thank you it's a pleasure to be here I'm an archaeological scientist and I study the health and dietary histories of ancient peoples using bone biochemistry and ancient DNA and I'm here today because I want to talk to you about the Paleo diet it's one of America's fastest-growing diet fads the main idea behind it is that the key to longevity and optimal health is to abandon our modern agricultural diets which make us ill and move far back in time to our Paleolithic ancestors more than 10,000 years ago and eat like them now I'm really interested in this idea because it purports to put archaeology in action to take information we know about the past and use it in the present to help us today now this idea was was really started in the 1970s with this book the Stone Age diet it's diversified since then into several variants including the Paleo diet the primal blueprint the new evolution diet and Neanderthal and most of the the language of these diets makes references to anthropology nutrition science and evolutionary medicine the diet does seem primarily targeted at men so if you look at advertisements and descriptions they have virile cavemen like images things like live primal lots of red meat and that can basically be the idea behind it can be broken down into four parts one is that our agricultural diets today make us chronically ill that they are out of sync with our biology and two that we need to abandon these agricultural diets that started during the agricultural period and move back in time to the Paleolithic and eat more like our ancestors over 10,000 years ago third that we know what these diets were like and what they were like was they had a lot of meat they were mainly meat-based and that that was supplemented with vegetables and fruits and some nuts and oils but it definitely did not contain grains or legumes or dairy and forth that if we emulate this ancient diet it will improve our health and make us live longer and so what I want to talk to you about today is that just this version of the Paleo diet that's promoted in popular books on TV on self-help websites and in the overwhelming majority of press has no basis in archaeological reality so thank you no I'm not going to end there I will I will explain okay so what I want to do as an archaeologist go through this do a little bit of myth-busting of some of these foundational archaeological concepts upon upon which it's based and then I want to talk to you about what we really do know from the archaeological record and from scientific studies about what Paleolithic people did eat so miss one is that humans are evolved eat meat and that paleolithic peoples consumed large quantities of meat humans have no known anatomical physiological or genetic adaptations to meat consumption quite the opposite we have many adaptations to plant consumption take for example vitamin C now carnivores can make their own vitamin C because vitamin C is found in plants if you don't eat plants you need to be able to make it yourself we can't make it we have to consume it from plants we have a longer digestive tract than carnivores that's because our food needs to stay in our bodies longer so we have more time to digest plant matter we need more surface area we need more microbes we have generalist dentition so we have big molars that are there there to shred fibrous plant tissue we do not have carnassial which are the specialized teeth that carnivores have to shred meet and we do actually have some genetic mutations in some populations that are adaptive to animal consumption but it's to milk not meet and these arose and certain populations during agricultural periods primarily in Europe and Africa the meat and I call this the meat myth it the idea behind it is that we should eat all this red meat but that's just really not true if you look at this plate of meat here for example these are from fattened cattle these are domestic animals anything a Paleolithic person would have eaten would have probably been very lean probably small and they wouldn't really have eaten that much meat of course there's also bone marrow and organs these would have been very important we see evidence of harvesting a bone marrow and faunal assemblages where you see characteristic cutting open of the bones like you see here for marrow extraction now sure people did eat meat and especially in the Arctic in areas where there's long periods where plants are not available they would have eaten a lot of meat but people that lived in more temperate regions or tropical regions would have had a very large plant portion of their diet so where does this meet myth come from there's really two places and one is the inherent bias in the archaeological record bone is eighty percent mineral by weight it's going to preserve better and longer over thousands of years the delicate plant remains but the other issue comes from some early bone biochemistry studies that were performed on Neanderthals and early people this bow and biochemistry study is based on that something called a nitrogen stable isotope analysis it's complicated but I'm going to try and break it down the basic idea is that you are what you eat and so we there's 915 and nitrogen 14 have heavy and light versions of nitrogen and we consume this nitrogen in our food but was there's