Here's my paper. Feel free to be bored or discontinue reading now, although it is really interesting. It's about the evolution of food and the way humans eat since pre-agriculture.
Modern humans have been on this
earth for an estimated 200,000 years. In the past 12,000 years or so though,
the way humans have eaten has changed dramatically. We have gone from being entirely hunter-gatherers
to being agriculturalists to being customers in grocery stores and fast food
restaurants, which are part of the uncontrollable food market we have today in
this country. Obtaining food used to be the main daily chore of hunter-gatherers,
but now Americans spend a mere 10% of their income on food (and 4% on eating
out) (Akst). Food is something that
humans always have and always will need, though, and it has evolved over the
course of human existence to fit our needs, based on our eating preferences of
each particular time period. These changes have had some dramatic implications
for the societies that we live in today and the way we ourselves live our
lives.
If
we went back in time to over 12,000 years ago, we would see a very different world. There would be no cities, no buildings, no
roads, and many, many fewer people than there are today. Scientists estimate that there were only
between 1 and 10 million people on earth during the pre-agricultural era
(Eldredge). Today there are about 7
billion people on Earth, but this exponential growth did not occur until the agricultural
evolution, as previous to this, population growth was very slow (Cohen).
Societies
then were much smaller, and they were mobile (Cohen).They had to keep moving around
from place to place to find food to eat.
If one group stayed in one place too long, everything edible within
walking distance would soon be gone.
This is the reason they did not put up permanent shelters; they would be
leaving again soon.
It
has been estimated that hunter-gatherers spent approximately 6 hours a day
hunting and foraging for food (Belovsky, 45).
Jared Diamond points out that the Kalahari Bushmen, who continue to live
a hunter-gatherer lifestyle, only spend between 12 and 19 hours a week
obtaining food (Diamond). Although it is
generally regarded that hunter-gatherers lived a “nasty, brutish, and short”
life “it turns out that these people have plenty of leisure time, sleep a good
deal, and work less hard than their farming neighbors” (Diamond).
In
fact, many anthropologists and nutritionists alike are beginning to think that
hunter gatherers may have had a healthier life than the agriculturalists that
took their place. This is perhaps one reason that the way we ate stayed
stagnant for so long: it was keeping us healthy, and we did not need to change
it. This was also the main period of time that humans did not have control over
their food, so therefore the food did not adapt and change to fit our needs
like it has more recently in history.
Diamond notes this about surviving hunter-gatherer
populations: “While farmers concentrate on high-carbohydrate crops like rice
and potatoes, the mix of wild plants and animals in the diets of surviving
hunter-gatherers provides more protein and a better balance of other
nutrients.” (Diamond B). We have to
assume that this is also the case for earlier hunter-gatherers as well. In his
opening lecture at the summer meeting of the Nutrition Society, Boyd Eaton
described the estimated hunter-gatherer diet, and it was much different than
how we eat today. First of all, our ancestors ate much more meat when it was
seasonably available. They ate
approximately 3g/kg of body weight of protein each day (Eaton, 1). Today, we
are recommended to eat only .8g/kg of body weight of protein each day (Blake,
242). Meat is very calorically dense compared to vegetables, so it is believed
that they would eat it as much as possible.
Bringing down a large animal is much quicker, less labor intensive, and
more filling than spending all day foraging for edible plant foods. It is
important to note though that the average American today consumes between
11-12% of their total calories from saturated fat, while hunter-gather’s only
consumed about 7.5% of their calories from saturated fat (Eaton, 1). Saturated fat most often comes from animal
products, so although we would expect it to be the other way around, this
discrepancy can be attributed to a quality issue: “While its composition varies
seasonally, the fat of wild animals tends to have more MUFA and PUFA and less
saturated fatty acid than is found in supermarket meat” (Eaton, 3). (MUFA:
mono-unsaturated fatty-acid PUFA: poly-unsaturated fatty-acid) In other words, the meat we eat today has a
higher saturated fat content as compared to the wild game that was hunted
pre-agriculture. This is due to certain agricultural practices that will be
discussed in more detail later as we move forward in time to the present. Hunter gatherers also have substantial
cholesterol intake at about 480 mg/day due to the large amount of animal
products that were eaten (Eaton, 1).
