Ah, our pesky ancestors! Why can’t their remains fit into a simplistic pattern that we can all just agree on!? Why do they force us to think? Remember the Paleo Bread “scare”? Early humans collected TUBERS, ground them into paste and COOKED them! This changes everything!!! Grok at Panini and Subway! Jared was right after all!
Or…it changes nothing: We know hunter gatherers exploited a wide variety of food stuffs, fire has been used for upwards of 3 million years to cook these foods, cooking dramatically improves the digestibility of starch (be it tuber or grain)…should any of this surprise us and does it change anything we understand about the molecular underpinnings of disease or guiding principle such as Evolution via Natural Selection or Optimum Foraging strategy?
No, it does not change much of anything. In fact it seems to support the evidence at hand. So, what about the recent findings of GRAINS and LEGUMES stuck in the teefs of Neanderthals? Is it time to reevaluate everything? AGAIN? Well, cool your heels Paleo-Five-0, you are all sail and no rudder. If you don’t want to fall prey to the same mistakes that the media and even folks in paleontology seem to make you need to view new data in a framework and not just a random factoid.
Ya need a model.
When I was a bright-eyed, bushy-tailed Jr. Chemist at CSU Chico, we had weekly forums featuring a speaker on chemistry, toxicology or similarly yawn-worthy topics. I loved this stuff as seeing folks from different areas always helped me come up with ideas for the research I was doing: the enatiomeric selection of pro-chiral ketones using novel reducing agents.
I told you it was boring.
Anyway, one week we had a guy present who was a candidate for a faculty position in the chemistry department. This guy was a GREAT speaker, really funny, dynamic and…he claimed to have found a reaction product that had five bonds to carbon (this is NOT related to 5 fries being the secret to a balanced hormonal profile btw). For the non-chemists out there, this is like saying you have discovered proof of honest politicians ie-Impossible. The room wound down to a bit of quiet disappointment. The folks on our faculty said things to the effect “You need to check your numbers, you have an error somewhere…” You see, what this guy was proposing flew in the face of everything we think we know about chemistry. We have things like molecular orbital theory which has basis in quantum mechanics, and although we are far from knowing everything about these topics, we have a pretty solid model and this particular piece of data would have required a complete revamping of damn near everything we know. As it turns out, this guy had calibration problems on some of his instrumentation and this artifact is what made it appear he was getting 5 bonds on carbon. It may seem hard to believe stuff like this can happen, but I was actually sitting in my high school chemistry class when this wacky idea of cold fusion was put forward and summarily dismissed. It happens. Folks generate data, get excited, don’t do their homework and leap to conclusions. In theory this is what the peer-review process is for, but it certainly has its limitations.
So, should all new ideas and findings be ignored because they do not fit our preconceived notions? Should data that is contradictory be held in high-suspicion? No, but to the best of our ability (humans are quite adept at self deception) we should hold ALL data in a suspicious position, at best with a sign “Good until further notice.”
In disciplines like chemistry, engineering and physics we have controversy but it is nothing like what we see in “nutrition science.” Fat: good, or bad? Vitamin supplements…cure ya or kill ya? These are HUGE paradigm shifting events that seem to blow in with the breeze. Why do we see nothing like this in these other sciences? Because of some basic models that guide our research and data analysis. Said another way: In chemistry, physics and engineering the data fits observations and we can (to a fair degree) predict what will happen when we change parameters of a system. Now, as nice and illustrative as all that is, chemists, engineers and the like cannot get too hoity-toity about the “soft sciences” like anthropology and biology because there are a lot more unknowns and moving parts in the world outside the test tube! Although the models that biologists and anthropologists bring to their craft are not as tidy as quantum mechanics, they are pretty damn good and in fact are indispensable if we are to make sense of things. Let’s take a look at a key model in anthropology and ecology, optimal foraging strategy.
Do you want to do a little or a lot for what you get?
Optimal foraging strategy (OFS) is a way of predicting how a given organism might go about procuring nutrition. For predators (which humans are classified) we are considering how much energy one obtains from a given food relative to the amount of energy expended to procure it. One can also add the further distinction of how digestible that food item is when considering total energy costs. This squares nicely with the expensive tissue hypothesis which we might look at in some detail if folks are interested. So, OFS puts to rest these fanciful notions that folks put forward occasionally about how our ancestors ate: “Animals are hard to catch, plants are plentiful, let’s all be vegan.” Yes, please do. In the wild. With no agriculture.
What you find is that collecting that broccoli sprig and iceberg lettuce costs more in energy than it gives us. The US government may think that deficits are the Gato’s Meow, but systems that do not crumble and fail need to keep a better eye on the accounting. If we had big, fermentative guts to convert some of that fiber into volatile organic acids that get estherified into lipids it would change things, we could survive on sticks & twigs. We would be chimps and gorillas! There is that expensive tissue concept popping up again, but I digress, we are talking OFS. Here are a few things to keep in mind:
1-We can tell quite a lot about what a critter ate based on stable isotope analysis. We can tell plant vs animal ratio’s, if that plant was a C3 or C4 plant (like corn) if the animal products were terrestrial or marine. In other words, we can tell a hell of a lot.
