The United States is in the midst of a health crisis! Eighty percent of American women and 60 percent of the men are trying to lose weight or not gain more weight, and they are spending over 30 billion dollars a year in the process. Fewer and fewer of us are considered physically fit, at any age.

According to data collected by the CDC (Centers for Disease Control and Prevention) nearly 65% of all Americans are now overweight, a percentage that is rising each year. In that same group the number of people who are now considered obese (more than 20% over a person's ideal body weight) has nearly doubled since 1980 to an estimated 30% of the U.S. population. Even more alarming are the latest data showing that 13% of all children in the U.S. are now seriously overweight.

As Mark Sorensen of Northwestern University has noted, a European Neanderthal living in near arctic conditions would have needed about 4,000 kilocalories (more commonly called calories) a day to sustain himself. This compares with the modern needs of a typical, urban American male of only 2,600 calories. The problem today is that many of us are still eating as if we were Neanderthals.

How did this happen? Jeffrey Koplan, director of the CDC, notes that during the past two decades the daily consumption of calories for women in America has increased by 7% and for men by 10%. This, he says is the result of changes in our habits that now include a greater variety of fatty foods, foods with more calories, the expansion and availability of fast foods, the successful marketing of new high-calorie snack foods, and a tendency to use food and drink as the centerpiece while socializing. Also alarming is that less than 30% of Americans say they follow the CDC's recommendation to exercise at least 30 minutes three times a week

Is there hope? Yes, but we need to look to earlier times for our answers. As an anthropologist, I have spent more than 35 years sifting through the remains of our prehistoric ancestors searching for information about how long they lived, how healthy they were, and what they ate. What I am finding indicates that most of them ate better diets and enjoyed better health than we do.

Humans evolved more than four million years ago, and for most of that time we have lived as nomadic hunters and gatherers. It has only been during the last 10,000 years that some groups abandoned foraging to pursue agriculture and animal herding. Throughout those early millions of years during the pre-agricultural era, life was physically demanding, but healthy. Many died early, but their diet was not at fault. Accidents, infection, and a body worn out from a physically stressful lifestyle each took their toll.

The archaeological evidence gleaned from skeletons, trash pits, the remains of meals found in preserved human feces (coprolites), and artifacts tell us quite a bit about the lifestyles of our ancestors and questions the so-called dietary advances created by our lifestyle as farmers and herders.

Nutritionists and doctors tell us that our prehistoric ancestors ate "the perfect human diet and lived the perfect lifestyle", and that we need to return to many of those essential principles. Today the human body and digestive system is essentially the same as it was millions of years ago; yet for most of the people living in the world's most affluent nations lifestyles and diets have changed radically.

The problem is our technology that has advanced far beyond the wildest dreams of our prehistoric ancestors. Yet, for all of our great advancements we are still locked into a body style that is millions of years old. Our body, and our digestive system were honed to perfection during that 99% of human existence when everyone was a nomadic hunter and gatherer. Then, 10,000 years ago in the Middle East our ancestors first domesticated plants and animals and settled down. Soon, this new lifestyle spread to other world areas such as west Africa, southeast Asia, and to Central and South America. How these events affected and altered human cultures are phenomenal, yet human genetics and biology have changed very little.

Many claim that farming should be listed as the single greatest invention in all of human existence. Others, like physiologist and Pulitzer Prize winner Jared Diamond of UCLA, believe, "the adoption of agriculture, supposedly our most decisive step towards a better life, was in many ways a catastrophe from which we have never recovered".

How can his statement be true? Aren't we taught that the growing of crops and raising of animals frees us from the perils of an uncertain food supply and provides us with ample leisure time to develop art, music, and science? For most of the affluent societies of the world, haven't the fruits of the agricultural revolution been a longer life span, electricity, central cooling and heating, automobiles, airplanes, television, computers, and a life of pampered comfort? For most of the world's wealthy people, doesn't the only strenuous physical exertion come from short periods of self-imposed exercise each week?

Should we trade our twenty-first century lifestyle for theirs just because we are told our pre-agricultural ancestors lived the "perfect lifestyle" and ate the "the perfect diet?" I think not. But, it is possible to change aspects of our current lifestyle and diets to mirror the lessons we are learning from the lives of our ancient ancestors. Shouldn't we try to improve our health and daily lives without sacrificing the technological achievements we now cherish?

