The Story of the Human Body Quotes

“We didn’t evolve to be healthy, but instead we were selected to have as many offspring as possible under diverse, challenging conditions. As a consequence, we never evolved to make rational choices about what to eat or how to exercise in conditions of abundance and comfort.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“The fundamental answer to why so many humans are now getting sick from previously rare illnesses is that many of the body's features were adapted in environments from which we evolved, but have become maladapted in the modern environments we have now created. This idea, known as the mismatch hypothesis, is the core of the new emerging field of evolutionary medicine, which applies evolutionary biology to health and disease.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“general trend is that people who frequently carry heavy loads and do other “back-breaking” work get fewer back injuries than those who sit in chairs for hours bent over a machine.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“Our body’s evolutionary journey is also far from over. Natural selection didn’t stop when farming started but instead has continued and continues to adapt populations to changing diets, germs, and environments. Yet the rate and power of cultural evolution has vastly outpaced the rate and power of natural selection, and the bodies we inherited are still adapted to a significant extent to the various and diverse environmental conditions in which we evolved over millions of years. 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.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“There is nearly universal consensus that we should prohibit selling and serving alcohol to minors because wine, beer, and spirits can be addictive and, when used to excess, ruinous for their health. Is excess sugar any different?”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“Muscle imbalances caused by hours of sitting in chairs have also been hypothesized to contribute to one of the most common health problems on the planet: lower back pain. Depending on where you live and what you do, your chances of getting lower back pain are between 60 and 90 percent.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“We have much to learn about myopia, but two facts are clear. First, myopia is a formerly rare evolutionary mismatch that is exacerbated by modern environments. Second, even though we don’t entirely understand which factors cause children’s eyeballs to elongate too much, we do know how to treat the symptoms of myopia effectively with eyeglasses. Eyeglasses”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“When Franklin D. Roosevelt signed the Social Security Act in 1935, old age was defined as sixty-five years, yet estimated life expectancy in the United States at the time was sixty-one years for males and sixty-four years for females.62 A senior citizen today, however, can expect to live eighteen to twenty years longer. The downside is that he or she also should expect to die more slowly. The two most common causes of death in 1935 America were respiratory diseases (pneumonia and influenza) and infectious diarrhea, both of which kill rapidly. In contrast, the two most common causes of death in 2007 America were heart disease and cancer (each accounted for about 25 percent of total deaths). Some heart attack victims die within minutes or hours, but most elderly people with heart disease survive for years while coping with complications such as high blood pressure, congestive heart failure, general weakness, and peripheral vascular disease. Many cancer patients also remain alive for several years following their diagnosis because of chemo-therapy, radiation, surgery, and other treatments. In addition, many of the other leading causes of death today are chronic illnesses such as asthma, Alzheimer’s, type 2 diabetes, and kidney disease, and there has been an upsurge in the occurrence of nonfatal but chronic illnesses such as osteoarthritis, gout, dementia, and hearing loss.63 Altogether, the growing prevalence of chronic illness among middle-aged and elderly individuals is contributing to a health-care crisis because the children born during the post–World War II baby boom are now entering old age, and an unprecedented percentage of them are suffering from lingering, disabling, and costly diseases. The term epidemiologists coined for this phenomenon is the “extension of morbidity.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“In short, the invention of agriculture caused the human food supply to increase in quantity and deteriorate in quality, but food industrialization multiplied this effect. Over”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“An evolutionary perspective predicts that most diets and fitness programs will fail, as they do, because we still don’t know how to counter once-adaptive primal instincts to eat donuts and take the elevator.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“Farming is often viewed as an old-fashioned way of life, but from an evolutionary perspective, it is a recent, unique, and comparatively bizarre way to live.