Being Human: Biological Anthropological Views on Food and Diet

In our first year Being Human module, students study key topics in anthropology from both biological and social anthropological perspectives.  This year, our featured essay is by Abby Smith.
Abby’s bio: I came to London from Minnesota nearly two years ago and it’s been quite the journey. I went to a different uni my first year here and was ultimately unhappy with my degree and decided to switch to Roehampton to follow my longtime passion of anthropology research. After I graduate I would love to go on to get a masters degree in either evolutionary biology or primatology!
Abby Smith

Biological Anthropological Views on Food and Diet
Food is a biological necessity needed for survival by all living animals. It is the energy source that helps us to grow, repair and maintain our bodies. While this fact is universally agreed upon by the scientific community, what we eat and why we eat it, is not. Biological anthropologists look into the past at our ancestors’ feeding habits to come to conclusions about the reasons behind our modern day diets. Fossilized teeth, plant microfossils and evidence of fire use all help to explain the biological reasons on why we eat what we do.

Biological anthropologists turn to the diets of our recent ancestors and other current living primates to help explain the way we eat today. Looking at fossil records and dentition of past and present primates can give us a lot of insight into why we eat what we do and what our ideal diet could be. It can also help explain the problems with our eating habits, resulting in obesity and diabetes. All humans started out as hunter gatherers, meaning we ate what was around us and what was accessible at the time. And our closest relatives, the chimpanzees and bonobos, are mainly frugivorous, sometimes supplementing with leaves and insects (Luca, Perry and Di Rienzo 2010: 291-314). This leads many people to believe that our ideal diet can be traced back to pre-agricultural times with the paleo diet.

The paleo diet is essentially cutting out all foods that are processed, or would not have been eaten before the creation of agriculture. This means no grains and a lot less sugar. Plant microfossils that were found in the soil and stone tools surrounding past human settlements help to back this claim up as they show that our ancestors ate a variety of plants for little of the domesticated grains we see prominently in post-agricultural diets (Henry and Piperno 2008: 1943-1950). Peter Ungar (2006) in his book Evolution of the Human Diet states that we should be wary of this assumption that the paleo diet is what is best for us due to the constant change within our ancestors’ diets. There was not a lot of time, relatively speaking, between eating mainly fruit all the way through to agriculture and the sugar epidemic we see today. What Ungar means is that there was not enough time for an ideal diet to be created and the increase in cultivation of food and higher caloric options have actually been beneficial for our species as a whole as it increased fertility rates by allowing for a widely available and stable source of food so more women had the strength to be pregnant and nurse.

With the creation of agriculture, food cultivation and consumption was increased dramatically. Different crops could be harvested year-round, surpluses allowed for storage during times of drought, and the domestication of animals meant there was always a reliable source of protein. The downside to the creation of agriculture and moving further away from a hunter-gatherer life style is that we still have an instinct for survival. For most of human history, food was not always reliable and we became adapted to the taste of foods high in sugar and thus in high in calories (Jou 2017: 20-32). Cultivation of food takes away the need to search for an energy source every day and lessens the diversity of our diet. Instead of eating hundreds of different species as part of our daily diet, it was being reduced to what could be farmed and produced in mass quantities. Depending on where you lived this usually meant one type of grain, one source of protein, and a small variety of vegetables. It was a more stable diet but a much less nutritious one.

This leads into the obesity epidemic we see today. Because the creation of processed and genetically modified food came very quickly after the popularization of agriculture, humans never had time to adapt completely. High sugar foods are always available in the super market, genetically modified fruits and vegetables make for bigger quantities with higher calories with no energetic cost to consume them at all. Humans had acquired this taste for sugar as a necessity to get the calories needed for survival, but it is now resulting in overeating because these foods are always readily available. Diabetes could also be a side effect of our modern diets as in the past; hunter gatherers had a high protein and low carbohydrate type of diet relative to modern humans. This meant insulin resistance was a favored trait. When our diets shifted back to having high rates of carbohydrates, insulin resistance was still prevalent and did not have enough time to be selected against (Luca, Perry and Di Rienzo 2010: 291-314), thus introducing Type 2 Diabetes.

We know what foods our ancestors ate because of the fossilized teeth that have been found and analyzed. Teeth are the most resilient bones and are much more likely to remain intact after death (Ungar 2006). We can tell by the large back molars seen in our ancestors that we are adapted to eat fibrous foods because the large crowns on each tooth are used for grinding and chewing. In an interview conducted by GOOD magazine, four anthropologists are asked about the evolution of human diet and Peter Ungar suggests that when our ancestors’ teeth started getting smaller about 2.5 million years ago, the edges and crests that were developed allowed for the consumption of meat. Flat, large molar-like teeth are only good for chewing, with the development of sharper, smaller and more crested teeth, early Homo would have been able to chew and rip through meat, marking a significant change in the evolution of our diet (Leonard et al. 2011).

