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" Everyone helps everybody. Mothers help one another forage, process food, and take care of one another’s children. Fathers help one another hunt, share the spoils of their successes, and work together to build shelters, defend resources, and more. These and other forms of cooperation, however, require complex cognitive skills beyond those of apes. To cooperate effectively one needs a good theory of mind (to intuit what another person is thinking), the ability to communicate through language, the faculty to reason, and an ability to suppress one’s urges. Hunting and gathering also requires good memory to remember where and when to find different foods, as well as a naturalist’s mind to predict where foods will be. Tracking in particular requires many sophisticated cognitive skills, including both deductive and inductive thinking.68 To be sure, the first hunter-gatherers 2 million years ago were not as cognitively advanced as people today, but they must have benefited from having bigger, better brains than "
― Daniel E. Lieberman , The Story of the Human Body: Evolution, Health, and Disease
126
" Beyond physical activity and estrogen, the other major factor that increases the risk of osteoporosis is diet, especially calcium. A body needs abundant calcium to function properly, and one of bone’s many jobs is to serve as a reservoir of this vital mineral. If calcium levels in the blood drop too much because of insufficient calcium from food, hormones stimulate osteoclasts to resorb bone, restoring calcium balance. This response, however, weakens bones if the tissue is not replaced. Consequently, both animals and people whose diets are permanently deficient in calcium develop flimsy bones, and they lose bone more rapidly as they age. Modern grain-based diets, moreover, tend to be woefully deficient in calcium—between two and five times lower than typical hunter-gatherer diets, and only a minority of adult Americans eat sufficient calcium.16 This problem, moreover, is often exacerbated by low levels of vitamin D, which helps the gut absorb calcium, and by low levels of dietary protein, which is also necessary to synthesize bone. "
― Daniel E. Lieberman , The Story of the Human Body: Evolution, Health, and Disease
129
" Your body is host to a microbiome: the trillions of other organisms that naturally inhabit your gut, respiratory tract, skin, and other organs. According to some estimates, there are ten times as many foreign microbes in your body as there are of your own cells, and altogether these microbes weigh several pounds.27 We coevolved with these microbes as well as with many species of worms over millions of years, which explains why most of your microbiome is either harmless or performs important functions, such as helping you digest and cleaning your skin and scalp.28 You depend on these critters as much as they depend on you, and were you to eradicate them, you would suffer. Fortunately, antibiotics and antiparasitic drugs don’t kill off your entire microbiome, but the overuse of these powerful medications does eliminate some helpful microbes and worms, whose absence may actually contribute to new diseases. "
― Daniel E. Lieberman , The Story of the Human Body: Evolution, Health, and Disease
132
" An even more important invention was the control of fire. No one is quite sure when humans first managed to regularly create and use fire. Currently, the earliest evidence for the controlled use of fire by humans comes from a million-year-old site in South Africa and from a 790,000-year-old site in Israel.18 Traces of fire, however, remain rare until 400,000 years ago, when fireplaces and burnt bones start showing up regularly in sites, suggesting that archaic Homo, unlike H. erectus, habitually cooked its food.19 Cooking, when it did catch on, was a transformative advance. For one, cooked food yields much more energy than uncooked food and is less likely to make you sick. Fire also allowed archaic humans to keep warm in cold habitats, to fend off dangerous predators, like cave bears, and to stay up late at night. "
― Daniel E. Lieberman , The Story of the Human Body: Evolution, Health, and Disease
134
" In short, there is good reason to believe that asthma and other allergies are mismatch diseases in which too little exposure to microorganisms contribute to an imbalance that, paradoxically, causes too much of a response to otherwise harmless foreign substances. The immune system, however, is far more complex than the above description, and there is no question that other factors—many of them genetic—also play key roles. Twins, for example, are more likely than not to share the same allergy. "
― Daniel E. Lieberman , The Story of the Human Body: Evolution, Health, and Disease
136
" humans have been walking and running on their bare feet for millions of years, and many people still do. Moreover, when people did start to wear shoes, probably around 45,000 years ago,2 their footwear was minimal by today’s standards, without thick, cushioned heels, arch supports, and other common features. The oldest known sandals, dated to 10,000 years ago, had thin soles that were tied onto the ankle with twine; the oldest preserved shoes, dated to 5,500 years ago, were basically moccasins.3 Shoes are now ubiquitous in the developed world, where being barefoot is often considered eccentric, vulgar, or unhygienic. Many restaurants and businesses won’t serve barefoot customers, and it is commonly believed that comfortable, supportive shoes are healthy.4 The mind-set that wearing shoes is more normal and better than being barefoot has been especially evident in the controversy over barefoot running. Interest in the topic was ignited in 2009 by the best-selling book Born to Run, which was about an ultramarathon in a remote region of northern Mexico, but which also argued that running shoes cause injury.5 A year later, my colleagues and I published a study on how and why barefoot people can run comfortably on hard surfaces by landing in an impact-free way that requires no cushioning from a shoe (more on this below).6 Ever since, there has been much passionate public debate. And, as is often the case, the most extreme views tend to get the most attention. At one extreme are enthusiasts of barefoot running, who decry shoes as unnecessary and injurious, and at the other extreme are vigorous opponents of barefoot running, who think that most runners should wear supportive shoes to avoid injury. Some "
― Daniel E. Lieberman , The Story of the Human Body: Evolution, Health, and Disease
138
" The end product of all that evolution is that we are big-brained, moderately fat bipeds who reproduce relatively rapidly but take a long time to mature. We are also adapted to be physically active endurance athletes who regularly walk and run long distances and who frequently climb, dig, and carry things. We evolved to eat a diverse diet that includes fruits, tubers, wild game, seeds, nuts, and other foods that tend to be low in sugar, simple carbohydrates, and salt but high in protein, complex carbohydrates, fiber, and vitamins. Humans are also marvelously adapted to make and use tools, to communicate effectively, to cooperate intensively, to innovate, and to use culture to cope with a wide range of challenges. These extraordinary cultural capacities enabled Homo sapiens to spread rapidly across the planet and then, paradoxically, cease being hunter-gatherers. "
― Daniel E. Lieberman , The Story of the Human Body: Evolution, Health, and Disease
140
" Almost every major infectious epidemic, such as smallpox, polio, and the plague, happened after the Agricultural Revolution began. In addition, studies of recent hunter-gatherers show that although they don’t enjoy surpluses of food, they rarely suffer from famines or serious malnutrition. Modern lifestyles have also fostered new noncommunicable but widespread illnesses such as heart disease, certain cancers, osteoporosis, type 2 diabetes, and Alzheimer’s, as well as scores of other lesser ailments, such as cavities and chronic constipation. There is good reason to believe that modern environments contribute to a sizeable percentage of mental illnesses, such as anxiety and depressive disorders.2 The "
― Daniel E. Lieberman , The Story of the Human Body: Evolution, Health, and Disease