Ancient Hunters and Gatherers

Humans inherited a body that was originally designed for our tree-dwelling primate ancestors. Fortunately, some of those physical traits became advantages. Large brains, grasping hands, stereoscopic and color vision, and social lifestyles are just some of these. Humans also have the advantage of not being physically specialized, meaning that we can adapt to life in many different environments. It's true that some minor physiological changes have occurred in humans since we first developed. Some groups living at high altitudes have developed larger lung capacities while others living in hot desert regions have dark, protecting skin color and tend to be tall and thin because it maximizes the body's ability to dissipate heat. Nevertheless, in cold climates we use warm clothes in place of body hair, to travel by sea we use boats in place of gills and flippers, and to travel long distances we use airplanes instead of wings.

Our biped walking on two feet instead of four made traveling long distances easier and less costly in terms of calories burned as energy. Our hairless bodies and ability to sweat allowed our ancestors to move around in safety during the heat of the day when most other large animals, and especially predators, had to rest in the shade or risk overheating and dying of sunstroke. Our ability to consume and digest both plant and animal foods is another advantage because it enables us to use many different resources and eat almost anything. More importantly, it helped our ancestors find enough food to feed the needs of our large brains.

The brain is a greedy organ that consumes a tremendous amount of energy. By weight, brain tissue uses about 16 times more energy per minute than does muscle tissue. Even when resting or sleeping, the human brain still consumes about 25% of the total energy being used by a human. During similar resting stages the smaller brains of most non-primate mammals use only 3-5% of the total body's energy. These data have lead anthropologists such as William Leonard of Northwestern University to suggest that human brains probably grew larger only after our earliest ancestors became skilled at finding sufficient amounts of high-calorie foods (protein and fats) to feed the voracious needs of their expanding brains. Even though an improved diet played a critical role, he notes that it was not the only factor that probably led to an increased brain size in humans.

The archaeological evidence left by our ancient ancestors attests to their skills as hunters and gives us important clues about their lifestyles, diets, and nutrition. In addition, when comparing the skeletons from ancient hunting and gathering societies to the skeletons of early farming cultures we find chilling evidence of what happened to the lives and health of most of the world's early agricultural, and later urban populations.

According to anthropologist George Armelagos of Emory University, high levels of bone porosity in the vault of the skull and around the eye orbits, called porotic hyperostosis, are considered good indicators of long-term anemia, commonly attributed to iron deficiency. Although porosity might be caused by other conditions, such as severe hookworm infections, the most frequent link is to long-term reliance on diets that are low in meat and high in carbohydrates; a common occurrence in early farming cultures where diets consisted mostly of cereal grains.

When Dr. Armelagos compared human skeletons from pre-agricultural foraging peoples who lived in the Illinois and Ohio River valleys with those of later farming cultures in the same region, the evidence of anemia in the farming group was overwhelming. He found a 400% increase in the occurrence of porotic hyperostosis among skeletons from the farming period, whose diets consisted mostly of maize.

Professor Jane Buikstra, of the University of Chicago's anthropology department, notes that humans who experience episodes of severe physical stress often carry a record of those events in the long bones of their arms and legs and in the enamel layers of their teeth. She identifies typical types of stress as periods of prolonged or serious famine, periods of severe infection, or stress caused by malnutrition.

One type of growth-related stress indicator is known as Harris lines, which can be seen during x-ray or cross-section examinations of human long bones. Although most common in the skeletons of farming cultures, Harris lines occasionally appear in the skeletons of some foragers. Many now believe that some types of Harris lines reflect relatively short periods of stress while other lines indicate prolonged periods of stress.

Dr. Buikstra has noted that studies of North American skeletons from foraging groups and from early farming cultures show noticeable differences. The long bones from the farming groups have thinner cortical thickness, and are shorter, indicating a reduction in body height after the switch to farming. These, she believes, represent the physical effects of chronic malnutrition after the switch to farming.

Another reliable indicator of diet and nutritional-related stress is abnormal development in the enamel layer of teeth. One type of tooth abnormality is called linear enamel hypoplasia and seems to be caused by severe physical stress. This condition, which appears as depressed and pitted areas in the enamel layer of teeth, is more commonly seen in the teeth of early farming cultures than in those of foragers.