Almost all the
carbohydrates hunter-gatherers ate derived from fruits and vegetables, and
since 35% of their calories came from carbohydrates (Eaton, 1) and we know fruits
and vegetables are very low in calories, they must have been eating a lot of
them to make up this percentage. Americans
today eat a far higher percentage of their calories from carbohydrates, and
nearly all of those come from grain products and added sugars, not fruits and
vegetables like they used to (Cordain, 342).
While hunter-gatherers may have encountered the occasional honey, there
is no other evidence that they ate much grain or other types of sugars at all
(Eaton, 1). Furthermore, there was no milk or other dairy products in their
diets (after weaning, of course) because milking animals is an agricultural
practice that had not yet been developed. Cordain, et al says, “Although dairy
products, cereals, refined sugars, refined vegetable oils, and alcohol make up
72.1% of the total daily energy consumed by all people in the United States,
these types of foods would have contributed little or none of the energy in the
typical preagricultural hominin diet” (Cordain, 342). So it is clear that our
diets have changed dramatically since this time.
It is also
interesting to note that in addition to the quality issue that arises with
animal fat content due to agriculture, there is also a quality issue that
arises with fruits and vegetables due to agriculture. There is an approximate 133g of fiber per kg
of weight in uncultivated produce, while produce grown on the farm has only
42g/kg. (Eaton, 4). Also, “Wild plant foods known to be consumed by
hunter-gatherers generally maintain higher micronutrient concentrations than do
their domesticated counterparts, as does the muscle meat of wild animals.”
(Cordain, 348) As farms get older, the
nutrients in their soil gets depleted, and fewer nutrients are transferred into
the edible part of the plant. Natural ecosystems, however, keep soil fertile so
not only do the fruits and vegetables contain more micronutrients, but so do
the wild animals that eat them. “Vitamin, mineral, and (probably) phytochemical
intake was typically 1.5 to eight time that of today” (Eaton, 1).
Katharine
Milton points out, though, people ate a varying diet depending on where they
lived, and “we do not know much about the range of foods our paleolithic
ancestors ate each day or season in almost any environment, although it seems
likely that periods of relative food abundance may have alternated with periods
of low food availability in many environments” (Milton). So although it may be
hard to say exactly what they ate, we can make educated guesses based on what
region they were in and what naturally grows/grew there. Milton also brought up another way in which
the way we eat differs from the way our paleolithic ancestors ate: they
experienced feast and famine regularly.
It is easy to image that if you are foraging for all your food, during
the summer there is probably a lot to eat, and during the winter there is
probably very little to eat, depending on the environment you live in. So, it is believed that if there was an
abundance of food, hunter-gatherer’s would eat as much as possible, because “no
food is grown and little is stored, [so] there is little respite from the
struggle that starts anew each day to find wild foods to avoid starving”
(Diamond B). This way, when the time
comes that they are unable to find food, they have internal body fat stores to
keep them alive until the next abundance. Today, most of us do not have this
problem: we have whole grocery stores full of food right at our fingertips. This is due largely in part to the
development of agriculture.
In his article, Archaeological Evidence for Population Pressure in Pre-Agricultural Societies, Mark Cohen argues that the growing population was the reason humans began utilizing agriculture. “Changes in food refuse and food related artifacts … suggest changes in exploitative patterns which in turn can reasonably be assumed to result from population pressure (Cohen, 472). In other words, because human population was already beginning to expand, there was a demand for a new way of eating that would provide more calories and be able to sustain more people. Thus, agriculture began.