2-OFS describes most predator activity quite well, but there are deviations, particularly for humans. Foraging societies have/had a tendency to prize certain items above others, often to the detriment of OFS. The work of Richard Lee who studied the Kung San indicates the kung, who live in a very marginalized area (not particularly rich hunting OR gathering) will go out of their way to collect/hunt those items they PRIZE. When certain fruits come into season the kung would eat those items that were close at hand, and then work progressively OUT from camp looking for the tastier items. This would continue until the area was fairly well stripped of the CHOICE items, but leaving a host of completely edible, albeit, less desirable items remaining. This describes the “digestive efficiency” element of OFS and it is important not only in nutrient intake per calorie expended, but it also decreases/diversifies toxin load.
A real-world example perhaps? From a OFS + digestive efficiency standpoint you may be able to collect a lot of acorns easily, but you are actually better off trekking further to get blueberries, because of the low toxin load. Well, until all the blue berries are gone…then it might actually be worth your while to collect those acorns, shell them, grind them, boil them (to extract the tannins).
Uh, how about those Neanderthal teefs?
Don’t worry, I didn’t forget! So, the recent paper that found a variety of plant material in the dental calculus of Neanderthal teeth lead the researchers to conclude that “Neanderthal extinction was not due to a limited diet as has previously been suspected.” You see, when isotopic analysis of Neanderthals has been compared to that of early modern humans, it was found that early H. Sapiens made use of a broader variety of plants and animals than did their burly brethren the Neanderthal. So, it’s been assumed the less diverse Neanderthal diet might have been a factor in their demise. Now we are faced with a dodgy issue of cause and effect. Did archaic homo sapiens out-compete Neanderthals via a more diversified diet? Is the inclusion of grains and legumes indicative of a “beneficial foraging strategy” on the part of the Neanderthal or early H. Sapiens?
Chico State University: It’s not just for beer
A few weeks ago I attended a presentation by the California State University Anthropology department which looked at the prehistoric diet of the Native Americans who inhabited the San Francisco bay area. Using stable isotopic analysis the relative plant/animal intake was determined. Due to the different occurrences of carbon and nitrogen isotopes in seafood and terrestrial plants and animals, it’s possible to establish fairly clearly what folks were eating. This isotopic evidence followed clear association with refuse piles from animal butchering, shellfish collection etc. Here is what they have found in the area:
The earliest settlers to the area showed a preference for mega fauna (large animals) which is consistent with OFS. Larger animals have more energy density due to a relatively larger fat mass. This occurs linearly with increasing size of an animal and is why rabbit starvation is a problem: not enough fat as a co-factor to metabolize the protein found in small, low-fat varmits. Over time the amount of mega-fauna decreased (our ancestors appear have eaten them all), and the diets of the later inhabitants shifted towards a GREATER diversity of plant and animal consumption. Remember the Kung who would walk far and wide to eat their favorite stuff? Same thing here, only once you deplete the resources of a system sufficiently, you need to shift to diversified options that are actually less appealing. This is consistent with what we also see with the habitation of the Americas in general (the Clovis peoples may have been first, perhaps not) but we see a rapid kill-off of many of the large animals and a subsequent shift to a diversified foraging life-way, and in some cases the eventual adoption/discovery/necessity of agriculture.
What some of these researchers do not get is this: The skeletons of Neanderthals indicate they were top level carnivores (early H. Sapiens show the same thing) and it’s actually the increased diversity of the diet which is indicative of problems. “We” were just too damn good at killing things, and once the big critters are gone you start eating anything you can get. These sub-optimal items increase our toxin load (lectins from grains, legumes) decrease nutrient absorption (gut irritation due to lectins, generally less nutrient dense foods) and increase our energy cost of procurement. It has been well established that Neanderthals learned many cultural innovations from H. Sapiens including bead making and other abstract work. They might have also learned to exploit a larger variety of food from us, or not, perhaps they figured that out on their own. The reality is these foods (grains, legumes) were suboptimal in both energy density and digestibility. Richard Lee described a period of drought in which the Kung exhausted virtually all the resources of their area, defaulting to collecting wild grass seeds before the winter rains came and some semblance of normalcy returned. What was interesting then (and now) is the primitive agriculturalists living around the Kung suffered horrible losses due to the drought. The kung were much less affected than the farmers due to the ability to move and a diversity of food stuffs.
So, yes, the ability to exploit a wide variety of food is good, and may in fact make the difference between life or death, but it is NOT an indicator of a FAVORABLE nutritional state, as has been suggested by the folks doing this research. Those Neanderthal teeth might not indicate a favorable situation. It might indicate desperate measures to stay alive and that actually fits the other evidence better than this “diversity =good” theory.
So, when the next “controversial” discovery related to paleo nutrition rolls out, how are YOU going to assess that information and draw your own conclusions? Hopefully you make some use of the theories that govern this topic instead of flapping in the wind like the media.