Wilson bands, another type of tooth enamel abnormality, are also linked to stress-induced growth disruptions and are much more prevalent in the skeletons from farming cultures than foraging ones. When the teeth from burials belonging to farming cultures are examined, they show large numbers of enamel abnormalities and large numbers of dental caries. By contrast, rarely is either of these conditions found in the teeth of earlier foraging groups.

Susceptibility to dental caries varies with individuals, but in all cases the potential for infection is greater on diets containing large amounts of refined carbohydrates, especially sugars. About 2% of the fossil teeth from ancient foraging cultures contain small or shallow areas of decay of the pit and fissure types and these are found mostly on the occlusal (top) surface of teeth. However, after cultures turned to farming the record of dental decay increased dramatically. Even so, it wasn't until the widespread use of factory-produced refined carbohydrates, including sugar, that human dental decay reached its current epidemic proportions. One study, conducted in 1900 of factory workers in England, revealed that 70% of their teeth contained caries. More importantly, most of the dental decay occurred in between their teeth, which are locations associated almost exclusively with post-agricultural diets composed of finely-ground cereals and sugars.

Examinations of preserved human coprolites provide another valuable source of information about our prehistoric ancestors. Coprolites are ideal records because they contain the nondigestible remains of human diets, such as fiber, insect parts, bones, hair, feathers, shells, seeds, pollen, and the leaves of foods that were actually eaten. In recent years, the scientific study of coprolites has provided valuable clues about the diets, health, and nutrition of ancient foraging peoples as well as those living in early agricultural communities.

Anthropologist Kristen Sobolik of the University of Maine has spent most of her career examining human coprolites found in prehistoric sites of the arid American Southwest. She has found that for thousands of years ancient foragers ate diets composed mostly of nutritious plant foods that are high in fiber such as sunflower seeds, ground mesquite pods, cactus seeds, acorns, walnuts, pecans, persimmons, grapes, dewberries, the soft basal leaf portion of desert plants such as sotol and agave, and cactus flowers, fruits, and pads. These ancient foragers balanced their mostly plant-food diets with about 15-30% meat protein and minimal amounts of fat obtained from tiny, lean animals such as mice, rabbits, birds, fish ranging from minnows to small catfish and gar, freshwater clams, small rock lizards, caterpillars, grasshoppers, bird eggs, and, when they were lucky, maybe a deer.

Karl Reinhard, an anthropologist at the University of Nebraska, is a leading authority on ancient human parasite infection. He notes that intestinal parasites can be debilitating and potentially fatal, especially when they infect a person who is already weakened by episodes of famine or prolonged malnutrition. His examination of human coprolites recovered from many regions of North and South America indicates that hunting and gathering populations were almost totally free of intestinal parasitic infections. However, once groups settled down and turned to farming, they became heavily infected. High population densities, poor sanitation, and the compactness of living spaces in small farming villages and pueblos skyrocketed the infection rates of nearly a dozen types of intestinal parasites including pin worms, tapeworms, and thorny-headed worms.

The Human Body

Carbohydrates: Humans rely on three primary food sources to provide them with energy and needed building materials—carbohydrates, protein, and fats. The continual need to replenish these components is what gives us the desire to eat. In addition, our bodies also require certain other substances such as sodium, potassium, calcium, and a variety of other important minerals and vitamins.

Plants provide our primary source of carbohydrates and most of the calories we use as energy. Each gram of carbohydrate (about 1/28th of an ounce) provides four kilocalories of energy when it is completely digested. There are two main types of carbohydrates, simple and complex. The simple carbohydrates are sugars. They exist naturally as monosaccharides - different types of single-molecule sugars (glucose, dextrose, fructose, galactose), or as disaccharides - double-molecule sugars (sucrose, maltose, lactose). Our bodies digest both types and both are found naturally in fruits, flower nectar, and the sap of some plants. The complex carbohydrates come mostly from starch and cellulose.

Our taste buds love sweet things. Perhaps this is because our primate ancestors learned that sweet fruits are rarely poisonous and are good sources of food. Tree fruits were a much sought-after food source by primates because ounce for ounce fruits offer more usable calories than do leaves, bark, or stems. In addition, the riper the fruit, the sweeter it becomes as its starch is converted to sugars.

