VS

    Prof, are you vegetarian?

    • Richard Wrangham

      I am not vegetarian, but it is 32 years since I have eaten mammals except for twice under really unusual circumstances. My non-mammal-eating has nothing to do with my research on food. I just prefer not to eat anything that I would not kill.

  19. Richard Wrangham

    Thanks to all who sent in comments about Catching Fire, and dietary questions. Nutrition is a fascinating area because even though there is so much recent science, there are still so many unanswered questions – such as, how much difference is there in the caloric value of raw food vs. cooked food. More to come!!!

  20. dk

    Richard: Thanks so much for joining us. We’re looking forward to hearing about your research and your adventures, in the Congo and elsewhere.

  21. BlueHornet

    This looks cool so far, what’s up people?
    If there’s anyone else here, let me know.
    Oh, and yes I’m a real person LOL.

    Bye,

  22. Gord Wait

    I was pondering your comments on the bias towards women being the cooks in the family, even in very balanced societies, and came up with what seems like a compelling thought experiment.

    Start out with two separate tribes, one where the woman is the hunter (and the man stays home to cook) and the other is the opposite.

    If the woman has just had a baby, she has to take it hunting with her (to breast feed), now if she’s killed (hunting being a likely higher risk activity) the child dies with her, and evolutionary biologist would call that a bad idea.

    In the other case, the woman is already tied down for the first few years of birth, and from a genetic point of view the husband is expendable once he has fathered the child.

    Thus, a genetic bias towards the primary caregiver adopting the role of food prep & storage.

    Fascinating subject, I hope to get your book for my summer vacation reading next week!

    Gord Wait

  23. krishnamurthy

    cooking being assigned to woman was not a sign of exploitation;it was dvision of labour;man was more suited for hunting and gathering;so the other job went to woman;

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