Dense Worlds, Fragile Lives: Comparing Population, Diet, and Disease in the Maya Lowlands versus the Roman Heartland

 by Mary Harrsch © 2025

This morning I was astounded when I read this news release by Archaeology Magazine saying new LiDAR studies reveal an estimated 16 million Maya may have occupied 36,700 square miles of the Maya Lowlands—an area that comprises parts of Mexico, Guatemala, and Belize—during the Late Classic period (600–900 CE).

https://archaeology.org/news/2025/08/11/new-research-suggests-maya-population-may-have-topped-16-million/

In my paper, "Blood and Ash: Human sacrifice as a response to ecological catastrophe in the ancient Americas" I had compared juvenile mortality of Rome and the Maya then discussed sanitation issues and water management strategies of the two cultures to account for the difference between Rome's juvenile mortality of 30-35% and the Maya's at 35-50%. But, I did not explore differences in population density.

The central plaza of Teotihuacan on the left and Pompeii's forum on the right.
Extreme Densities, Different Worlds

Teotihuacan image courtesy of Wikimedia Commons contributor MikHeil. Pompeii forum image courtesy of Wikimedia Commons contributor Commonists.

So, I asked ChatGPT to calculate the population density of 36,700 square miles of the Roman Empire using the city of Rome as the center. It found the Maya may have supported roughly six times the population of the Roman heartland—approximately 16 million versus 2.5 million. Despite Roman juvenile mortality being roughly 15% lower, the Maya’s ability to maintain relatively low mortality is remarkable given their extreme population density.

With ChatGPT's help I revisited the differences in juvenile mortality as revealed in indicators such as differences in trade networks, presence of epidemic pathogens and agricultural practices and diet:

Comparative Schematic: Maya Lowlands vs. Roman Heartland (~36,700 sq miles)

Feature	Maya Lowlands	Roman Heartland (~108 mi radius around Rome)	Notes / Impact
Population	~16,000,000	~2,500,000	Maya ~6× higher within same area
Population Density	~436 people/sq mile	~68 people/sq mile	Reflects intensive local agriculture + settlement clustering vs. more extensive Roman land use
Agricultural Productivity / Diet	Intensive maize-bean-squash polyculture; under ecological stress, supplemented with ramón nuts, cassava (manioc), Amaranthus cruentus (amaranth)	Extensive grain and pastoral farming; heavily reliant on imported wheat from Egypt, North Africa, and Sicily	Maya could sustain high density locally; Roman density dependent on long-distance supply chains; diet quality declined under droughts for Maya
Settlement Pattern	Core-periphery structure with dispersed compounds; elite separation	Urban centers (Rome) with dense insulae, surrounding villas and farmland	Stratification moderates mortality but doesn’t drive density
Sanitation / Water Management	Some elite cisterns with filtered water; generally minimal for non-elite populations	Aqueducts, sewers, public baths	Romans had systematic infrastructure reducing waterborne disease risk; Maya had localized mitigation but not widespread
Pathogen Exposure	Low; geographic isolation and limited trade networks minimized introduction of epidemic diseases	High; extensive long-distance trade (as far as China) introduced epidemic pathogens	Isolation helped Maya maintain dense populations with moderate mortality
Mortality (Juvenile/Infant)	35–50%	~30–35%	Despite lack of Roman-style infrastructure, isolation and localized water/nutrition strategies moderated mortality
Ecological Stress	Megadroughts, volcanic impact; diet deterioration under stress	Generally stable; some localized droughts or floods	Maya droughts periodically increased mortality and reduced diet quality

Despite comparable local population densities, the Maya Lowlands and the Roman heartland differed dramatically in both ecology and diet. Within a 36,700 sq mile area, the Maya may have supported roughly six times the population of the Roman heartland—approximately 16 million versus 2.5 million. This high Maya density was made possible by intensive agricultural practices, including terracing, raised fields, and maize-bean-squash polyculture, which produced a high-calorie, protein-adequate diet. In contrast, Roman populations relied heavily on cereal grains and, critically, on large-scale imports of wheat from Egypt, North Africa, and Sicily, leaving them vulnerable to supply disruptions.

Under ecological stress such as megadroughts or soil depletion, Maya diets deteriorated over time as they substituted drought-resistant but nutritionally inferior foods like ramón nuts, cassava (manioc), and Amaranthus cruentus (amaranth) for maize, resulting in lower protein intake, fewer essential amino acids, and reduced caloric density. 

Settlement patterns also played a role in moderating disease exposure: Maya cities featured core-periphery arrangements with dispersed residential compounds, while Roman urban centers had dense insulae and surrounding villas. 

Critically, the Maya were relatively isolated from Old World pathogens due to limited trade networks, whereas Rome’s far-reaching commerce—even extending as far as China—regularly introduced epidemic pathogens. 

Together, these factors help explain how the Maya sustained extreme local density with juvenile mortality estimated between 35–50%, only about 15% higher than the Roman heartland, despite lacking aqueducts and large-scale sanitation systems.

This comparison highlights how population density, trade networks, and ecological stress shaped ancient societies in ways that continue to inform our understanding of population resilience and vulnerability today

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