The peoples the book draws on
What hunter-gatherers tell us about modern health
Much of the evidence behind evolutionary mismatch comes from a handful of foraging and traditional peoples. This page gathers what the book and its reference library say about them, one quoted sentence at a time, each linked to where it comes from.
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Who are they?
- Hadza
Hunter-gatherers of Tanzania, roughly 1,200 of them, the most-studied foraging population in this book. They are contemporaries rather than ancestors, and many now choose settled camps and villages. (Prologue)
- Tsimane
Forager-horticulturalists of the Bolivian Amazon, with the lowest coronary artery calcium reported anywhere. They also report chronic pain at industrialized rates, so this book uses them as evidence both ways.
- Ju/'hoansi
San hunter-gatherers of the Kalahari, also written !Kung, whose work diaries produced the idea of the original affluent society. Counting tool-making and housework, their weeks ran to about 40 hours for women and 45 for men.
- Turkana
Pastoralists of northwest Kenya who get about 62% of their calories from milk. In one large study no traditional Turkana met the criteria for obesity or metabolic syndrome.
- Kitava
An island in Papua New Guinea where a 1990 survey of 213 adults, by interview and resting ECG rather than autopsy or scan, found no case of stroke, sudden death or angina, although more than three-quarters of adults smoked.
- Yanomami
A people of Venezuela and Brazil whose systolic blood pressure showed no measurable rise with age, and whose sodium intake was the lowest in INTERSALT.
- Rarámuri
Also called Tarahumara, farmers and runners of Chihuahua, Mexico. Researchers working with them named the popular romance the "fallacy of the athletic savage": they get injured too, and mostly they walk.
- Dogon
Millet farmers of Mali whose menstrual huts let Beverly Strassmann count women's cycles. A Dogon woman who lived to menopause had a median of about 109 periods.
- Haenyeo
Women divers of Jeju, Korea. Before wetsuits arrived in 1977 their winter metabolic rate ran about 35% above the standard; within a few years of covering up, the adaptation was gone.
How do hunter-gatherers sleep?
Researchers once asked people in three foraging societies with no electric light to wear a small monitor on the wrist through the night: the Hadza of Tanzania, the San of Namibia and the Tsimane of Bolivia.
How active are hunter-gatherers?
The ancestral figures, such as the Tsimane's steps, show that the old signal was large; they do not show that you need to match it, and no trial has asked.
The Hadza rest as long as industrialized people do, so sitting alone cannot be the whole story.
Reference topic 6: The Sitting Disease, the skeptic's corner
Use the step and weekly-minute targets in Topic 40; the Tsimane pattern is hours of mostly light and moderate activity.
Reference topic 8: The Heart That Remembers the Savanna, graded recommendation
What are hunter-gatherers' hearts and arteries like?
When researchers came to scan their hearts, about sixteen thousand Tsimane lived along the Maniqui River, a tributary of the Amazon in lowland Bolivia.
Kitava's "absence" of heart disease rests on interviews and resting ECGs, not autopsies or scans; smoking intensity is unclear; and systolic pressure there still rose after 50.
Reference topic 8: The Heart That Remembers the Savanna, the skeptic's corner
More than nine in ten Tsimane and Moseten adults studied had calcified arteries inside the skull, a higher share than in comparable industrialized groups.
Reference topic 8: The Heart That Remembers the Savanna, the skeptic's corner
By a comparable one, so were about half of Tsimane adults, who have the lowest coronary artery calcium (calcium buildup in the heart's arteries) of any population yet measured (Topic 8).
Reference topic 17: The Water You Forgot to Drink, the skeptic's corner
It is ancient, found in mummies, yet 85% of Tsimane adults scanned had no coronary calcium at all.
Do hunter-gatherers get chronic pain?
The Tsimane of Bolivia, a non-industrialized people, report current pain, most often in the back, 1.7 to 8.2 times as often as comparison groups in Asia and Australia, after allowing for age.
In the Tsimane language, they asked 388 people aged 10 to 75 whether they hurt in the back (murujru), arm, hand, leg or foot.
Reference topic 21: The Pain You Were Not Supposed to Keep, opening
If lasting pain were a disease of desks and sofas, the Tsimane should have been spared it.
Reference topic 21: The Pain You Were Not Supposed to Keep, opening
The Tsimane data are self-reported, questionnaires and norms for admitting pain differ between studies, and the current-pain comparisons were mostly with non-industrial or middle-income countries.
Reference topic 21: The Pain You Were Not Supposed to Keep, the skeptic's corner
Williams's inactivity hypothesis sits awkwardly with Tsimane who work through pain and still hurt; too much load and too little movement may both matter.
