Reading Health in Ancient Bones
You cannot interview a Neolithic farmer about their health. You can, however, read what time and disease wrote into their bones. The field of paleopathology, the study of disease in ancient remains, has accumulated decades of skeletal evidence that tells a surprisingly coherent story about what the agricultural revolution did to human health. The most comprehensive synthesis comes from biological anthropologist Clark Spencer Larsen, whose work examining skeletal collections from the Americas and Europe across the pre- and post-agricultural transition has become a foundational reference in the evolutionary medicine literature.
Several skeletal findings appear consistently across independent studies from different regions of the world. First, average stature declined at the Neolithic transition. In European populations, average male height dropped by approximately 3-6 cm after the introduction of farming, a reduction attributed to nutritional narrowing as diverse wild diets were replaced by calorie-dense but micronutrient-poor cereal grains. Height only returned to pre-agricultural levels in parts of Europe within the last century. Second, dental caries exploded: in pre-agricultural skeletal populations, caries affect roughly 1-5% of teeth. In early agricultural populations, rates of 20-40% are common, consistent with the sudden introduction of fermentable dietary carbohydrates from domesticated grains providing substrate for acid-producing oral bacteria.
Third, evidence of porotic hyperostosis and cribra orbitalia (abnormal bone texture in the skull indicating iron-deficiency anaemia) increases sharply at the agricultural transition. Fourth, infectious disease lesions in bone, evidence of tuberculosis, treponemal disease, and systemic bacterial infections, become dramatically more common in agricultural populations, consistent with the epidemiological shift produced by higher population density, animal domestication, and reduced movement between camps that had previously interrupted disease transmission cycles. The bones tell a clear story: agriculture was transformative for civilisation and costly for individual human biology in several specific and measurable ways.
The Tsimane: The World's Healthiest Arteries
The most compelling modern evidence for hunter-gatherer health advantages comes from a study of the Tsimane, a forager-horticulturalist population of approximately 16,000 people living in the Bolivian Amazon. Beginning in the early 2000s, anthropologists Michael Gurven at UC Santa Barbara and Hillard Kaplan began the Tsimane Health and Life History Project, one of the most comprehensive studies of health in a traditional population ever conducted. In 2017, cardiologists joined the project with portable CT scanners, examining coronary artery calcium (CAC) scores in 705 Tsimane adults aged 40-94.
The results were extraordinary. 85% of Tsimane had no detectable coronary artery disease by CT scan. Among those aged 75 and older, 65% still had no coronary plaque, a rate that would be essentially unprecedented in any Western clinical population of similar age. The CAC score of a typical 80-year-old Tsimane was equivalent to that of a 50-year-old American. The Tsimane diet is high in carbohydrates but these are low-glycaemic wild roots, plantains, and rice rather than refined products, accompanied by high-fibre intake, lean game, and river fish. Physical activity runs to approximately 6-7 hours of moderate intensity daily. Chronic psychosocial stress from financial precarity, traffic, social comparison, and schedule pressure does not exist in recognisable form.
The Tsimane are not without health burdens: they have high rates of intestinal parasites, respiratory infections, and dental disease, and their life expectancy at birth is much lower than in Western populations due to infection and injury. But their cardiovascular health in surviving adults is so dramatically superior to Western norms that it has forced a reassessment of what level of cardiovascular disease with age is biologically necessary, versus how much is environmentally created by the modern lifestyle. The answer appears to be: most of it is environmentally created, and it is not inevitable.
The Hadza and the Lost Microbiome
If the Tsimane illuminate cardiovascular health, the Hadza of northern Tanzania illuminate something equally important: the gut microbiome. The Hadza are one of the last remaining populations of near-pure hunter-gatherers on Earth, numbering roughly 1,200-1,500 people, subsisting almost entirely on hunted game, honey, baobab fruit, tubers, and berries. Tim Spector's collaboration with Jeff Leach and Stephanie Schnorr produced landmark gut microbiome analyses of Hadza fecal samples in 2014, published in Nature Communications.