one important difference and that is with each step that you go up the trophic hierarchy the amount of the heavier isotope increases so if you measure the amount of heavy isotope in the bone you can infer where that individual was on a food chain this is an example of a generalized isotopic model and I've plotted where plants generally fall and then above them or the herbivores and then above them the carnivores but one of the problems is is that not all ecosystems conform to this model there's a lot of regional variability so if you don't understand the region you can come to erroneous conclusions so I'm going to give you some examples we can take East Africa if we measure animals and humans ancient humans in East Africa we see some very strange patterns first of all how can a human be higher than a lion Lions only eat other animals and then how is this herbivore above a lion well it turns out that the food that you eat is not the only contributor to these isotope expand that aridity can also have an impact so what we're likely seeing here is differences in water access so let's move out of the savanna and move into the tropical areas let's look at the ancient Maya again we see something anomalous we see the ancient Maya lining up with Jaguars now we know the ancient maya had diet heavily reliant on corn so what's happening here we don't exactly know but we think this may have to do with the way they performed agriculture and how they fertilize their crops now let's go to the Pleistocene we see some really interesting patterns year two we see reindeer flooding very low in the range of plans we see wolves plotting normally where you would see herbivores and we see mammoth spanning all three levels at once plants herbivores and carnivores so what we think is happening here is that in very very cold climates animals eat unusual things and in this case we think what is happening is these mammoths are eating lichens and bark that's giving them very strange values so if we now go to humans ancient humans pale of the humans and Neanderthals we see that they plot in the same isotopic space as Jaguar or as wolves and hyenas now that's true but as I've shown if you don't have a good control over the regional isotropic ecology you can come to an erroneous conclusion and I think it's premature to say this is very strong evidence of meat consumption given how very little we really know about the Paleolithic ecosystems so myth 2 is that pale of the peoples did not eat whole grains or legumes now we have stone tool evidence from at least 30,000 years ago that's 20,000 years before the invention of agriculture of people using stone tools that look like mortars and pestles to grind up seeds and grain more recently we've been developing techniques where we can actually measure this thing called dental calculus it's very interesting it's fossilized dental plaque we can go into the individual mouths of people pull out that plaque and recover microfossils of plants and other remains my team is working on developing methods to extract DNA and proteins and other research groups are focusing on these microfossils like starch grains paulandan phytoliths now we're still in early days here but even with the limited research we have we can say that there is an abundance of plant remains inside the dental calculus of Paleolithic people's and these things include grains including barley refining barley inside Neanderthal teeth inside the plaque we also have legumes and tubers so myth 3 is that pale Paleo diet foods in the diet fad diet are what our Paleolithic ancestors ate that's just not true every single food that's pictured in these advertisements are all domesticated foods they're all products of farming of Agriculture there from the Neolithic transition so let's give an example let's take bananas bananas are the ultimate farmers food they can't even reproduce in the wild anymore we've actually bred out their ability to make seeds so every banana you have ever eaten is a genetic clone of every other banana grown from cuttings they're definitely a farmer's food if you were to eat a wild banana it is so full of seeds that I bet many people in this room wouldn't even recognize it as edible let's take salads that seems like a really great Paleo diet food except that we've radically changed the ingredients to suit our needs so wild lettuces contain a great deal of latex which is indigestible and irritates our gastrointestinal system that it's bitter the leaves are tough we've domesticated them to be softer to press bigger leaves to remove the latex in the bitterness remove the spines that naturally grow on the leaves and stems of wild varieties to make them taste here for us the tomato that's shown here does it lacks the Tomatina and solanine toxins that are press and it's wild relatives which are all members of the poisonous nightshade family if we look at oil it's true that olive oil is the only natural vegetable oil that can be harvested without synthetic chemicals except it still requires at least rudimentary presses to remove it something that no Paleolithic person would have ever built is a farmers food this is a model diet I found on a website it looks like a delicious and nutritious breakfast and I'm sure it is but it's not something a Paleolithic person would have