Capítulo 4
Moses the Microbiologist: Ancient Wisdom in Public Health
The Agricultural Age was fundamentally shaped by religion. The Torah reveals remarkable insight into disease prevention through purification rituals. Hand washing-now recognized as one of the most effective disease prevention methods-was mandated after waking, after using the bathroom, before meals, and in numerous other situations. Even washing without soap provides significant protection. Similarly, Islam requires hand washing five times daily before prayer.
Bathing was another crucial purification ritual. On Yom Kippur, the high priest had to bathe before making offerings, emphasizing cleanliness before God. Jews have been avid bathers for millennia, finding opportunities at every turn-particularly on the Sabbath, when all Jews were required to undergo multiple purification rituals: bathing, hand washing, laundering clothes, and cleaning homes.
The Jewish people understood sterilization through fire and created "water of purification" (possibly an early soap) by combining water with ashes from sacrificial burning. When sacrificial slaughter ended, rabbis reinterpreted this as scalding hot water, leading Jews to sterilize dishes by submerging them in boiled water.
The laws recognized different materials required different treatment: porous earthenware pots had to be destroyed if contaminated, while bronze could be scoured and reused. The code acknowledged time's purifying power during quarantine, recognizing the body's ability to fight infection.
Military victories required extensive purification: quarantine, washing for soldiers who touched corpses, sterilizing metal plunder with fire, and washing captives (only virgins were spared, reducing STD transmission). Female captives had their heads shaved and nails trimmed-practices now known to eliminate hiding places for pathogens.
The Torah restricted sexual behaviors that increased disease risk, including prostitution, premarital sex, adultery, and other non-monogamous activities. These restrictions particularly benefited women, who bear greater health burdens from STDs. Jewish women historically have lower rates of cervical cancer (caused by HPV), likely due to these sexual practices.
Circumcision, God's covenant with the Jewish people, reduces urinary tract infections, STD transmission, and penile cancer. The Mosaic Law's hygiene code correctly identified infection sources (vermin, insects, corpses, bodily fluids, food, sexual contact) and prescribed effective disinfection methods.
When Jesus formed his splinter sect and abandoned hand washing before meals, he unwittingly set Christianity on a less hygienic path. As the Roman Empire fell and its sewers and aqueducts decayed, Christendom became filthy. The price was the Black Death, which killed a third of Europe's population. While Christians blamed Jews for the plague, the Jewish people may indeed have suffered less-not through conspiracy but through adherence to their brilliant hygiene code.
Ironically, when Dr. Ignaz Semmelweis "discovered" the importance of hand washing in the mid-nineteenth century, he was recognizing a practice Jews had followed for millennia, documented in Western civilization's most accessible text.
Capítulo 5
Pushing Human Limits: From Exploration to Space
The Industrial Revolution propelled humans into completely novel habitats-ones our ancestors had never experienced during eons of genetic and cultural evolution. From hot air balloons reaching unprecedented altitudes to submarines exploring ocean depths, explorers pushed the human body in ways it had never been pushed before, revealing both the limits of the human organism and the necessary conditions for human life.
In the Industrial Age, humans continued to discover our biological limitations by pushing into extreme environments. Decompression sickness ("the bends") first appeared in 1840 during underwater salvage operations and became common among industrial workers in compressed air environments. The term originated during Brooklyn Bridge construction in the 1870s, leaving hundreds with lifelong health problems.
The British were among the first to experience the health consequences of industrialized diets. Their early adoption of refined sugar led to widespread dental problems, earning them a reputation for poor teeth that persists today. Obesity also emerged, prompting William Banting to publish the first popular diet book in 1863.
Indoor living created new health challenges. Rickets, "the British Disease," first appeared among the wealthy who avoided sunlight and later spread to the urban poor. The condition, caused by vitamin D deficiency, was eventually addressed through milk fortification in the 1930s.
As exploration continued, humans reached new extremes. In 1953, Edmund Hillary and Tenzing Norgay conquered Mount Everest using supplemental oxygen systems. The Space Age followed, with the 1969 Moon landing representing the pinnacle of human exploration.
Long-duration spaceflight revealed that humans need habitats matching our evolutionary design. Habitat features fall into three categories: constants (gravity, atmospheric pressure), cyclicals (day/night, seasons), and variables (food, temperature, movement, social interaction). The key insight: organisms thrive in environments resembling their ancestral habitats.
Despite these challenges, humans have shown remarkable resilience in harsh environments. Dr. Peter Suedfeld calls us "Homo Invictus" (unconquerable humans), noting that survivors possess purpose and take action toward meaningful goals.