The Hadza microbiome is approximately 40% more diverse than that of contemporary Western populations by standard diversity metrics. They harbour bacterial genera rarely or never detected in Westerners, including high abundances of Treponema species (commensal gut types, not the syphilis-causing pathogen), Prevotella, and various uncharacterised taxa. Their microbiome also shows striking seasonal variation, reflecting dramatic shifts in available food between dry and wet seasons, a pattern completely absent in Western populations who eat essentially the same foods year-round. This seasonal cycling of the microbiome may be functionally important: it exposes the immune system to different antigenic challenges throughout the year in a way that modern industrialised diets eliminate entirely.
This microbiome diversity has potential health implications across multiple domains. As explored in our article on the gut microbiome and personalised medicine, microbial diversity is associated with lower rates of allergy, autoimmune disease, inflammatory bowel disease, obesity, and metabolic syndrome. The Hadza and similar traditional populations have extremely low rates of these conditions. The magnitude of microbiome impoverishment in Western populations, estimated at a loss of roughly 30-40% of ancestral diversity in the past century, is increasingly recognised as a potential driver of the modern chronic disease epidemic rather than merely a correlate of it.
Ancient Arteries and the Horus Study
A recurring assumption in cardiology was that atherosclerosis is an inevitable consequence of ageing: a biological process that would occur in any sufficiently long-lived human regardless of diet or lifestyle. This assumption was significantly challenged by the Horus study, published in The Lancet in 2013, in which cardiologists and radiologists performed CT scans on 137 mummies from four ancient populations spanning 4,000 years: ancient Egyptians, Peruvian Incas, Ancestral Puebloans of the American southwest, and Unangan hunter-gatherers from Alaska.
Arterial calcification was present in mummies across all four populations, including the Unangan hunter-gatherers who ate primarily marine mammals and fish. This finding was initially interpreted as evidence that atherosclerosis is universal and lifestyle-independent. However, subsequent analyses found that calcification rates were considerably lower in the non-agricultural Unangan population than in the agricultural ones, and that the overall prevalence and severity in all pre-industrial populations was dramatically lower than in modern Western populations matched for estimated age. The finding is consistent with the Tsimane cardiovascular data: some arterial change may accompany ageing in any long-lived human, but the extreme rates seen in modern industrial populations represent a pathological amplification of a much milder baseline process.
The practical implication is that the cardiovascular disease burden in modern populations is not a price of living longer or an unfortunate biological inevitability. It is, to a substantial degree, a consequence of specific environmental mismatches that are in principle addressable. The debate over which mismatches matter most, and in what relative proportion, continues in evolutionary medicine. But the direction of the evidence is clear: the modern Western environment amplifies a baseline ageing process into a disease epidemic of enormous proportions.
Lieberman's Mismatch Disease Framework
Daniel Lieberman at Harvard University has articulated the most comprehensive evolutionary framework for understanding modern chronic disease. Lieberman argues that most chronic diseases plaguing modern populations are "mismatch diseases": conditions that arise because our Stone Age bodies are being used in conditions radically different from those in which they evolved. The human genome was essentially finalised in its current form roughly 200,000-300,000 years ago, with only minor modifications since. The agricultural revolution began approximately 10,000 years ago, and the industrial revolution transformed most people's lives within the last 200 years. Evolution has not had time to catch up.
Lieberman identifies specific mismatches with major health consequences. Our bodies evolved to crave sugar and fat because these were scarce caloric resources in the ancestral environment, a preference that maximised survival when sugary fruit and fatty game were rare windfalls but becomes pathological when surrounded by unlimited cheap processed food. Our immune systems evolved in environments teeming with parasites and diverse microbes, and their calibration may depend on this microbial exposure. Its absence in ultra-hygienic modern environments may be driving the epidemic of allergic and autoimmune conditions, what Graham Rook reformulated as the old friends hypothesis: our immune systems need specific ancient microbial exposures to maintain healthy regulatory function.