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“Another relevant factor is money. In the United States and many other countries, health care is partly a for-profit industry.21 Consequently, there is a strong incentive to invest in or promote treatments such as antacids and orthotics that alleviate the symptoms of diseases and that people have to buy frequently and for many years. Another way to make lots of money is to favor costly procedures like surgery instead of less expensive preventive treatments like physical therapy. Preventive”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“no matter how you look at the issue, prevention is a fundamentally preferable and more cost-effective way to promote health and longevity. Most people agree that we invest insufficiently in prevention, but they would also surmise that it is difficult to get young, healthy people to avoid behaviors that increase their risk of future illness. Consider smoking, which causes more preventable deaths than any major risk factor (the other big ones being physical inactivity, poor diet, and alcohol abuse). After prolonged legal battles, public health efforts to discourage smoking have managed to halve the percentage of Americans who smoke since the 1950s.19 Yet 20 percent of Americans still smoke, causing 443,000 premature deaths in 2011 at a direct cost of $96 billion per year. Likewise, most Americans know they should be physically active and eat a healthy diet, yet only 20 percent of Americans meet the government’s recommendations for physical activity, and fewer than 20 percent meet government dietary guidelines.20 There are many, diverse reasons we are bad at persuading, nudging, or otherwise encouraging people to use their bodies more as they evolved to be used (more on this later), but one contributing factor could be that we are still following in the footsteps of the marquis de Condorcet, waiting for the next promised breakthrough. Scared of death and hopeful about science, we spend billions of dollars trying to figure out how to regrow diseased organs, hunting for new drugs, and designing artifical body parts to replace the ones we wear out. I am in no way suggesting that we cease investing in these and other areas. Quite the contrary: let’s spend more! But let’s not do so in a way that promotes the pernicious feedback loop of just treating mismatch diseases rather than preventing them. In practical”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“Fructose, which is often paired with glucose, is naturally present in fruit and honey, as well as table sugar (sucrose, which is 50 percent fructose). Assuming your baker used plenty of sugar, your cake probably has a fair amount of fructose. Unlike glucose, which can be metabolized (essentially burned) by cells throughout the body, fructose is almost entirely metabolized by the liver. The liver, however, can burn only so much fructose at once, so it converts any excess fructose into fat, which again is either stored in the liver or dumped into the bloodstream. As we will see, both of these fates cause problems.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“The final and most important point about adaptation is really a
crucial caveat: no organism is primarily adapted to be healthy, long-
lived, happy, or to achieve many other goals for which people strive.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“study of thirty thousand elderly people in fifty-two countries found that switching to an overall healthy lifestyle—eating a diet rich in fruits and vegetables, not smoking, exercising moderately, and not drinking too much alcohol—lowered heart disease rates by approximately 50 percent.14 Reducing exposure to carcinogens, such as tobacco and sodium nitrite, have been shown to decrease the incidence of lung and stomach cancers, and it is likely (more evidence is needed) that lowering exposures to other known carcinogens, such as benzene and formaldehyde, will reduce the incidence of other cancers. Prevention really is the most powerful medicine, but we as a species consistently lack the political or psychological will to act preventively in our own best interests. It is worthwhile to ask to what extent efforts to treat the symptoms of common mismatch diseases have the effect of promoting dysevolution by taking attention and resources away from prevention. On an individual level, am I more likely to eat unhealthy foods and exercise insufficiently if I know I’ll have access to medical care to treat the symptoms of the diseases these choices cause many years later? More broadly within our society, is the money we allocate to treating diseases coming at the expense of money to prevent them?”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“These visceral (belly) fat cells behave differently than fat elsewhere in the body in two important ways.25 First, they are several times more sensitive to hormones and thus tend to be more metabolically active, which means they are capable of storing and releasing fat more rapidly than fat cells in other parts of the body. Second, when visceral cells release fatty acids (something fat cells do all the time), they dump the molecules almost straight into the liver, where the fat accumulates and eventually impairs the liver’s ability to regulate the release of glucose into the blood. An excess of belly fat (a paunch) is therefore a much greater risk factor for metabolic disease than a high BMI.