In his article, Archaeological Evidence for Population Pressure in Pre-Agricultural Societies, Mark Cohen argues that the growing population was the reason humans began utilizing agriculture. “Changes in food refuse and food related artifacts … suggest changes in exploitative patterns which in turn can reasonably be assumed to result from population pressure (Cohen, 472). In other words, because human population was already beginning to expand, there was a demand for a new way of eating that would provide more calories and be able to sustain more people. Thus, agriculture began.
Agriculture was
first developed in Southwest Asia (known as the fertile crescent), in 8500 B.C.
They began farming wheat, peas and olives, and domesticated sheep and goats
(Diamond A, 98-99). Although not stated explicitly, this is possibly because
this is where the greatest population pressure existed. Agriculture developed independently of this
in at least 4 other locations around the globe: China, Mesoamerica (Southern
Mexico and central America), the Andes in South America, and the Eastern United
States (Diamond A, 98), and the practice spread around the world from these origins
because agriculture is an efficient way to get more food for less work. “Just
imagine a band of savages, exhausted from searching for nuts or chasing wild
animals, suddenly gazing for the first time at a fruit laden orchard or a
pasture full of sheep. How many
milliseconds do you think it would take them to appreciate the advantages of
agriculture?” (Diamond B).
So although a
population pressure may have been the reason agriculture was developed, it also
propagated population growth in a huge way. First, more calories means more
people. “One acre can feed many more herders and farmers—typically, 10 to 100 times
more—than hunter-gatherers” (Diamond A, 88). Domestication of animals was also
a very important part of this because it fed people in 4 ways: obviously the
meat of the animal and the milk of the animal was direct food, but also animals
produced fertilizer for crops, and they pulled plows to increase crop yield
(Diamond A, 88). Aside from producing more
food, agriculture allowed people to stay in one place. This further increased population growth
because mothers could have babies more frequently. When moving around with a band, a mother has
to carry her baby until he/she can walk well enough to keep up, so she cannot
have another baby until then. This is
usually about four years, and is done by abstinence, infanticide, and abortion
(Diamond A, 89). Families who are stationary, however, can have as many
children as they can feed, which means every having a baby every 2 years on
average (Diamond A, 89). In this way,
agriculture increased human fitness, because more babies were being born to
agricultural societies than hunter-gatherer societies. This in turn increased agriculture’s own
fitness, because humans are ultimately in charge of agriculture. Increasing
human fitness was the mechanism by which agriculture propagated itself.
While it may seem
that this increase in calories and people would mean an increase in health, as
mentioned before, that was not necessarily the case. “Hunter-gatherers enjoyed
a varied diet, while early farmers obtained most of their food from one or a
few starchy crops. The farmers gained
cheap calories at the cost of poor nutrition” (Diamond B). This is quantifiable by looking at skeletons. At the end of the ice age, the height of
hunter-gatherers was 5’9” for men and 5’5” for women. By 3000 B.C. (approximately 5,000 years after
agriculture was adopted) height crashed to an average of 5’3” for men and 5’0”
for women (Diamond B).
Agriculture also
ran dangerous risks. If one crop failed,
farmers ran the risk of starvation. Diamond, talking about present day Kalahari
Bushmen, says, “It’s almost inconceivable that Bushmen, who eat seventy-five or
so wild plants, could die of starvation the way hundreds of thousands of Irish
farmers and their families did during the potato famine of the 1840’s” (B). So, even in early agriculture all the way up
to the past 100 years or so, we see nutritional problems that arose due to
agriculture, which haven’t been completely resolved even today (although much
of the height we lost during the early agricultural period has been regained.)
