The Eagle is Back!
This aeration raises the oxygen content of the lake and allows a host of aquatic species to thrive and this in turn draws fishermen (fisherpeople?) to the park most months of the year. This ecology changes dramatically in the winter. The fountain is shut down and oxygen levels in the water drop, especially it seems when ice covers the surface. So much so that when melt spots open during the winter fish surface seeking a breath of air, often flipping themselves into the air. As luck would have it a fair number land on the ice and are unable to flap their way back to open water. The quantity and size of these stranded fish can give one pause.
Their unfortunate plight is not without a bright side. Word goes out among certain inhabitants of our city and they come like guests to a feast. These inhabitants being eagles. Bald eagles to be specific. Last winter three eagles perched on the remaining tall tree on the lake's only island and had their choice of an endless buffet of fish for weeks on end.
The lake froze solid for the first time this winter two days ago and this morning an eagle was again perched on the same tree's upper branch. But alas, the lake is so completely covered with ice that no fish have found themselves on top of the ice. The eagle has quite the patient look, feathers ruffled out against the chill.
Here in Denver the natural world has a way of seeping through our urban landscape much more than one would imagine on first thought. Walking to the park our dog insists on closely inspecting many of the storm drains seeking signs of recent activity. Both fox and raccoon use the drain system as an underground highway to traverse the city. Now that there is snow on the ground so that even I can see evidence of their presence, the dog will turn to me with an “I told you so” look. A fox popped out of a drain down the block a few winters back, right in front of us now and the dog insists that she be allowed to poke her snout down whenever we pass.
The fox, coyote and rabbit populations in our neighborhood go through cycles of sequential population spikes and then slumps. With the rabbit spikes we see and hear hawks on the hunt.
We think we live in a city but underlying or overlapping is the same natural world that was here before Denver was settled.
This thought gives rise to the rumination that we, the city's inhabitants, are ourselves as much natural wild creatures as we were before we were civilized, before we became farmers and then city dwellers. We are still those hunter-gatherers.
It seems that much of our medicine is focused on mediating the disparities between our evolutionary biology and our present modern lifestyles. How much of the complaints we see are vitamin D deficiency, melatonin suppression, and inappropriately tuned fight or flight mechanism that is triggered by innocuous stimuli? Whether by evolution or Divine Creation, we are still hardwired to live in a world far different from our present circumstances and this gives rise to some curious adaptations.
This brings to mind the various attempts people make to lead more natural lives. There's a fellow who lives a few blocks away who jogs down our street some mornings with his dog, barefoot. Not the dog but he is barefoot. I kind of get the idea of touching the world directly and that this might have some sort of esoteric or occult benefit. But something about running on asphalt seems odd, that what is communing with are refined coal tar remnants, a kind of hydrocarbon stew of putrefied prehistoric vegetation. I don't see how that is supposed to be good for you.
On the same train of thought I wonder about the insistence many people have that raw food is healthier. Certainly some foods, fruit in particular, and lettuce for sure, are best appreciated raw but the bulk of our foodstuffs are often best served cooked.
Anthropologists long thought that cooked food was a recent invention but that belief is now outmoded. Current thinking puts acquisition of fire at nearly two million years back in our prehuman past. A book called “Catching Fire” describes this in great detail. Do not confuse this book with one with a similar title that is now a popular movie and features a heroine with a bow that she uses to shoot arrows. The book I'm referring to is written by Richard Wrangham. In it Wrangham promotes what he calls, ‘the cooking hypothesis.'
The author is a professor of biological anthropology at Harvard University and Curator of Primate Behavioral Biology at the Peabody Museum. His book argues that learning to use and control fire and thus being able to cook food was the force that drove human evolution from early hominids, the habilines, into Homo erectus between 1.8 and 1.6 million years ago. Traditional thinking has it that humans evolved into about what we are today and then figured out how to use fire, perhaps as recently as 30,000 years ago. If we, as Wrangham suggests, started cooking almost 2 million years ago this is a significant change and should change what we think about food and diet.
Fire and cooked food provided an enormous evolutionary advantage. Wrangham thinks that having protection provided by a nighttime fires allowed habilenes to sleep on the ground rather than in trees, the first primate to do so. Cooking expanded the range of foods these ancestors of ours could eat. Cooking plants allowed better digestion and yielded more energy. This gave our forebears an evolutionary advantage and provided the energy and nutrients required for our brains to evolve into higher energy consuming organs.
According to Wrangham, the human body quickly adapted to eat cooked food. Mouths became smaller, jaw muscles weaker, teeth smaller, digestive tracts shorter. All these changes occurred as we adapted to eating cooked food.
“Cooked food does many familiar things,” Wrangham observes. “It makes our food safer, creates rich and delicious tastes and reduces spoilage. Heating can allow us to open, cut or mash tough foods. But none of these advantages is as important as a little-appreciated aspect: cooking increases the amount of energy our bodies obtain from food.”