The association of sweetness with "good tasting", ready-to-eat, high-calorie-value fruits served the early primates and our human ancestors well. It encouraged them to search for these tasty food sources and to avoid most sour and bitter-tasting fruits because that often indicates fruits are poisonous or not yet ripe. Our ancient ancestors never ate too much sugar. Except for small amounts of sugar found in fruits, in a few other natural foods, and an occasional lucky discovery of honey, our foraging ancestors, and even early farming peoples, had no access to sugar. No human forager, or early farmer, was ever in danger of overdosing on sugar. Perhaps this is why of the four essential taste sensations (sour, sweet, salty, bitter), humans usually avoid foods that are too sour, too salty, or too bitter, but rarely turn away from foods that are too sweet.

Two events increased our consumption of sugar. First, Columbus carried sugarcane to the New World and found that it grew well in the moist climate and fertile soils of the Caribbean. Second, the Spanish and Portuguese pioneered the importing of slaves as an inexpensive labor source for their plantations that soon produced tons of sugar at competitive market prices. For example, in England, the availability of inexpensive sugar from the New World reduced the per pound cost from the equivalent price equal to the yearly salary of an average worker in 1600, to the same price as a dozen eggs by 1700. As the price of sugar dropped, consumption rose so that soon the United States and most European countries mirrored the English's rapid increase in the use of sugar.

By 1913 the annual consumption of sugar in the U.S. had reached 75 pounds per person. By 1976, U.S. sugar consumption had reached 125 pounds per person per year, which represents about 11% of the total daily calories eaten by each American. By 1998, sugar was supplying 16% of the total daily calories for each U.S. adult and 20% of children's daily calories.

Anthropologist Sidney Mintz of John Hopkins University believes he knows why the U.S.and world sugar consumption continues to climb. He notes that only a small portion of each person's daily sugar consumption comes from spoonfuls or cubes of sugar those individuals add to foods or drink. Instead, most of the sugar we eat is "hidden". Bakers add sugar to non yeast-rising products because it makes cakes, cookies, and breads smoother, softer and whiter. Sugars also improve the texture of baked goods. Manufacturers produce heavily sugared soft drinks because thicker syrup-like liquids are smoother and more appealing to the mouth and tongue than is flavored water. Sugar also slows staleness in bread, stabilizes the chemical contents of salt, cloaks the acidity of tomatoes in catsup, and when added as a sauce to bland-tasting meats like fish and poultry, sugar makes them taste much "better".

The complex carbohydrates have long chains of linked sugar molecules called polysaccharides. Humans can't digest some types, such as cellulose, so it becomes the "fiber" content of our diets. Other types of carbohydrates, such as starch, are digestible and can be converted to energy.

Paradoxically, until very recently, too much diet fiber was a problem in most human diets. Our ancient ancestors pounded and ground plant foods, techniques that exposed starches but did not reduce the intake of high amounts of fiber. Dr. Boyd Eaton and his colleagues at the Emory University School of Medicine estimate that our foraging ancestors probably consumed about 150 g of fiber each day as compared to the current USDA recommended minimal average of 20-25 g of fiber daily. Even so, the average American usually eats less than 10 g of fiber each day.

My coprolite studies of pre-agricultural groups living in North and South America support Dr. Eaton's estimates of high fiber in ancient diets. In many instances, I find that non-digested fiber is the dominant component of ancient coprolites from pre-agricultural foragers. In some cases I find that fiber accounts for more than one half of the total weight of each coprolite.

Our digestive system still needs lots of fiber. Fiber speeds the passage of food through our small intestines, adds needed bulk for our large intestine, stimulates peristalsis necessary for the excretion process, and minimizes the effects of ingested carcinogens, which might otherwise cause some of the DNA in our digestive tract to mutate into cancers. Low fiber diets are also a factor in the occurrence of disorders such as spastic colon, diverticulosis, hiatal hernia, and hemorrhoids.

Animal Protein: All primates eat some type of animal protein but humans eat the highest amounts. Protein is a high-calorie food that our ancient ancestors needed to feed the high-energy needs of our large brain. When eaten, 3.5 ounces of meat produces about 200 calories of energy while the same amount of fruit yields less than 100 calories and 3.5 ounces of leaves produces only 10-20 calories.

