Since the need to eat is one of the few true human universals, anthropologists have studied subsistence systems from a variety of perspectives. One way to think about the importance of food for human populations is to consider the number of calories an individual must obtain every day in order to survive. Anthropologists use the term carrying capacity to quantify the number of calories that can be extracted from a particular unit of land to support a human population. In his 1798 publication An Essay on the Principle of Population, Thomas Malthus argued, “the power of population is indefinitely greater than the power in the earth to produce subsistence for man.”1 He suggested that human populations grow at an exponential rate, meaning the population climbs at a rate that is constantly increasing. However, the availability of resources in the environment increases at only an arithmetic rate, which means that left unchecked human populations would soon outstrip the environment’s ability to provide sustenance. Malthus famously argued that war, famine, and disease were “good” or at least “functional” in the sense that they kept populations from growing too large.
While Malthus presented a grim view of humanity’s future, research suggests that the rate of human population growth, currently about one percent per year, is actually slowing. It is also not necessarily true that population growth has an entirely negative impact on human communities. The Danish economist Ester Boserup, for example, argued that human history reveals a connection between population growth and cultural innovation, particularly innovation in farming techniques. Because necessity is the mother of invention, she reasoned, the pressure of having more mouths to feed could be the dynamic that drives societies to develop new solutions.2
Modern anthropological studies of subsistence systems draw on insights and perspectives from several different fields, including biology, chemistry, and ecology, as well as a range of ethnographic techniques. This interdisciplinary perspective allows for cross-cultural comparison of human diets. In several decades of anthropological research on subsistence systems, anthropologists have observed that the quest for food affects almost every aspect of daily life. For instance, every person plays a role in society as a producer, distributor, or consumer of food. In the journey of a fish from the sea to the plate, for instance, we can see that in some societies, the same person can fill more than one of those roles, while in other societies there is more specialization. In a small fishing village, the same person might catch the fish, distribute some extra to friends and family, and then consume the bounty that same day. In a city, the consumer of the fish at a fancy restaurant is not the same person who caught the fish. In fact, that person almost certainly has no knowledge of who caught, cleaned, distributed, and prepared the fish he or she is consuming. The web of social connections that we can trace through subsistence provide a very particular kind of anthropological insight into how societies function at their most basic level.