Capítulo 6
Biohacking: The Information Age Approach to Health
The Information Age dawned with Francis Crick and James Watson's discovery of DNA's double-helix structure in 1953, revealing the "secret of life." DNA's elegant simplicity-two mirror-image strands with just four molecules forming the basis of all life's code-was gradually sequenced, beginning with a tiny bacteriophage in 1977 and culminating in the human genome mapping in 2000. This achievement depended on computing advances, highlighting profound similarities between biology and computers: both use digital code, both can be "infected" by viruses, and both process information. As Bill Gates noted, biology is the original information technology-one that predates computers by eons.
Hackers-originally respected as hands-on virtuosos at MIT rather than digital criminals-embraced a philosophy that valued practical experimentation over theory, speed over perfection, and open systems over authority. Their ethos includes the Hands-On Imperative (learning by doing), embracing failure as learning, following the 80/20 rule, repurposing existing tools, valuing simplicity, and distrusting centralized authority. This approach extends beyond computers to understanding any complex system, including human health.
Biohackers apply hacker principles to human health, using gadgets and data to track everything from blood sugar to sleep cycles. But the core principle is taking personal responsibility for one's health through self-experimentation. A smart biohacker examines diet across species (Animal Age), studies hunter-gatherer nutrition (Paleolithic), considers cultural adaptations (Agricultural), learns from industrial diet mistakes, and experiments to find personalized solutions. This trial-and-error approach mirrors evolution itself-as Nobel laureate Francois Jacob noted, "Nature is a tinkerer, not an engineer."
Throughout history, we've used technological metaphors to understand the body: fluid dynamics (humorism), hydraulic pumps (Freud's psychology), and combustion engines (metabolism). While these metaphors capture aspects of human biology, they're incomplete. The discovery of DNA revealed that information is the true essence of life. Watson and Crick's Nobel Prize recognized their discovery of "information transfer in living material." Our bodies aren't simple mechanical systems but sophisticated information processors with intricate feedback loops that maintain functionality despite constant threats. This information-based understanding helps us appreciate our evolutionary journey from primates to hunter-gatherers to herder-farmers to industrial consumers to biohackers.
Capítulo 7
Rethinking Food: Beyond Conventional Wisdom
What constitutes a healthy diet? Contradictory advice bombards us from all directions, with recommendations ranging from "eat as much meat as you want" to veganism, from no-carb to high-carb diets. The only consensus seems to be that fish is healthy and Twinkies aren't-though even this was questioned when a professor lost weight on a "Convenience Store Diet." "Everything in moderation" has become our coping mechanism amid this confusion, though it merely restates the problem rather than solving it.
Our dietary confusion contrasts sharply with the clarity surrounding our first nutrition: what mothers provide in the womb and through breast milk. Everyone respects the nutritional wisdom embedded in a mother's body during pregnancy. Similarly, breast milk is universally acknowledged as superior to formula-not because it's "low-fat" or "organic," but because it's biologically appropriate food humans are adapted to consume. The advice to breast-feed essentially means "eat like a mammal." It's only after weaning that dietary opinions diverge wildly.
The conventional wisdom to "eat fewer processed foods" is imprecise. Humans have been processing food for millennia-cooking, fermenting, tenderizing, even chewing are all forms of processing. What people actually mean by "processed foods" are industrial foods-those our great-grandparents wouldn't recognize, developed in laboratories and made in factories using novel technologies of the Industrial Age. This distinguishes them from Agricultural Age foods (grown on farms or ranches) and Paleolithic Age foods (hunted or gathered in the wild).
The term "whole foods" is another misnomer, standing in opposition to "processed" foods. A walk through Whole Foods reveals many items requiring processing, like bread and yogurt. What people really mean by "whole foods" are agricultural foods-what humans ate before the Industrial Age. Marketing images on food packaging reinforce this: idyllic farm scenes with red barns and smiling cows. Whole grains are farmer foods; whole milk is herder food. The advice to "eat more whole foods" actually means "eat more agricultural foods"-embracing a herder-farmer diet.
Many people equate "organic" with "healthy," though this isn't necessarily true-organic sugar is still sugar, organic cookies are still cookies. What "organic" really means is "not industrial." The organic movement distances itself from industrial ingredients and farming methods like chemical fertilizers, pesticides, and antibiotics. It's another rebellion against industrial food systems in favor of traditional agricultural diets.
The "calories in, calories out" approach oversimplifies weight management. Our bodies naturally match energy intake to expenditure, and satiation depends on more than just calories. The anti-fat consensus is relatively recent. Only in 1977 did guidelines promote higher carbohydrate and lower fat intake, yet farmers fatten livestock with carb-heavy grains-the very base of the human food pyramid.