Anthropologist Richard Lee of the University of Toronto has spent a lifetime studying the diets of contemporary foraging societies. He estimates that most of today's foraging societies obtain about one-third of their daily calories from animal protein, with the other two-thirds coming from plant foods. That amount is considerably higher than the average diet of 5-7% animal protein eaten by our closest relatives, the chimpanzees. William Leonard and others note that larger-brained humans need more high-calorie foods than do the smaller-brained chimps. Lee also notes that among contemporary foragers a significant percentage of their meat often comes from small reptiles, birds, and mammals. My examination of ancient human coprolites confirms that reliance on meat protein mainly from small animal hunting seems to be thousands of years old and may represent an essential pattern even from the beginning of humankind.

Humans need a constant supply of protein because unlike fats and carbohydrates, our body cannot store protein as protein. Instead, humans store excess protein as fat. Meat from animals, fish, and fowl contains from 15-40% protein by weight and is called "a complete protein source." By contrast, most plant foods often contain meager amounts of about 2-10% protein and are termed "incomplete proteins" because plant sources often lack at least one or more essential amino acids needed by all humans.

The increased need for protein to feed our larger brains may explain why Homo erectus, the first of our species with a brain nearly as large as modern humans, left the grasslands of east Africa and soon ranged over much of Europe, Asia, and the rest of Africa. Anthropologist Susan Anton of Rutgers University and others estimate that by the time Homo erectus emerged somewhere between 1-2 million years ago, the human needs for food and especially protein meant that this new species needed eight to ten times more room to search for food than did their smaller-brained ancestors who were restricted to the continent of Africa.

How much protein do humans really need? Nutritionists say about 10-20% of our diets should come from meat protein, a percentage that is within the minimal average eaten by most non-poverty-level Americans. For many of our ancient foraging societies about one-third of their daily calories came from animal sources and most of that came from meat. Nevertheless, archaeological records also indicate that some of our ancient ancestors, especially the ones we call the "big game hunters", probably relied on meat sources for as much as 50-60% of their total dietary calories.

Humans need protein because it provides the essential amino acids used by our bodies to build new tissues such as muscles, tendons, ligaments, and the walls of blood vessels. All of our growth from birth to death, as well as all repairs to our body, depends upon the amino acids we obtain from protein sources. Even our skin, hair, and nails cannot form properly without the correct amount and mixture of amino acids.

Fats: Until very recently human diets were low in fat. Fats are found in some plant foods, such as seeds and nuts, and in the meat of animals. In prehistoric times fat was a hard-to-find food source because most wild, land-dwelling animals have lean bodies with less than 4% fat. By contrast, 30% or more of the total butchered carcass weight of most American domestic cattle and pigs is fat.

Most fats are composed of long chains of triglycerides molecules. They get their name because each contains three fatty acids attached to one glycerol molecule. Cholesterol, sometimes mistakenly called a fat, is needed to produce numerous hormones and bile acids, but it is not really a fat. Instead, cholesterol is a complicated substance composed of molecule rings that reacts more like a wax than a true fat.

There are many types of fatty acids found in nature. Some fats are saturated, others are unsaturated fats, and the unsaturated group is divided into mono or poly types depending on whether they are linked with one, or more, double bonds of carbon. The chemistry of fatty acids is complex, so for most of us knowing how they work in the human body is more important. When digested, fats also offer the most energy calories (9) per gram.

Some polyunsaturated fats are called structural fats because they are used to build and repair nearly all cell membranes. These fats are also important because they are used to build various types of hormones and utilize various vitamins that regulate our body functions. By contrast, most saturated fats occur as adipose tissue, which is where animals store excess amounts of fat for later use. In some animals, such as seals, whales, or bears, a thick layer of subcutaneous adipose fat is essential because it provides insulation against the cold or it becomes stored calories for use during hibernation. However, in most animals excess amounts of saturated fats are stored in other body locations, such as in the abdominal cavity or within muscle tissue where it can be converted into energy when needed.

The meat of wild animals provides much more protein than fat. Wild animals have small amounts of saturated fat that is often distributed uniformly throughout the body, yet most fat in wild animals is the unsaturated type. Animals raised in captivity, our pets, and steers raised in feed lots as food have one thing in common--- they all have high amounts of saturated fat.