But, even though
people’s health may have suffered, their fitness levels soared. Another reason that agriculture benefitted
humans (i.e. another way in which it showed humans that it was worthy of
staying around and therefore propagated itself) was the ability of the food to
be stored. This helps to resolve the
issue of feast and famine (which humans probably didn’t enjoy too much, and
therefore favored a food that would abolish it), because agriculturalists could
eat even after the crops stopped producing food. After harvest, surplus of
crops could be placed in cellars and kept for a long time. There is even evidence
that sophisticated granaries like this existed in the Jordan Valley 11,000
years ago. They were designed with
suspended floors for air circulation and protection from rodents, and located
between the now possible residential structures (Kuijt). This could not happen for hunter-gatherer’s,
as they were constantly on the move. Not
only did this early food storage idea pave the way for many of the products
that we now eat, it also allowed for accumulation of wealth and a monetary
system. People could now use grains and spices for bartering, which further
spread the idea of agriculture across the globe.
Another reason
agriculture was beneficial to humans was that while hunter-gatherers spent all
day looking for food, agriculturalists only needed a few people to attend to
everyone’s food. Not only did this
solidify agriculture’s place in human’s eating, but it also allowed the development
of specialization to create new tools, art, technology, etc. As this specialization became more prominent,
many people’s relationship to food became one of simply eating, not gathering,
hunting, or cultivating anymore. As we work our way from the agricultural
revolution to the industrial revolution, a period of over 9,000 years, we see a
lot of technologies develop, and a significant rise in global population.
With more and more
people going to work in factories and jobs away from the farm, farmers began to
become fewer and far between. Farmers
also continued to refine their technology to grow the most food they could they
during this time. As Gretel H. Pelto and Pertti J. Pelto said, “Population
pressures have triggered the intensification of food production techniques” (513). So while Cohen believes that a population
pressure is the reason agriculture developed in the first place, Pelto and
Pelto believe that further refinement of our agricultural production techniques
were necessary to continue to sustain such population pressures.
If we look at
modern farming practices, we can see some of these techniques that allow us to
produce more food for less work. For
example, in his book, The Omnivore’s Dilemma, Michael Pollan describes how corn
has been bred to be a more efficient crop. The varieties of corn that we grow
today have been selected for to grow close together and produce the most
bushels per acre. In the 1920’s, the average was about 20 bushels per acre, but
with our new varieties of corn, farmers can grow 180 bushels of corn per acre
(36-37). This demonstrates how farming
has evolved since early agriculture, or even relatively recent
agriculture. This was done to fit the
needs of humans (the environment that the food is evolving in), because we see
a lot of delocalization during this time. This means that “food varieties,
production methods, and consumption patterns are disseminated throughout the
world in an ever-increasing and intensifying network of socio-economic and
political interdependency” (Pelto, 507).
In other words, the consumer of the food is growing ever-distant from
the production of the food.
In order to get food now, humans had to start
paying the farmers for it. In the past, small societies would work together to
obtain food for everyone (be it hunting and gathering or harvesting crops) and
it would be produced very close by.
However, with the rise in population and the relatively few farmers,
this was no longer the case. Grocery stores, whose predecessors were trading
posts, became more and more common because consumers had to begin paying the people
who produced the food they were eating, and the farmers had to have a way of
getting it to the consumer. The first self-serve grocery store, The Piggly
Wiggly, opened in 1916, and as Pelto and Pelto note, “The growth of commercial
food distribution networks has been intricately related to the development of
food processing technologies.” (Pelto, 514). So while humans have become more
distant from their food, food has also become more processed and storable. This
is so that it can be transported and have a longer shelf life at a grocery
store, which is a trait in food that humans needed to survive at the time. They weren’t out gathering or harvesting
their own food, so the food that was able to stay fresh long enough to get to them
is the food that was favored. Canning is
an early example of food processing with the intention of giving food a longer
shelf life. It was developed in the 1790’s
and is a still a process we use today, along with many other food storage
techniques.