The mismatch framework has direct implications for how we approach prevention and treatment. Rather than asking only "what drug can we give?" it asks "what environmental input are we missing, or what are we overexposed to, that is driving this condition?" This is the foundational question of quantum and evolutionary medicine, and it sits at the heart of the approach taken at QuanMed AI. Our article on what is quantum medicine explores how this evolutionary mismatch perspective integrates with biophysics and systems biology to form a more complete model of human health than either conventional medicine or simplistic evolutionary nostalgia can provide alone.
Sleep in Traditional Populations
One of the most striking windows into ancestral health comes from sleep research in traditional populations. Jerome Siegel at UCLA conducted actigraphy studies of three pre-industrial groups: the Hadza, the San Bushmen of Namibia, and the Tsimane. Published in Current Biology in 2015, the findings overturned several assumptions in sleep medicine. Average sleep duration across all three groups was 6.0-7.1 hours, substantially less than the 8-9 hours often cited in modern guidelines, but sleep quality (as measured by sleep efficiency and continuity) was significantly higher than in age-matched Westerners.
Crucially, all three populations showed a consistent pattern of falling asleep several hours after sunset and waking before or shortly after sunrise, with bedtime strongly tracking ambient temperature decline rather than light. None of the traditional populations had anything resembling insomnia in the clinical sense. Sleep onset was rapid (typically within minutes), awakenings were rare, and there was no evidence of the chronic sleep debt that characterises modern populations. Siegel's interpretation was that insomnia and fragmented sleep are primarily diseases of modernity, driven by artificial light disrupting circadian rhythms, sedentary lifestyles that reduce homeostatic sleep pressure buildup, and chronic psychological stressors that maintain hyperarousal into the night hours.
The traditional population sleep data is among the most actionable findings for modern health optimisation. It suggests that the key variables are not total sleep duration but sleep timing aligned with the natural light-dark cycle, sleep quality without artificial light disruption, and physical activity levels that build adequate sleep pressure by bedtime. These are individually modifiable in a modern environment, unlike many other aspects of the ancestral lifestyle that cannot be practically recreated. The convergence of traditional population evidence with chronobiology and Blue Zone longevity research points consistently toward the same small set of behaviours as the highest-leverage interventions for extending both lifespan and healthspan.
Practical Lessons from the Ancestral Baseline
The evolutionary medicine perspective does not call for a literal return to hunter-gatherer life. Most people have no desire to forage for tubers or sleep on the ground, and the modern world offers genuine advantages in safety, medicine, and opportunity that no serious person would trade away. What evolutionary medicine offers is a calibration tool: by understanding what our physiology evolved to expect, we can identify the most important mismatches and selectively address them within a modern context.
The highest-leverage ancestral mismatches to address in contemporary life, based on convergent evidence from paleopathology, traditional population research, and evolutionary biology, are: dietary diversity (eating dozens of different plant species weekly rather than a narrow range of processed foods, prioritising fibre and fermented foods for microbiome diversity), physical activity variety (walking, lifting, squatting, carrying in natural contexts, not only cardiovascular equipment), sleep timing (consistent bedtime and wake time aligned with natural light, darkness before bed), microbiome inputs (fermented foods, dietary fibre diversity, reduced antibiotic exposure, outdoor time with natural soil and plant exposure), and social connection (stable, reciprocal, multi-generational social bonds that all traditional populations share and that appear to be among the strongest predictors of longevity in every population studied).
The diseases killing and disabling most people in industrialised countries today were largely absent from the human experience for most of our species' history. That is not primarily because our ancestors died too young to develop them (many did not, as the Tsimane and paleopathological evidence demonstrates). It is the result of a profound environmental mismatch that has accumulated over a very short evolutionary time window. Closing the most important of those gaps, using modern knowledge and modern tools to give our Stone Age bodies something closer to the conditions they evolved in, is the most powerful preventive medicine framework available. Understanding where we came from is the first step in understanding where our health can go.
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