Plants actually contain more chemical diversity and potential toxins than animals. Plants evolved biochemical warfare since they can't run away from predators, developing organic pesticides and poisons. Killing an animal is hard but digesting one is easy; killing a plant is easy but digesting one is hard. Our fear of animal fat rejects traditional herder diets like those of Mongolian nomads or American dairy farmers, who consumed nutrient-dense foods like raw milk, cream, butter, cheese, eggs, and meat. By rejecting these in favor of staple cereal grains, conventional advice essentially promotes eating "like a poor, malnourished farmer."
Capítulo 8
The Paleo Prescription: Four Principles for Optimal Health
Just as different hunter-gatherer tribes ate different diets, so too will "tribes" of modern people. Four general principles can establish a starting point for healthy eating: mimic a hunter-gatherer diet, follow ancient culinary traditions, avoid industrial foods and sugars, and make eating meaningful through experimentation and customization.
Eating a Paleolithic diet isn't about historical reenactment but mimicking the metabolic effects with supermarket foods. Stop counting calories-hunter-gatherers didn't count calories yet obesity was nonexistent among them. They pursued the highest-calorie, most nutrient-dense foods relative to effort required-usually large game and honey. A 2012 study of the Hadza tribe revealed their total energy expenditure was comparable to modern Americans, suggesting obesity stems from novel foods disrupting metabolism, not lack of activity.
Hunter-gatherers ate varied diets including meat, seafood, roots, vegetables, fruit, nuts, and eggs. Of 229 foraging societies studied, nearly three-quarters obtained more than 50% of calories from animals. Most Westerners would benefit from less carbohydrate and more fat. Many hunter-gatherer tribes consumed fat at levels equal to or higher than the standard American diet. After agriculture, the shift to higher carbohydrates caused widespread tooth decay, and today's excess sugar and carbs directly contribute to cardiovascular disease, insulin resistance, and diabetes.
Hunter-gatherers ate nearly every part of animals, with a preference for organs and fatty cuts over lean muscle meat. Brains, bone marrow, liver, heart, kidneys, skin, and tongue were all prized foods. Our aversion to nose-to-tail eating is largely cultural, similar to how sushi was once considered repulsive before gaining Western acceptance. Organ meats are exceptionally nutrient-rich. Liver appears as a nutritional powerhouse across cultures, while fatty deposits like bone marrow provide both energy and fat-soluble vitamins.
The key to plant consumption is maximizing nutrients while minimizing toxins. Eating diverse plants provides nutritional variety while reducing toxicity, as each plant contains different toxins that are generally harmless in small doses. The healthiest plant options include green leafy vegetables, seaweeds, fruits, berries, roots, and tubers-in contrast to grains, legumes, nuts, and seeds.
Hunter-gatherers didn't consume milk after infancy. Following animal domestication, certain herder populations developed genetic adaptations to digest lactose into adulthood-a trait now present in about 35% of the global population. Personal experimentation is recommended-eliminate dairy completely, then reintroduce it to observe how you feel. Many people do well with full-fat or fermented dairy like butter, heavy cream, sour cream, cheese, and yogurt.
Ancient culinary traditions exist for good reasons-they make food not just tastier but healthier. Scientists often discover that traditionally prized foods like seaweed and liver are rich in key micronutrients. Fermentation processes food using bacteria and appears in cuisines worldwide. It's applied to virtually every food group: grains (alcohol, bread), legumes (soy sauce), vegetables (pickles, sauerkraut), fruit (wine, vinegar), honey (mead), dairy (cheese, yogurt), fish (fish sauce), and meat (salami).
When lost in the wilderness, eating unknown berries can kill you, but nothing you eat will dramatically improve your health. The same principle applies at the grocery store: avoiding harmful foods matters more than adding healthy ones. Industrial foods (sugar, vegetable oils) and seed-based crops (cereal grains, legumes) act as slow poisons when consumed in large quantities.
Everyone is unique-with different genetics, formative experiences, gut bacteria, allergies, conditions, motivations, and constraints. Each person is a unique organism in a unique habitat requiring a unique diet. Beginners should start with a month of "orthodox" paleo free of industrial foods and agricultural newcomers, focusing on seafood, meat, vegetables, roots, tubers, eggs, and limited fruit and nuts. After establishing a healthy baseline, experiment by reintroducing foods one at a time to identify personal tolerances.