had access to first of all the blueberries are from New England the avocados are from Mexico and the eggs are from China which would have never appeared on any Paleolithic plate unless we have this problem of size domestic blueberries are twice the size of wild blueberries we've already talked about bananas you look at avocados a wild avocado has maybe a couple millimeters of fruit on it and the same goes for wild wild olives and of course chickens chickens are prolific producers they lay eggs almost every single day they're predictable large and abundant if you're trying to collect wild eggs they don't lay you're around and they're not as easy to find and they're typically small but maybe you're not convinced so I'm going to give just a couple more examples so this you may all recognize as broccoli broccoli did not even exist in the Paleolithic period what you see on the left is wild broccoli looks quite different now wild broccoli is also wild cabbage wild cauliflower wild kale wild kohlrabi and wild Brussels sprouts they're all the same species the only difference is they're different cultivars we've selectively bred the same species to produce the kind of food that we like best these are human inventions broccoli i think is an interesting example because it's this weird thing what even is broccoli it's such a strange looking vegetable in case you don't know it is it's flowers it's the flower of the plant we've we've created we've changed this wild plant into something that produces so many dents flowers that it produces this odd stock like thing if you but it is flowers if you don't believe me buy some broccoli at your grocery store put it in a vase like I did on the and it'll bloom it makes a lovely lovely bouquet so let's talk about carrots next so you all recognize the carrots on the right but wild carrot is what's on the left it contains fell care and dial and other things that are natural pesticides they're bitter and flavor and they taste really bad and we've bred them out and we've also expanded them made them much bigger much sweeter and and much more full of vitamins because that's what we want many of you may not know this but almonds and apricots are extremely closely related species of prune the main difference is we've bred out the cyanide and almonds so that we can eat the seed and we have and we've selected for bigger thicker fruits and apricots because that's what we want to eat from that particular species but they're very closely related and like carrots and broccoli they're essentially human inventions so let's talk about some real paleo diets well first of all I need to care I need to clarify that there is no one paleo diet there are many many paleo diets people when they spread out across the world colonize the continents they ate local foods and of course they were extremely variable so when we speak about Paleolithic diets it's very important to speak of them in the plural let's take a closer look at one in particular when I go 7,000 years back in time to oaxaca mexico and right now you're looking at the view outside of the gil oona keats rock shelter where the earliest sites in Mexico this is a photograph that I took in December and what your people would have been living here at this time and what you were essentially seeing right now is dinner and this is a far cry from anything that she would find on the Paleo diet and anything you'd find in your modern soup supermarket but there was plenty of food here for people to eat on a seasonal basis so September was high time at gillan tahquitz this is when a lot of people would have come in and occupied these rock shelters and they would have eaten the locally available resources and if you notice this includes a lot of fruit legumes agaves that's what we make a tequila from today various nuts and beans and squashes and wild game predominantly rabbits but by the time April came around there was very little edible food in this region so they would have moved on to other places where food was more abundant and so if we take a step back and we'd say well what can we really learn about the Paleolithic diets around the world there are some general observations we can make one is that they are regionally variable people who live in the Arctic have and always will eat something different than people who live in the tropics they have different resources so people who live in places where there are no plants tend to eat more animals and people who live in places where there are plants to eat more plants and they're going to be seasonally variable because plant seed and fruit at different times herds migrate and fish spawn on a seasonal cycle as these things happen people have to move from research patch to resource patch which means that there is periodic high mobility sometimes over long distances but once again it depends on the region food packets were generally small if you're going around collecting wild broccoli you're going to have to collect an awful lot of it to be the equivalent of its domesticated variety the foods that you would have collected would have been generally tough woody and fibrous you would eat meat but you would also eat the marrow and the organs of the animals you collect and they generally be very lean and finally the plants you would eat would still