I often ask students in my classes to list their ten favorite foods. With rare exception, all foods listed contain fats. Of the foods humans like most, the majority contains fats. It is unfortunate for humans that fats will satisfy our hunger pangs quicker than any other food source. Million's of years ago it was nature's way of encouraging our ancestors to find and eat this essential food item. This food craving served our foraging ancestors well, but it has become a liability for many of us today. What is worse is that nature designed our intestines to be very efficient at digesting fats, generally allowing no more than 5% to escape before being absorbed. This digestive advantage provided an essential advantage for our ancient ancestors who rarely ate fat, but it is one of the factors that now contribute to making more than 65% of Americans overweight.

It is the amount of saturated fat and trans fat in our diet that should be cause for alarm. The U.S. Senate's Select Committee on Nutrition and Human Needs reports that the typical American diet consists of 42% fat and a majority of that is saturated fat. However, as nutritionist Walter Willett of Harvard University recently noted, the "amount" of fat we eat is less critical to our health than the "type" of fat we eat. He explains that eating monounsaturated fat (olive oil) is good for us, but eating high levels of saturated and trans fats adds not only pounds but can also ruin our health. He cites his research on trans fat by saying, "This kind of fat is found in many kinds of margarine and other foods, especially fast food". Trans fats, he points out, are created by hydrogenating vegetable oils and are the most commonly used types because they are inexpensive, add texture and taste to commercially prepared foods, and keep fired foods from going stale. By comparison, our ancient foraging ancestors ate meat containing mostly the healthy-type of unsaturated fats and their total daily calories from fat were rarely more than 20%.

It is both the total amount of fat, and the high percentage of saturated and trans fats, that makes our modern diets so unhealthy. In addition to straining our heart and skeletal system, elevating our blood cholesterol levels, and increasing our chances of developing high blood pressure, being overweight is also the main cause for the recent rise in the number of people suffering from diabetes. Recent research has also linked being overweight with increased chances of developing a variety of cancers including prostate, breast, and colon cancer.

Dr. Boyd Eaton writes in his book, The Paleolithic Prescription that he doubts our ancient ancestors ever had to worry about coronary heart disease, one of today's major killers, especially in the world's more developed countries. High levels of serum cholesterol, diet, age, sex, and genetics are all potential contributors to coronary atherosclerosis, yet, of these, we can potentially control only several, the food we eat and the levels of serum cholesterol.

Many people mistakenly believe that their serum cholesterol level is directly linked to the amount of cholesterol they eat. Ironically, a high cholesterol diet usually only slightly raises a person's serum cholesterol level. For example, the cattle herding Masai tribe of east Africa drink large amounts of milk and have a daily intake of cholesterol that often exceeds 1,000-2,000 mg. However, most Masai warriors have low serum cholesterol levels of only 115-145 mg/dl, far less than the level of 200 that is recommended by most American doctors.

Like the Masai, our ancient ancestors probably had low serum cholesterol levels even though we suspect they may have consumed up to 1,000 mg of cholesterol daily, depending on their meat supply. Recent research confirms that genetics and a high fat diet--especially one high in saturated and trans fats--have a much greater influence on raising serum cholesterol levels than does the amount of cholesterol a person eats.

Salt: Mammals normally consume more potassium than sodium (table salt is about 40% sodium). Dr. Henry Blackburn, a professor of physiology at the University of Minnesota's Medical School, points out that the human kidney is a marvelous organ for maintaining the delicate balance between sodium and potassium in. However, because humans first developed in Africa where sodium has always been scarce, our kidneys were designed to retain, not excrete sodium.

One of the greatest changes in human diets from ancient times to the present has been the switch from ancient diets rich in potassium and low in sodium, to modern diets high in salt. A typical prehistoric forager's diet of 3,000 calories, coming 60% from fresh plant foods (leaves, nuts, tubers, berries, fruits) and 40% from meat (large game, birds, fish, eggs, reptiles) would contain about 7,000 mg of potassium and 900 mg of sodium. By comparison, the U.S. National Academy of Sciences Food and Nutrition Board reports that the average American is now consuming 6000-18,000 mg of salt per day. That, they say, is about 6-10 times too much sodium in the typical American diet that already lacks sufficient potassium.

