Lindsey Friedmann

Nutritional Anthropology

Essay Exam 1

10-5-02

Nutritional Adaptation

To understand biology and culture and the way in which the two interact, we must first understand adaptation.  According to Webster’s Dictionary, “adaptation is an alteration or adjustment in structure or habits, often hereditary, by which a species or individual improves its condition in relationship to its environment.”  This means that living beings are able to change their lifestyle in order to be better suited to their habitat.

Many articles we have read this semester have studied the ways in which humans adapt to specific environments.  The most recent example is an article by Norman Kretchmer who studies the genetics of lactose tolerance among different cultures.  Lactose is a chemical found in milk which our bodies absorb using the intestinal enzyme lactase.  A majority of adults across the world are not able to correctly absorb lactose and are therefore labeled as lactose intolerant.  Kretchmer provides us with the information that not all adults are intolerant.  In fact, there are specific groups of people who are more likely to genetically inherit the gene for lactose tolerance.  In his studies he has found that these groups of people who are able to process lactose as adults have been traditionally known as milk drinkers through time.  Therefore, they have gone through an adaptation in order to utilize the foods and nutrients they have readily available.

Although the previous example is a positive way of adaptation, species are able to adapt in not so positive manners.  My favorite example is an article titled “Junk Food Monkeys” by Robert M. Sapolsky.  This article is attempting to make a parallel between humans and baboons and the ways in which their diets have negatively begun to affect their health.  Studies on Masai Mara baboons have shown that these animals have recently adapted to consuming the leftovers from local tourists.  On one hand the baboons have shown some positive effects such as maturing more quickly and surviving through times of famine.  On the other hand, the baboons are now facing problems such as high cholesterol levels and deadly bacteria that live in the rotting food they are eating.  So as you can see, adaptation is not always a good thing in an evolutionary sense.

This brings me to the issue of the Paleolithic diet versus the contemporary diet.  As we have just witnessed, baboons with high fat and high sugar diets are beginning to face some of the same problems that we as Westerners are dealing with.  In the article “Paleolithic Nutrition: A Consideration of Its Nature and Current Implications” by S. Boyd Eaton and Melvin Konner, we are confronted with the issue of Paleolithic versus modern western diet and nutritional values.  According to the authors, primates have evolved from ancestors that were primarily insectivores.  Although this way of eating was only sufficient until body size increased and we began to consume large amounts of fruit and vegetable products.  Unfortunately we have limited resources in providing us with this information since plant material is easily broken down and fossils are only available in the form of pits or nuts.  The most solid piece of evidence we have that our ancestors were primarily herbivores is the dentition.  But even here, it is known that primate’s teeth were suitable for both meat and vegetable consumption.  Our next evolutionary step was to consume much larger amounts of meat and plenty of evidence, such as animal remains and tools, have been found to prove this.

The authors then provide us with the fact that modern hunter-gatherer societies most closely resemble the human beings of studies done on a few Middle-Eastern sites where strontium levels in the bone shows an increase in the amount of vegetables consumed.  With the introduction of agriculture much more produce was consumed within human populations which caused a decrease in height of about six inches as compared to the height of earlier Homo sapiens sapiens who consumed large amounts of protein.  Although our diets are still considerably different, modern humans have finally reached a similar average height since the onset of the Industrial Revolution.

The authors claim that by studying the nutritional content of foods ate by Paleolithic populations, we are able to determine what human populations are “genetically ‘programmed’ to eat, digest, and metabolize (Eaton 64).”  The Paleolithic era began with the Homo erectus and ended with the first Homo sapiens sapiens. 

Eaton and Konner first look at the differences in types of meat that were consumed during the Paleolithic era and those that are consumed by modern humans.  The main evidence is that the amount of marbled, subcutaneous fat found in domesticated meat has much more fat than wild game.  Wild game also consists of over five times less saturated fat than supermarket meat does today.  Free range meat also has less calories and a greater amount of protein than our captive cows do.  Vegetables have also changed since the industrial revolution.  Many plants that are domesticated have more starch and less protein than are found in the wild forms. 

The author uses studies done on modern hunter-gatherer groups as evidence for what the general nutritional conditions were like during the Paleolithic era.  This seems to be a somewhat questionable way of providing parallel information because the author is constantly making reference to how varied the results may actually be.  Both energy sources and daily nutritional models yield questionable results and are only generalized calculations.  These calculations found that daily energy sources would have been about 788.2 g of game and 1463.8 g of vegetable food. 

Fat and fatty acid intake were calculated using the fat count in that of a Cape buffalo and were generally lower for earlier humans.  Cholesterol intake is thought to be about the same for both generations since the amount present in meat is unaffected by the amount of fat.  Fiber intake would have been drastically more for earlier humans as compared to typical Western diets.  Findings show that even if the amount of meat to vegetable ratio for the Paleolithic era was 20:80, the amount of nutrients consumed would have been adequate in protein, vitamin B, folate, and iron.  Many humans today have large deficiencies of these nutrients.  Overall, the “Paleolithic diet had less total fat, more essential fatty acids, and a much higher ratio of polyunsaturated to saturated fats than ours does (Eaton 68).”

I think if Eaton and Konner were confronted with the suggestion that we are equally adapted to an early primate fruit and insect based diet, they would find a way to make parallels.  This article basically pointed out similarities and differences in the nutritional qualities of wild food and cultivated food.  The authors made it clear in their studies that the ratio of meat to vegetables consumed didn’t play much of an important role in the overall nutritional value of the diet.  It is safe to say that the way in which modern food is grown, processed, cultivated, and sold is the main reason behind poor nutrition and growing waistlines in modern Western society.