Much of our
ability to produce the shelf-stable food we have today though is our ability to
process our crops well. Corn is one of the most processed plants in our
country, and plays a pivotal role in our food system. In this sense, corn has done very well for
itself evolutionarily: “The plant—whose prodigious genetic variability allows
it to adapt rapidly to new conditions—made itself at home in virtually every
microclimate in North America; hot or cold, dry or wet, sandy soil or heavy,
short day or long, corn, with the help of its Native American allies, evolved
whatever traits it needed to survive and flourish” (Pollan, 25). The government subsidizes corn, making it a
very commonly grown crop and a very cheap crop to purchase, and we have
developed techniques to process and break down the kernels and use them in a
variety of ways and in a lot of food products (Pollan, 15-56). Pollan describes
the breakdown of corn and all of its uses, from the yellow skin to the germ to
the endosperm, the most important part:
This oversized
packet of starch is corn’s most important contribution to the industrial food
chain: an abundance of carbohydrate molecules in long chains that chemists have
learned to break down and then rearrange into hundreds of different organic
compounds—acids, sugars, starches, and alcohols. The names of many of these compounds will be
familiar to anyone who’s studied the ingredient label on a package of processed
food: citric and lactic acid; glucose, fructose, and maltodextrin; ethanol (for
alcoholic beverages as well as cars), sorbitol, mannitol, and xanthan gum;
modified and unmodified starches; as well as dextrins and cyclodextrins and MSG,
to name only a few. (86).
If we look around a grocery store
today, we see brightly colored boxes and packages that scream “buy me” on them,
and each and every one of them most likely contains a chemical derived from
corn. Humans have options that they have
never had before due to processing techniques.
All of these food items most likely have some sort of preservative in
them as well. “From 1949 to 1959,
chemists came up with over four hundred
new additives to aid in processing and preserving food” (Levenstein, 109). These include calcium
propionate, which extends the shelf life of breads and other baked goods,
chemicals that prevent fat from going rancid, chemicals that stop color from
fading, smootheners like hydrolyzed starch to give great texture to things like
gravies and puddings, and things like monosodium glutamate that simply made
things taste better (Levenstein, 109). But, a large part of the food system we are
all a part of is food marketing. The
vice president of General Mills explained to Pollan that the reason it would be
hard to sell more whole foods (what humans have been eating for thousands of
years) is that it would be hard to distinguish one company’s products from
another. Instead, we process the whole food and turn it in to something new and
desirable that people will want to buy. Making money has become the primary
goal of our food system (Pollan, 96).
Marketing can be
looked at as a mechanism that processed food has used to propagate itself
through human eating habits. It is unique to processed foods because just as
the vice president of General Mills said, you can’t market an apple. It is what it is. But, if you take a shelf stable food product
and put it in a box on a shelf, you can compete with other boxes on the
shelf. And obviously this mechanism is
working, because a large percentage of the food we now eat is in this
form. So, what is it about our lives
that make this type of eating ideal? There
are three things: convenience, taste, and price.
Convenience is
food trait that has been highly selected for in our busy, everyday lives. “After
World War II, technology accelerated the centralized processing of food, which
helped pave the way for women to pursue paid work outside the home.” (Akst)
They didn’t have to spend all day cooking a meal because of new freezing and
packaging techniques that allowed prepared foods to stay better preserved. So because
this type of eating has lined up with human ideals about getting out of the
house and getting a job, it has thrived in this environment.
Second, these
processed foods taste good. Taste is a
sense that is well rooted in human evolution, especially sweetness, which is a
taste found in almost all packaged, processed foods. There are several theories about why humans
crave sweetness. First, there is a lot
of glucose in human breast milk—it is very sweet. Without a preference for sweetness, a
hunter-gatherer baby’s fitness would decrease dramatically (Longchamps). Second, evolutionarily sweetness is a taste
we did not get to experience very much—only if we found some honey or during
the summer when fruit was in season. Even when we began growing sugarcane, “it was
a rare and costly luxury until cane production was initiated in the New World”
(Pelto, 515). However, sweetness related to readily available energy, so it is
something that we would have wanted. “Add
fat or sugar to anything and it’s going to taste better on the tongue of an
animal that natural selection has wired to seek out energy-dense foods”
(Pollan, 107). So, today when there is
definitely no shortage of sugar and high-fructose corn syrup, humans are
perfectly happy to allow these products to flourish, because it suits our
biological predisposition.