contain a lot of toxins at various levels and phytochemicals some of which actually have very good health benefits but it's almost impossible for us now to eat this sort of diet three billion people cannot eat like foragers on this planet we are simply too big so can we take lessons from these politically still can't apply to our lives today and the answer is yes I think there's three main lessons we can learn first there's no one correct diet but diversity is the key so depending on where you live you can eat very different things but you need diversity we lack the ability to synthesize many nutrients that we require for life nutrients and vitamins we require to get them from our foods so eating a diet that's rich in species has high species diversity is very important now unfortunately in American diets today the trend is going the opposite direction if you go when you take a process food off a grocery store shelf it doesn't really matter if it's cake batter mayonnaise or coffee creamer increasingly there's only three species and almost everything we eat you have corn soy and wheat that's the opposite direction we need to be going second we evolved to eat fresh foods in season when they're right that's when they have their highest nutritional content but of course we have to also talk about food storage and preservatives because in large urban societies you can't always eat everything fresh food spoils some foods preserve naturally well these include things like seeds and nuts and that's why traditionally they've been so important agricultural populations but we can preserve them in other ways through salting through sugar through vinegar we can pickle them we can smoke them we can dry them and we can add artificial preservatives now what I find very interesting about this is that these all work in the same way they work by inhibiting bacterial growth but we have to keep in mind that our our gastrointestinal systems are also full of bacteria good bacteria that do many good things for you they digest your food they regulate your immune system they promote mucosal function if you're eating foods full of preservatives how does that affect your microbiome your good bacteria within you and the answer is we really don't know and it's something we're only starting to investigate and third we evolved eat Whole Foods in their complete package with their fiber and their roughage and everything it turns out this is really important that your foods are not just the sum of the calories and the vitamins but even the parts you can't digest are very important the fiber that you eat regulates the speed at which the food travels through your gut it modulates metabolism slows down the release of sugars it has all sorts of functions it feeds the good bacteria that live in your gut and increasingly we're seeing that low fiber diets are associated with microbial communities that cause things like obesity and diabetes what's unfortunate also in the the globalized system of processed foods is that we're losing these connections we're losing the whole food and we're eating reconstituted concentrated foods and we don't get the benefits of having for example the fiber and the pectin and a fruit juice because it's been filtered out we're losing all of this balance and as an example of how this thing gets so out of balance we can eat so many more calories so much more food in a very small package without realizing it and that short-circuits our abilities to to know when we're full and when we've had enough so I have a question and my question is I was wondering is anyone here know if you take a soda let's say a 34 ounce soda which is increasingly becoming the normal size like this one here and you drink it imagine that you're back in the Paleolithic period and you want to consume the equivalent amount of sugar how many how much sugar cane if you stumbled upon sugar cane field how much would you have to eat do you think how many feet of sugar cane do you think do you think you'd have to eat I brought some sugar cane how many feet of sugar sugar cane do you think you'd have to consume to reach that level any ideas one how many sticks do you think you'd have to eat you're pretty big not quite 40 feet you have the 8.5 feet of sugar cane to reach to reach that level that's an awful lot of sugar there is no physical way that a Paleolithic person could have possibly eaten that much sugar cane even if they really really wanted to and now you can consume it in about 20 minutes so we've by decoupling the whole food from the nutrients inside of it we trick our bodies and we can we can override the the mechanisms that we've evolved a signal fullness and satiation and these are the three main lessons I think we can learn from real pale ethic diets there's no one correct diet but dietary diversity is key that we need each fresh foods when possible and that we need to eat whole foods so anthropology and evolutionary medicine have a lot to teach us about ourselves and new technologies are opening up new windows into the past but we still have a lot to learn from our paleo ethic and our Neolithic ancestors .
Video Description:
TED Fellow Christina Warinner is an expert on ancient diets. So how much of the diet phad the "Paleo Diet" is based on an actual Paleolithic diet? The answer...