Medical researchers believe that high sodium use, especially among people who have a genetic predisposition to retain much of the sodium they eat, is a primary cause of high blood pressure. Years ago some believed that the high levels of salt use in our diets resulted from a human craving for sodium. Today, most medical doctors believe that our salty diets are based strictly on an acquired taste, not on any type of physiological need.

Additional evidence links high blood pressure with high levels of salt use. Statistics reveal that the incidence of high blood pressure is greatest in countries with the highest per capita consumption of salt. Likewise, problems of high blood pressure do not seem to exist among many cultures with diets that are traditional low in salt and high in potassium, such as the diets of the Yanomami of Venezuela, the Inuit of the Arctic, the San of the African Kalahari, and natives in areas of Polynesian that have not been affected by tourism. I believe the evidence is overwhelming. One reason our ancient ancestors were so healthy is that they were free from the health problems caused by high blood pressure because their potassium-rich diets contained little salt.

Exercise: Another important difference between our ancient ancestors and modern populations is exercise. Hunting and gathering are activities that require strength and stamina. Hunters often travel long distances in search of game. Once game was killed and butchered, the hunters would carry the meat back to camp. Meanwhile, women spent their days digging for tubers, carrying young children, gathering other foods, finding water, and collecting firewood. Studies of modern foraging groups reveal those types of daily activities will ensure that individuals remain strong, retain great stamina, and will be slim even into their old age. Similar proof comes from the study of skeletons belonging to our ancient ancestors. Their weight-bearing leg bones and arm bones are thick and have pronounced rough areas where large muscles and tendons attached.

Once humans turned to farming their skeletons reveal that they lived a less strenuous lifestyle. Skeletons dating from the early farming era about 10,000 years ago begin to lose these robust features, and skeletons from the period of early urbanization reveal that these robust features are almost entirely gone. The evidence suggests that even though early farmers may have worked long hours, their efforts no longer required the levels of physical stamina and endurance common in the lives of pre-agricultural cultures. As, human strength was replaced by machines after the Industrial Revolution many people, especially those of the affluent classes, enjoyed a life of leisure requiring little physical effort, stamina, or strength.

During the 1960s, muscular strength and endurance testing of high school and college-age Americans revealed they were considerably weaker than earlier generations at their same age. Much of this resulted from children having fewer opportunities in daily life to burn calories. In recent years some schools have reduced physical education activities, fewer children now walk to and from school, and even today's household chores are assisted by labor-saving machines. Studies conducted in 1997 reveal that children between the ages of 6-18 are now spending an average of 38 hr/wk playing video games or watching TV. The link between adults and exercise has also been declining. As a nation, Americans walk less and drive more and most now work in facilities that are increasingly automated.

The Future

These chilling comparisons can depress us, or we can benefit from what we have learned. Until recently, medical professionals believed the degenerative process, seen in many of today's elderly, was a normal part of the aging process. However, the skeletal remains of our ancient ancestors and current medical evidence suggest that most of our degenerative processes are caused by a lifetime of neglect caused from years of eating the wrong foods and minimal exercise.

We don't have to give up the blessings of civilization, but we do need to live in harmony with our body's physiology. By selecting a diet that approximates the proportions of fats, fiber, protein, and complex carbohydrates eaten by our ancient ancestors, and by reducing our intake of sugar and sodium, we can benefit from eating a near "perfect" diet. Then, by adding regular exercise and avoiding tobacco and other harmful substances, we should be able to maintain good health with reasonable levels of strength and stamina as we age.

This doesn't mean we have to eat insects, mice, and coarse plant fibers, as our ancient ancestors once did. But, it does mean we need to make intelligent decisions at the grocery store or when we eat out in restaurants. We can reject most fried foods and instead eat broiled chicken, turkey, and fish, which are high in protein and low in fats. Most lean, red meats are high in both. Many fruits and fresh vegetables are rich in potassium and low in sodium, but their canned equivalents are often high in both sodium and sugars. Whole wheats and bran are rich in bulk and fiber while foods from refined flour are not.

If we are willing to make some dietary changes, if we try to exercise daily, and if we can balance the total number of calories we eat with the amount we burn, then we can enjoy the best aspects of the "perfect" foraging lifestyle as well as all the comforts of modern civilization.

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Note: This item orginally appeared in CAP Newsletter 25(2):8-15, 2002.