The third reason
that we now enjoy so many processed foods is that they are cheap. As mentioned before, Americans spend
relatively little of their income on the food they eat. This is largely in part due to government
subsidies. For storable commodities such as corn, the government established a
target price based on the cost of production, and whenever the market price
dropped below that target, the farmer could either sell his corn to a weak
market, not make a lot of money, and weaken the market further, or he could sell
his crop to the government at the target price. While this program kept corn
prices from collapsing, it also meant that any farmer who produced corn (or
other crops with this program in place) did not have to abide by the rules of
supply and demand—they could always make money, whether it be from the market
or the government. (Pollan, 51-52)
But, supply and
demand are still at play, because due to this surplus of corn that infiltrates
almost all of the processed, packaged foods that we eat today, these products
are relatively inexpensive when compared to whole, fresh foods. This means that more people are buying the
foods, increasing its success in this environment. Also, because there is so much of it and it
is so cheap, we have now begun using it to feed our livestock. In fact, about
60 percent of America’s commodity corn goes to feeding livestock. (Pollan, 66)
“Corn found its way into the diet of animals that never used to eat very much
of it (like cattle) or any corn at all, like the farmed salmon now being bred
to tolerate grain.” (Pollan, 67) Cows are ruminants, which means that they
evolved to eat grass. Fattening up a cow, however, takes much less time and
money if it is fed a grain (like corn). Cheap
and quick are both things our current food market demands. This type of feeding
explains why wild animals have a lower saturated fat content than do today’s
farmed animals; they are eating grass and gaining weight gradually, not eating
grains and gaining it so quickly.
So, because
convenience, taste, and inexpensive cost are all desirable traits for the food
humans want to eat, this is the type of food that has evolved and done well in
this current environment. “Over production is a longstanding characteristic of
U.S. agriculture. Technology—and
therefore efficiency—has long outpaced population growth, and government
programs to cope with the problem have often made it worse. Yet the size of America’s waistline was
relatively stable until around 1980. In
the past 20 years, though, the proportion of Americans who are obese has
swelled to 31 percent; another 34% are merely fat.” (Akst) So even though the food itself is doing well,
and technically increasing human’s fitness levels (which is presumably why it
was selected for) it is having a lot of unintended consequences on our health,
and our societies. Cordain, et al
explains that because humans ate the same way for almost 200,000 years, our
genome became accustomed to that pre-agricultural diet. Then, “when permanent environmental changes
occur[ed] in [the] population, individuals bearing the previous average status
quo genome experience evolutionary discordance…This evolutionary discordance
manifests itself phenotypically as disease, increased morbidity and mortality,
and reduced reproductive success (341). They are suggesting that this type of
food is actually decreasing our fitness.
As we saw
previously with the rise agriculture, it seems that humans tend to select foods
based on the foods’ ability to increase humans’ fitness levels, so a new way of
eating has recently sprung up. Because
it is now possibly the case that healthier, lower
calorie foods will increase our fitness, locally grown and organic foods, particularly
produce, are beginning to thrive (Hurst). This is known as the Green
Revolution, and is perhaps in an effort to mimic humans’ previous eating
patterns. Much of America is still in
the packaged, processed stage of this food story, but all around us we are
beginning to see a shift towards “all natural” and “fresh” foods. As this is
still a relatively new type of eating, it is hard to say whether this type of
food will become more successful still, or slowly die out in competition with
the packaged food, which is still propagating itself very successfully. Perhaps they will co-evolve, and become
dependent on each other, or perhaps a new way of eating will come in to fill a
niche, and take over altogether.
Whatever it is
that is going on in our world, though, there will always be a food there to
fill the requirements of how we want to eat, whether it be quickly or healthily
or by spending all day gathering. It has been shown that food is very adaptive
to its environment (which is human eating patterns), and as long as humans have
control over the food we produce, it will continue to adapt to our needs
accordingly.
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