One of the other important food sources seen in Homo erectus as well as modern humans are underground storage organs or tubers (Ungar and Teaford 2002). Because long life span and long childhoods are important factors in considering what it means to be human, anthropologists look at Homo erectus’ diets as a comparison to modern humans as their fossils indicate the presence of these qualities (Ungar and Teaford 2002). The introduction of tubers to H. erectus diet coincides perfectly with the arrival and continuation of these traits. Because tubers are found underground and are rich in fiber, they make the perfect high calorie food that is also always reliable. There is no off-season for tubers, so even if fruit or meat was not available there was always a ready supply of this “fallback” food. This could be why tubers are still seen in the diets of many hunter-gatherers today, like the Hadza group (Ungar and Teaford 2002).

It is also thought that the discovery of fire and cooking have played large roles in the evolution of human diet. The paleo diet suggests that you cut out all processed foods in order to be on the ultimate health regimen, but the fact is Neandertals started the practice of processing food before consumption long before we came along as it eased digestion (Ungar 2006). Granted, Neandertals were not eating cheese pizzas and ice cream, but processing food by cooking still increased the caloric intake and required less energy to digest. By increasing the digestive rate, the glucose acquired from the food is processed faster and allows for energy to be used more efficiently (Ungar 2006).

Using fire as a tool to process food also improves its quality. The tastier the food, the more likely people are to eat it. If the food tastes better and accelerates the digestion process, it makes sense that every culture in the world has adapted to eating meals this way. Some effects of cooking on our biology could be our reduced gut size compared to other hominoids, smaller jaws and teeth and a higher rate of energy expenditure (Ungar 2006). It has been hypothesized that cooking has been used as far back as Homo erectus because of their small teeth and jaws and large range of locomotion (Ungar 2006), but there is not enough evidence of fire seen from this era to convince the entire scientific community.

Research has been conducted to find out the effects of our ancestral diets in modern people today, showing that some populations are more susceptible to certain dietary restrictions such as celiac disease or lactose intolerance. Lactose intolerance is a primitive trait. Mammals are adapted to lose the enzyme needed to process milk after the weening period (Swallow 2018: 197-219). Some populations retain the enzyme are able to digest milk throughout their lives without an issue, some believe this is due to a genetic adaption; there is also evidence of the enzymes retaining if milk is not dropped out of the diet after weening. Populations with the highest rate of lactose persistence are those from Northeastern Europe. This is thought to be due to the importance of dairy farming throughout their history (Swallow 2018: 197-219) as cultures who view cows as religious or spiritual symbols are less likely to be tolerant of dairy as they see do not view it as a source of food.

In conclusion, to find out why we eat the way do today, it is important for biological anthropologists to look into our past. Our ancestors, closest relatives, genetics, and fossils all play very important roles in hypothesizing our diet. Unlike social anthropologists, biological anthropologists look at history and anatomy to prove their theories rather than culture and society. But, because we get most of our information from fossil records, it is important to be cautious about what our conclusions are as we can only study what we see. Plant matter hardly fossilizes while animal bones preserve extremely well, this means that even if there is evidence of humans eating meat, it does not mean that plants were not a substantial part of their diet. We can make inferences based on what we see today and what we know of other primates eating, but finding direct biological evidence for past human diets can be challenging.

References
Henry, Amanda G., and Dolores R. Piperno. “Using Plant Microfossils From Dental Calculus To Recover Human Diet: A Case Study From Tell Al-Raqā’i, Syria.” Journal of Archaeological Science 35.7 (2008): 1943-1950. Web. 27 Mar. 2018.

Jou, Chin. “Make America’s (Foodways) Great Again: Nostalgia, Early Twentieth-Century Dietary Critiques, And The Specter Of Obesity In Contemporary Food Commentary.” Gastronomica: The Journal of Critical Food Studies 17.1 (2017): 20-32. Web.

Leonard, Bill et al. GOOD Asks The Experts: Is The “Paleolithic Diet” Really Better?, 2011. in person.

Luca, F., G.H. Perry, and A. Di Rienzo. “Evolutionary Adaptations To Dietary Changes.” Annual Review of Nutrition 30.1 (2010): 291-314. Web

Swallow, Dallas M. “Genetics Of Lactase Persistence And Lactose Intolerance.” Annual Review of Genetics 37.1 (2003): 197-219. Web. 27 Mar. 2018.

Ungar, Peter S. Evolution Of The Human Diet. Oxford: Oxford University Press, USA, 2006. Print.

Ungar, Peter S, and Mark Franklyn Teaford. Human Diet: Its Origin And Evolution. Westport, Conn.: Bergin & Garvey, 2002. Print.

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