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“typical adult American male in 1900 had a healthy BMI of about 23, but since then BMI has steadily increased, albeit with a slight dip after World War II. The”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“More food is good, but agricultural diets can provoke mismatch diseases. One of the biggest problems is a loss of nutritional variety and quality. Hunter-gatherers survive because they eat just about anything and everything that is edible. Hunter-gatherers therefore necessarily consume an extremely diverse diet, typically including many dozens of plant species in any given season.26 In contrast, farmers sacrifice quality and diversity for quantity by focusing their efforts on just a few staple crops with high yields. It is likely that more than 50 percent of the calories you consume today derived from rice, corn, wheat, or potatoes. Other crops that have sometimes served as staples for farmers include grains like millet, barley, and rye and starchy roots such as taro and cassava. Staple crops can be grown easily in massive quantities, they are rich in calories, and they can be stored for long periods of time after harvest. One of their chief drawbacks, however, is that they tend to be much less rich in vitamins and minerals than most of the wild plants consumed by hunter-gatherers and other primates.27 Farmers who rely too much on staple crops without supplemental foods such as meat, fruits, and other vegetables (especially legumes) risk nutritional deficiencies. Unlike hunter-gatherers, farmers are susceptible to diseases such as scurvy (from insufficient vitamin C), pellagra (from insufficient vitamin B3), beriberi (from insufficient vitamin B1), goiter (from insufficient iodine), and anemia (from insufficient iron).28 Relying heavily on a few crops—sometimes just one crop—has other serious disadvantages, the biggest being the potential for periodic food shortages and famine. Humans,”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“Humans can sweat more than a liter per hour, enough to cool an athlete running hard in hot conditions. Even though the temperature at the 2004 Olympic women’s marathon in Athens reached 35 degrees Celsius (95 degrees Fahrenheit), high sweat rates enabled the winner to run at an average speed of 17.3 kilometers (10.7 miles) per hour for more than two hours without overheating! No other mammal can do that because they lack sweat glands, and because most mammals are covered with fur. Fur”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“We are still evolving. Right now, however, the most potent form of evolution is not biological evolution of the sort described by Darwin, but cultural evolution, in which we develop and pass on new ideas and behaviors to our children, friends, and others. Some of these novel behaviors, especially the foods we eat and the activities we do (or don’t do), make us sick.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“Like sex, evolution elicits equally strong opinions from those who study it professionally and those who consider it so wrong and dangerous that they believe the subject shouldn’t be taught to children. Yet,”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease

“Your guts also have about 100 million nerves, more than the number of nerves in your spinal cord or your entire peripheral nervous system.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“According to one calculation, everyone alive today descends from a population of fewer than 14,000 breeding individuals from sub-Saharan Africa, and the initial population that gave rise to all non-Africans was probably fewer than 3,000 people.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“Dobzhansky, T. (1973). Nothing in biology makes sense except in the light of evolution. The American Biology Teacher 35: 125–29.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“Our recent divergence from a small population explains another important fact, one that every human ought to know: we are a genetically homogenous species.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“Food processors, dishwashers, vacuum cleaners, and clothes-washing machines have substancially lessened the physical activity required to cook and clean. Air conditioners and central heating have decreased how much energy our bodies spend to maintain a stable body temperature. Countless other devices, such as electric can openers, remote controls, electric razors and suitcases on wheels, have reduced, calorie by calorie, the amount of energy we expend to exist.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“Man's best friend, the dog, was actually the first domesticated species. We bred dogs from wolves more than 12,000 years ago, but there is much debate over when, and how this domestication ocurred (and to what extent dogs actually domesticated us).”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“Like it or not, we are slightly fat, furless, bipedal primates who crave sugar, salt, fat, and starch, but we are still adapted to eating a diverse diet of fibrous fruits and vegetables, nuts, seeds, tubers, and lean meat. We enjoy rest and relaxation, but our bodies are still those of endurance athletes evolved to walk many miles a day and often run, as well as dig, climb, and carry. We love many comforts, but we are not well adapted to spend our days indoors in chairs, wearing supportive shoes, staring at books or screens for hours on end. As a result, billions of people suffer from diseases of affluence, novelty, and disuse that used to be rare or unknown. We then treat the symptoms of these diseases because it is easier, more profitable, and more urgent than treating their causes, many of which we don’t understand anyway. In doing so, we perpetuate a pernicious feedback loop—dysevolution—between culture and biology. Maybe”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease

“These natural tendencies then make us vulnerable to manufacturers and marketers who easily exploit our basic urges to eat too much, eat the wrong foods, and exercise too little. Because these unhealthy behaviors are deep instincts they are very difficult to overcome. The bottom line is that knowledge is power, but not enough. Most of us need information and skills, but we also require motivation and reinforcement to overcome basic urges in order to make healthier choices in environments replete with plentiful food and labor-saving devices.”
― Daniel E. Lieberman, The Story of the Human Body: Evolution, Health and Disease