Capítulo 9
The Forgotten Power of Fasting
In wealthy nations, constant hunger has been replaced by incessant cravings. Most people rarely go without food for more than eight hours during sleep, and many can't even make it through the night without a snack. Continuous eating-"grazing" to "keep blood sugar up"-has become normalized, with hospitals even putting patients on glucose drips. But is constant feeding optimal?
Wild animals eat at intervals appropriate to their diet and ecology-herbivores almost constantly, carnivores sporadically. Many species naturally experience periods without food during hibernation, food scarcity, or illness. Captive animals often suffer when forced onto human feeding schedules-gorillas fed concentrated food early in the day developed regurgitation behaviors, while lions benefited from switching to a "gorge and fast" schedule that mimicked wild feeding patterns.
Hunter-gatherers don't follow the rigid "three square meals a day" pattern. Anthropological evidence shows they eat opportunistically based on food availability, spoilage concerns, and seasonal patterns. The !Kung Bushmen often skip breakfast entirely, with women gathering and sometimes eating berries throughout the day while men hunt. The most important meal typically follows the day's activities rather than preceding them. Hunter-gatherers regularly experience low-level hunger, eating when hungry, when food is ready, and when social norms permit-a stark contrast to our modern continuous feeding schedule.
During the Agricultural Age, purposeful abstention from food emerged in cultures worldwide. Religious fasts range from daytime abstention to multi-week commitments, with varying rules about what constitutes fasting. Judaism observes six annual fast days, with Yom Kippur requiring 25 hours without food or drink. Muslims fast from dawn to dusk during Ramadan. Catholics traditionally abstain from meat on specific days. Eastern Orthodox traditions include 174 fasting days annually with complex rules about forbidden foods.
Beyond spiritual purification, fasting offers substantial health benefits. When sick, animals naturally stop eating-a feature, not a bug. Fasting strategically weakens pathogens by cutting off their nutrient supply. Low-protein fasts deprive pathogens of essential amino acids and trigger autophagy-cellular "self-eating" that recycles cellular debris and destroys intracellular pathogens. Iron restriction during fasting impedes pathogen growth, as shown in studies of Kenyan children who had fewer acute infections when iron-deficient. Carbohydrate restriction starves glucose-dependent pathogens and even improves dental health by inhibiting Streptococcus mutans.
Fasting also shows promise in cancer treatment by activating cellular starvation defenses-healthy cells reduce division and focus on repair while cancer cells remain vulnerable. Studies show fasting before chemotherapy dramatically reduces side effects while maintaining or improving treatment effectiveness. Additionally, regular fasting improves metabolic health, with Mormons who fast monthly showing lower rates of coronary artery disease and diabetes.
Most people find breakfast essential because they're addicted to sugar. The typical American breakfast-cereal, milk, juice, toast-is a sugar bomb containing glucose, fructose, lactose, and sucrose. After a night without sugar, people wake in mild withdrawal, experiencing cravings and shakiness. Like smokers needing a morning cigarette, breakfast becomes a fix. Once adapted to fat metabolism, however, people can easily skip breakfast, with hunger pangs quickly subsiding and mental clarity improving.
Fasting affects men and women differently. For women, fasting signals resource scarcity, which can inhibit fertility-the body wisely prevents pregnancy during famine. Women who chronically restrict calories often lose their periods but regain fertility when adding back animal foods and fats. For beginners, sixteen-hour fasts appear sufficient to trigger autophagy benefits, with fasts up to twenty-four hours being safe for regular practice.
Capítulo 10
Movement as Medicine: Rediscovering Our Physical Nature
Until recently, humans needed to move constantly to survive. The Paraguayan Ache men hunt nearly daily, covering about six miles tracking and a mile in fast pursuit. Hunter-gatherer women walk extensively while carrying heavy loads, children, water, and food. Farmers toiled even harder, with chores beginning before sunrise and ending after sunset. But the Industrial Revolution replaced human power with machines, and the Information Revolution has created a world where success depends on sitting for decades of education and employment. The fundamental problem is that humans have lost their motivation to move.
Motivation literally means "a reason for physical motion." The most effective motivators tap into ancient human needs: hunger, fear, sex, status, community, and fun-all connected to survival and reproduction. Sports harness these tribal motivations effectively but become less accessible after college. In contrast, the fitness industry largely fails to motivate, as evidenced by the annual cycle of New Year's resolutions followed by abandoned gym memberships.
In 2007, I joined CrossFit-then a tiny fringe movement that has since exploded into a global fitness phenomenon. CrossFit's philosophy venerated the generalist rather than the specialist, combining high-intensity interval training, constant variation, and functional movements. But CrossFit's true revolution wasn't in exercise physiology but psychology-it completely redesigned the motivational habitat. Workouts were performed in groups, timed, scored, and never repeated. The environment was competitive yet cooperative, with strong camaraderie and no mirrors or fancy equipment.