Once one considers Wrangham's ‘cooking hypotheses,' it seems so reasonable an explanation that it is hard to believe that it is really a new theory. Wrangham's theory tends toward sacrilege because of what it tells us about raw food. Our naturopathic profession has ascribed to the theory that raw food is healthier than cooked food. Our theory is that uncooked food is more natural and closer to what our bodies are designed to eat evolutionarily. Wrangham theory cuts apart the assumption that eating raw foods like these is healthier and tears these beliefs to shreds. “The question,” that Dr. Wrangham poses to us is, “…what kind of diet we need…? Are we just an ordinary animal that happens to enjoy the tastes and securities of cooked food without in any way depending on them? Or are we a new kind of species tied to the use of fire by our biological needs, relying on cooked food to supply enough energy to our bodies?” If Wrangham's hypothesis is correct and at this point we have every reason to assume it is, the assumption that raw food is healthier for humans is called into immediate question.
In 2006 nine human volunteers took part in a kind of reality TV ‘experiment' that was produced for BBC television. These people lived in a special enclosure in an English zoo and ate a diet designed for chimpanzees. All their food was raw. They ate all the raw fruits, vegetables, and nuts that they could. After a week they did add some cooked fish into their diets. “The regime was called the Evo Diet because it was supposed to represent the types of foods our bodies have evolved to eat. Chimpanzees or gorillas would have loved it and would have grown fat on a menu that was certainly of higher quality than they would find in the wild.”
I've mentioned this study in years past because of what happened to the participants' cholesterol levels; they fell by 25%. What I had not realized was that the participants also lost a great deal of weight, almost ten pounds each. Certainly on the short term, losing ten pounds sounds like a good idea for some of us. Consider that these people were eating 2,300 calories per day, an amount that should have maintained their weight, and you realize that something was very wrong; they were not able to harvest the calories in the food in its raw state as efficiently as if it had been cooked. If they had attempted to continue on this diet long term they would have not had sufficient energy to meet their needs.
There is scant research published on people who choose to eat raw food. The most extensive is the Giessen Raw Food Study that used questionnaires to gather information on 513 Germans who chose to eat raw food for health reasons. As the proportion of raw food in the diet increased, Body Mass Index (BMI) decreased. Average weight loss while shifting to a raw food diet was 26.5 pounds. Of those eating a purely raw diet, almost a third suffered from ‘chronic energy deficiency.' Among women eating totally raw diets, about 50% stopped menstruating. A population that ceases to reproduce would certainly be at an evolutionary disadvantage.
It turns out that there are no human cultures on record that live on raw foods except for brief periods when they have no alternative. Certainly there are instances of people who out of necessity have survived on raw foods but none do so purposefully.
Uncooked starches of course are not only rather unpalatable they are nearly indigestible yielding about 1/3 to ½ less calories. Meat also is easier to digest and yields more energy when it is cooked. Pretty much any food that is reduced to smaller size by chopping, blending, mashing or in any way pulverizing becomes easier to for us to digest, but the best method of processing it is with heat. Cooking makes food safer, reducing risk of pathogenic infection, inactivating many poisons or anti-nutritional factors innate to particular foods.
There are certainly many foods in our modern diet that can be eaten uncooked. There are few though in this category that are not the result of careful plant breeding. Wild blueberries are the first example that comes to my mind. Of course I've always been rather partial to blueberries. That doesn't mean that they aren't better tasting and more digestible when consumed as blueberry pie. There is an obvious limit to how many raw blueberries one can eat. (as many a bear will testify to)
There are certain nutritional factors that are more abundant in uncooked foods that are reduced by cooking. This loss may not be as important as the gain in caloric utilization that cooking causes. As fascinating as this change of thinking may bring to many concepts of natural health, there is something else to contemplate here. It is the process of intellectual change. Who among us will be the early adopters and who will be the Luddites?
If Wrangham's hypothesis does prove to be true, a great many opinions about what kind of diet is healthy will have to shift. How do people let go of assumptions that they have considered true for most of their lives? In our case as naturopathic physicians, the assumption that raw is better is so deeply entrenched that it acts as the unconscious basis of much of our medical practice. All of us have encouraged patients to eat less processed and more raw foods. Many of us encourage raw food cleanses. Our advice and treatments may have been based on false assumptions.
This does not necessarily mean that these practices do not work. We have enough clinical experience suggesting that they do. It is our rationale for explaining their benefit that may be wrong. It is not that raw foods are more natural. A better possible explanation is that in some ways they are more dangerous. The sudden loss of calories caused by switching to raw food is a shock to the system and will mobilize defensive reactions. In a way eating raw is a caloric restricted diet, something we know that has profound biochemical effect. Or it could be that the fully active phytochemicals found in raw plants triggers protective mechanisms that provide health benefit. These sorts of explanations are written about under the term phytochemical hormesis. Perhaps we don't need to change our therapies as much as our rationale for using them.
We often profess to be a scientific minded profession and claim to be open minded, adjusting our thinking to new knowledge. Will we be able to think out of the box when it comes to such fundamental beliefs as raw versus cooked? Or will we react to this idea that contradicts our long held beliefs by shuttering our minds to the possibility that Wrangham is right? I hope not.
Our species face different threats today than in the past. Advanced weapons have changed the scale of internecine conflict. Our effect on global climate is about to precipitate earth's next mass extinction. The greatest challenge may not be how to confront and negate these threats. It may be to learn how to collectively and rapidly assimilate new knowledge and make intelligent and rational decisions based on it. Doing so is a rare skill to find in an individual. It is more rare to find such traits embodied in a culture or society. Yet this may be the most important thing we must learn to do both as individuals and more importantly as a society. Learning to make smart decisions may be more challenging to do than merely learning to ‘catch fire.'