Reference topic 21: The Pain You Were Not Supposed to Keep, the skeptic's corner
How do hunter-gatherers age, and how long do they live?
Among Tsimane aged sixty and over, about one in a hundred had dementia; among their neighbors the Moseten, fewer still.
Tsimane brains shrink with age, as brains do everywhere, but more slowly than American and European brains, in bodies whose blood carries the marks of constant infection and inflammation.
Life expectancy at birth barely moved, from 24.6 years among the foragers to 25.5 among the farmers.
Reference topic 4: The Last Ice Age and the Birth of Agriculture, the skeptic's corner
In 2014 and 2015, 705 Tsimane men and women aged 40 and over left their villages in the Bolivian Amazon to lie, one at a time, inside a CT scanner in the city of Trinidad.
Reference topic 8: The Heart That Remembers the Savanna, opening
Longer lives; earlier menarche, fewer and later births and shorter breastfeeding (three to four times the Dogon's menstrual cycles); excess body fat; tobacco and alcohol.
Reference topic 22: Cancer in a New Environment, mismatch card
What do hunter-gatherers eat, and what does it do to them?
Chewing tough food wore foragers' front teeth down until, by young adulthood, they met edge to edge.
Ehrlich recalls the Stanford paleoanthropologist Richard Klein telling him, "I've never seen a hunter-gatherer skull with crooked teeth."
Reference topic 16: The Shrinking Face, the skeptic's corner
For seven weeks they lived as hunter-gatherers, eating what the country gave them.
More that the book and library say about them
The forager data come from small groups studied for weeks.
Off the Korean island of Jeju, women called haenyeo have dived for shellfish and seaweed for centuries, and until wetsuits arrived they did it through the winter in suits of thin cotton.
What survives in the oldest haenyeo fits the story: they keep some cold tolerance in the face and hands, the parts a wetsuit leaves bare.
Cold acclimatization fades within a few years of the signal stopping, as the haenyeo showed, though the metabolic cost appears small, and a body that rarely meets heat has had no practice at shedding it.
The hunter-in-the-classroom evidence rests on one gene study, one online game and one natural experiment in diagnosis rates, and none of it shows ADHD traits helped most ancient foragers.
Every night for two years in the late 1980s, the anthropologist Beverly Strassmann noted which women were sleeping at the two menstrual huts of Sangui, a village of Dogon millet farmers in Mali, where custom sent women during their periods.
Book, Chapter 15: Women's Bodies Across the Life Course, opening
The Tsimane data are cross-sectional snapshots of a small, selected population, and one finding cuts against any tidy story: carriers of APOE4, the gene variant most linked to Alzheimer's in industrialized countries, had better-preserved thinking when their parasite load was high.
Travis Pickering and Henry Bunn argued that the tactic is rare in anthropologists' accounts of foragers and confined to very open, very hot habitats.
Over 20 years and well over 100 successful Hadza bow hunts, they wrote, "we have never observed persistence hunting by the Hadza, nor have informant interviews revealed this as a strategy they practice."
Lieberman and colleagues replied that recent foragers, with bows, spear-throwers and nets, are poor stand-ins for early Homo, a trap they called "the tyranny of ethnography."
The agricultural body: a forager's physiology, partly retuned since farming began.
Reference topic 4: The Last Ice Age and the Birth of Agriculture, mismatch card
There, a comparison of some 200 Natufian foragers with a similar number of Neolithic farmers found more infection after farming, less skull trauma in men and no change in joint disease: "a complex health profile."
Reference topic 4: The Last Ice Age and the Birth of Agriculture, the skeptic's corner
Foragers were not a disease-free baseline either.
Reference topic 4: The Last Ice Age and the Birth of Agriculture, the skeptic's corner
At Con Co Ngua, a settled forager site in northern Vietnam, about one person in seven had bone lesions consistent with hydatid disease, a tapeworm infection usually tied to herding.
Reference topic 4: The Last Ice Age and the Birth of Agriculture, the skeptic's corner
Foragers' leisure was also less ample than once claimed, as critics have argued since the early 1980s, although farming does seem to cost leisure.
Reference topic 4: The Last Ice Age and the Birth of Agriculture, the skeptic's corner
Among the Agta, hunter-gatherers in the Philippines, more time spent on non-foraging work, mostly farming, went with less leisure, an effect driven by women.
Reference topic 4: The Last Ice Age and the Birth of Agriculture, the skeptic's corner
What evolutionary mismatch means, and how a claim is tested · Every mismatch card in one table