CrossFit's design showed sophisticated understanding of human psychology, particularly masculine motivation. Workouts were competitive against the clock, oneself, and others. The group format created team-like camaraderie-the harder the workout, the stronger the bond. Though scalable to individual fitness levels, workouts remained challenging for everyone, creating a status hierarchy that attracted both elite athletes and average people wanting to associate with elite fitness.
Not everyone responds to competitive, high-intensity exercise. Lower-testosterone personalities often prefer activities like yoga, which creates an entirely different motivational habitat-quiet, egalitarian, and spiritual rather than competitive. Yet yoga still offers community and shared values while developing self-discipline. Dancing represents another ancient movement form that broadcasts health and sexual appeal while connecting to cultural traditions. Ultimately, finding meaningful physical activities matters more than optimal exercise protocols, as meaning drives consistent participation.
The future of fitness might be found in children's play. Unlike adults on treadmills, children naturally sprint, pivot, dodge, wrestle, climb and jump without instruction. This playful movement isn't frivolous but serves a biological function-preparing juveniles for adult challenges by practicing essential survival skills. Play is instinctual across species, from lion cubs to baby antelope, all rehearsing movements they'll need later in life.
Different species develop different play styles based on survival needs: predatory play for hunters, locomotor play for prey species, object play for manipulative species like humans, and social play for complex social species. These activities wire crucial neural pathways through practice. The gym of the future will be more like a jungle gym, focusing on skill development rather than just conditioning.
Capítulo 11
Designing Habitats for Human Flourishing
Jon Coe, an architecture student who visited Boston's Franklin Park Zoo, witnessed elephants chained and fighting in a small, dingy space. When he asked why they were chained, the keeper explained they were chained because they were fighting, and fighting because they were chained. This circular problem revealed the power of habitat design on behavior.
Coe pioneered a revolution in zoo architecture, challenging the conventional approach where famous architects designed impressive structures for human sensibilities rather than animal needs. His motto became "Nature is the model"-using natural materials like wood and dirt instead of concrete and steel, incorporating real plants native to animals' habitats.
This habitat-based approach applies equally to human health. Our habitats-physical environments, food choices, social circles, and cultural contexts-profoundly influence our development and decisions. Yet humans uniquely can modify our habitats through simple choices like different foods, joining motivating gyms, using standing desks, or installing circadian-friendly lighting.
The locavore movement emerged as a backlash against industrial farming, promoting food from local sources like farmers markets or backyard gardens. While offering benefits like community connection, fresher taste, and support for food entrepreneurs and heritage breeds, locavorism's scalability remains questionable.
The concept of "food miles"-measuring sustainability by distance traveled-proves deeply flawed when considering factors like climate suitability, soil fertility, fertilizer usage, and transportation efficiency. Large container ships move goods remarkably efficiently, making ocean shipping only a small percentage of food production resources.
Africa, with the most people engaged in local, small-scale organic farming, desperately needs agricultural productivity improvements to escape poverty. Historical agricultural advances enabled fewer farmers to feed more people, allowing urban development and eco-friendly living. Neither hunting-gathering nor purely organic agriculture can realistically feed today's global population.
The "pre-industrial" approach either becomes a luxury for the wealthy (like medieval royal hunting grounds) or requires dramatic population reduction-revealing the misanthropic undertones in some environmental thinking. While reducing consumption brings short-term environmental gains, simply using "less stuff" within our current paradigm cannot sufficiently reduce humanity's ecological footprint while allowing human flourishing.
The path forward isn't backward-looking but future-focused. We need innovation and creation rather than shrinking. Once people reach material prosperity, they care about environmental quality. Population growth will peak within decades, with countries like Japan already facing population decline issues.
The Information Age offers hope as we learn to hack biology-growing organs from stem cells, developing gene therapies, creating cyborgs with cochlear implants and mind-controlled prosthetics, and engineering bacteria for energy production. Though not all changes will be beneficial, our design solutions should use nature as a model.
We should take an "all of the above" approach to food systems, preserving traditional ways while addressing industrial problems. We need advocates for hunting, traditional farming, and responsible industrial agriculture, plus wise application of Information Age technology. As Stewart Brand said, "We are as gods and have to get good at it."
Humanity's uniqueness lies in our capacity for culture, technology, exploration and creation. Our challenge requires both conservation of Earth's habitats and risk-taking as we push beyond Earth. Like our ancestors, we must take small steps forward-"one foot firmly planted on the ground of what we are, the other reaching into the future of what we can become."
