On Monday, March 10, the EvoS Club, Student Association and the College of Liberal Arts and Sciences hosted a talk by assistant professor in the Department of Anthropology Ken Nystrom on diet and human evolution regarding the scientific reasons behind what we as a species have progressed to eat.
The lecture, titled “From Ardipithecus to Agriculture: The Science of Diet and Human Evolution,” was conceptualized in response to recent increased public awareness of the nature of the industrialized food complex and health consequences, like obesity, typically associated with a “westernized” diet as well as the considerable amount of discussion in popular media regarding ancestral diets such as diet-trend books that advertise Paleolithic Era or “caveman” dietary habits.
Nystrom’s talk was derived from the material taught in his class “The Bio-Archeology of Food,” where students learn both how and why anthropologists reconstruct evolutionary diet. Nystrom prefaced the discussion, noting that many students’ interest in the class derived from the desire to learn “what I should be eating,” to which he said no particular diet could be characterized as the “right” diet a specific individual should follow.
“One of the features of humans is that we have an incredibly plastic ability – we can respond behaviorally, physiologically [to] adapt very well to a very wide range of environmental circumstances and to a very wide range of diet,” Nystrom said.
According to Nystrom, food is intimately linked with social organization and hierarchy, which in turn are impacted by the resource subsistence patterns of a species – in the case of humans, our development from a food foraging group to a food producing group. Nystrom explained the evolutionary change as having been made possible from cephalization, the concentration of nerve tissue, resulting from a significant increase in human cranial capacity in Homo ergaster, a chronospecies of Homo erectus.
According to Nystrom, there is only one explanation for this rapid physiological development – a change in diet.
“Brains are a very expensive organ that require a lot of energy, so we have to find that energy from somewhere else,” Nystrom said. “There is very good evidence for meat consumption [by Homo ergaster] in the form of human-made cut marks on bone.”
Nystrom said this discovery indicates that humans gained primary access to meat before they were known to use tools – not as a secondary savager, but as a power savager, one who is able to scare off the predator who made the kill.
“It wouldn’t take a lot of meat to be included into the diet to have a significant impact on human evolution,” Nystrom said.
Nystrom said the first instances of humans evolving from food foragers to food producers was during the Neolithic Revolution in the geographic region known as the Fertile Crescent, where Iraq and Iran stand presently. Nystrom said around this time exists evidence of both plant and animal domestication.
Nystrom explained that despite certain survival risks initially present in food producing groups compared to food foraging groups such as increased exposure to disease vectors via the domesticated animals and plants, a species longevity in terms of reproductive fitness stands to benefit if successful. As to why humans made the switch to agriculture, Nystrom shared two theories: first, humans were “pushed” into agriculture out of necessity due to population growth and insufficient resources or second, humans were “pulled” into agriculture by natural selection whereby an organism alters its environment to increase its chances of survival – more food allows for larger population.
“Instead of saying that agriculture is bad, which it is from a physiological perspective, from an evolutionary perspective and a Darwinian perspective, agriculture has been phenomenally successful as an adaption,” Nystrom said. “We have to combine perspectives in order to understand the evolutionary significance in changes in the human diet.”
When asked his opinion on modern diets, he responded, “Enjoy in moderation.”