Studies reveal how climate has driven 7,000 years of dietary change

Elevation of the highlands of the Central Andes. Pastoral animals, including alpaca, made up most of Highlander’s diet. Credit: Kurt Wilson

What a person eats affects his or her health, longevity, and world experience. Identifying the factors that determine a person’s diet is important for answering larger questions, such as how climate changes affect unequal access to favorable foods.

A new study, led by anthropologists at the University of Utah, provides a blueprint for systematically unraveling and assessing both climate and population size forces on different diets across the region in the past.

The authors recorded that climate had the greatest impact on diet in the Central Andes 400 to 7,000 years ago. This makes sense. Climate determines the resources available to people in the area. Researchers were surprised that the size of the population had little effect on dietary changes.

The exception was during the late horizon (~ 480-418 yBP), where the diets across the region became more similar to each other. This is in line with the Inca Empire, which appears to have centralized enough political power to reduce local dietary decisions, thereby weakening the effects of climate. This study provides a framework for investigating the relative role of climate and other socio-demographic factors on dietary changes over time, including in the future.

Curt Wilson, lead author and postdoctoral fellow at the University of Utah, said: ..

A study published in the journal on Monday, February 7, 2022 Scientific Reports..

The breathtaking terrain of the Central Andes extends from the surface of the sea to the highest mountains in the world. At each altitude, climate and food resources are very different. Coastal communities were primarily dependent on marine resources, with some agriculture. Medium-elevation societies had access to some marine resources and raised livestock such as llamas, but were primarily dependent on agriculture. The highland diet consisted of several farms, but idyllic animals were the mainstream.

Climate has brought about 7,000 years of dietary change

Paracas National Reserve on the coast of the Squid region of Peru. Credit: Edubucher via Wikimedia

The history of the region’s vitality is as violently rippling as landscapes, with complex societies moving up and down at various times. Population changes can affect socio-political complexity and change movement patterns, both of which affect diet.

“I’m really interested in the emergence of material inequality. If there are people who eat different things based on their status, then there is your inequality,” Wilson said. “The situation and inequality could not be compared directly with the available data, so” how socio-political complexity can affect food availability. Can you make a rough estimate? “

To do so, the author edited the largest dataset of past diets based on carbon (δ).13C ‰) and nitrogen (δ)15N ‰) North and South American isotope values ​​for the last 7,000 years. Stable isotopes derived from human bone collagen represent an individual’s lifetime average diet and abundance composed of various broad categories of plants (carbon) and animals (nitrogen).

Using published data, researchers have identified 1,767 individuals from published literature at the remains of Lake Titicaca, northern Chile, Peru. They used model simulations of average annual precipitation, average annual temperature, average annual seasonal temperature, and average annual precipitation seasonality for each individual location to generate regional climate variability. They also use a “date as data” approach to generate an estimate of the population size of each individual and process the number of sites dated at one time on behalf of the relative population size. , Edited about 4,000 radiocarbon ages.

Brian Coding, an associate professor of anthropology at the University of Utah and the last author of this study, said: Wilson led a team of all co-authors, undergraduate researchers, to help put together these findings. “Giving everything together access is a good example of where archeology is heading, answering big questions and making science open and reproducible.”

They compared dietary trends over time across three elevation categories: coastal, mid-elevation, and high-altitude. This allowed us to understand the amount of food explained by population changes and the local climate. This may be due to other social factors.

The findings showed that for most of the 7,000 years of study, there was little dietary overlap between the carbon and nitrogen isotope regions. However, most of that variation collapses on the late horizon (~ 480-418 yBP), where the Inca Empire dominated the region.

Climate has brought about 7,000 years of dietary change

Mid-elevation landscape of the Central Andes. Credit: Kurt Wilson

Even in the middle horizon (~ 1,350-950 yBP), it is a time of political centralization, carbon For coastal and mid-elevation individuals. During this time, both the Tiwanaku and Wari Empires engaged in regional trade and resettlement, contributing to the expansion of maize as an important component of the feast. Nevertheless, the characteristics of nitrogen remain clear in the elevation zone, environment Continued to dominate the diet.

“Even when we are politically centralized, people still rely heavily on their locals. Then, on the late horizon, the data suddenly strongly suggest that this disappears. “I will.” Wilson said. “The impact of the Inca Empire has overturned the impact of the region’s climate. diet In a way that the Wari and Tiwanaku empires couldn’t. “

This study details how most of the differences in people’s diets, which are an important part of the daily life of the Central Andes, were attributed to different climates. It also suggests that social processes can negate the effects of climate during the most socio-political interrelated periods. The author then adds data on the amount of socio-political impact each individual may have experienced. This can reveal invisible patterns of how inequality interacts with climate to affect daily life.

Researchers can apply these methods to other regions to determine how much climate Population changes have changed the diets of people in human history.

“What people eat and how they get it is a lot of a person’s daily experience,” Wilson said. “Understanding the causes of changes in these behaviors in the past is important for understanding how we can respond to future changes.”

Co-authors of this study include Weston McCool, Simon Brewer, Nicole Zamora-Wilson, Percy Schryver, Roxanne Lois Lamson, Ashlyn Huggard, and Joan Brenner Coltrain of the University of Utah. Daniel Contreras of the University of Florida.

Superfoods that fueled the ancient Andes through the turmoil of 2,500 years

For more information:
Kurt M. Wilson et al, Climate and Demography, is driving a 7,000-year dietary change in the Central Andes. Scientific Reports (2022). DOI: 10.1038 / s41598-022-05774-y

Provided by
University of Utah

Quote: Studies reveal how climate has driven a 7,000-year dietary change (February 8, 2022).

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Studies reveal how climate has driven 7,000 years of dietary change

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