In the Paleo Diet, you're protected from protein toxicity, too-by unlimited access to fresh fruits and vegetables. You're also protected by the good cholesterol-lowering monounsaturated fats and by our most powerful deterrent to heart disease-omega 3 fatty acids. With these safeguards in place, protein is your friend. High levels of protein speed up your metabolism, reduce your appet.i.te, and lower your cholesterol. You will benefit from eating lean protein at every meal. I can a.s.sure you that as long as you eat plenty of fresh fruits and vegetables, there is no such thing as too much protein.

Restoring the Balance in Your Diet My research team and I have found that, ideally, a little more than half-55 percent-of your calories should come from lean meats, organ meats, fish, and seafood. The balance should come from fresh fruits and vegetables, some nuts, and healthful oils.

In the average American diet, not only is the balance of plant to animal food off-kilter, it's almost exactly the opposite of what we are genetically programmed to eat. In the typical American diet, 24 percent of the calories come from cereals, 11 percent from dairy products, 18 percent from refined sugars, and 18 percent from refined oils. These foods represent 71 percent of the energy consumed in the typical American diet-yet virtually none of them are to be found on the Paleo menu of lean meats, fresh fruits, and vegetables. In the American diet, about 38 percent of the calories come from animal foods, most of them high-fat and unhealthy meats (hot dogs, fatty ground beef, bacon, lunch meats, etc.)-a far cry from the Paleo Diet.

How "Progress" Has Hurt Us The Agricultural Revolution changed the world and allowed civilization-cities, culture, technological and medical achievements, and scientific knowledge-to develop. These were all good things. And yet, there was a huge downside. The Agricultural Revolution is also responsible for much of today's obesity and chronic disease. The foods that agriculture brought us-cereals, dairy products, fatty meats, salted foods, and refined sugars and oils-proved disastrous for our Paleolithic bodies.

n.o.body could have antic.i.p.ated this revolution or its consequences. The early farmers didn't have some great plan to overthrow the old system. They were just looking for better ways to feed their families in the face of a rising population and dwindling food resources. It all started in the Middle East about 10,000 years ago, when some enterprising people started to sow and harvest wild wheat seeds. Later, they domesticated barley and a few legumes and then livestock-sheep, goats, and pigs. They still picked wild fruits and vegetables and still hunted wild game, but the die was cast; the diet had changed dramatically.

h.e.l.lo Grains, h.e.l.lo Health Problems The archaeological record clearly shows that whenever and wherever ancient humans sowed seeds (and replaced the old animal-dominated diets), part of the harvest included health problems. One physical ramification of the new diet was immediately obvious: early farmers were markedly shorter than their ancestors. In Turkey and Greece, for example, preagricultural men stood 5 feet 9 inches tall and women 5 feet 5 inches. By 3000 B.C., the average man had shrunk to 5 feet 3 inches and the average woman to 5 feet. But getting shorter-not in itself a health problem-was the least of the changes in these early farmers. Studies of their bones and teeth have revealed that these people were basically a mess: they had more infectious diseases than their ancestors, more childhood mortality, and shorter life spans in general. They also had more osteoporosis, rickets, and other bone mineral disorders, thanks to the cereal-based diets. For the first time, humans were plagued with vitamin- and mineral-deficiency diseases-scurvy, beriberi, pellagra, vitamin A and zinc deficiencies, and iron-deficiency anemia. Instead of the well-formed, strong teeth their ancestors had, there were now cavities. Their jaws, which were formerly square and roomy, were suddenly too small for their teeth, which overlapped each other.

What had gone wrong? How could the benign practice of agriculture-harnessing nature's bounty-have caused so many health problems? We now know that although the population was soaring, the quality of life-as well as the average life span-was in a nosedive. The new staples, cereals and starches, provided calories but not the vital nutrients of the old diet-lean meats, fruits, and vegetables. The result-ill health and disease.

The health picture got worse over the years with the arrival of salt, fatty cheeses, and b.u.t.ter. Our ancestors learned to ferment grains, make beer, and eventually distill spirits. Selective breeding-and the innovation of feeding grain to livestock-steadily produced fatter pigs, cows, and sheep. Most meat wasn't eaten fresh-fewer people hunted-but instead was pickled, salted, or smoked. Fruits and vegetables became luxuries-rare seasonal additions to the monotony of cereal and starch.

More recently-just 200 years ago-the Industrial Revolution brought refined sugar, canned foods, and refined white flour to the average family's table. Food was processed in earnest by the mid-twentieth century with the invention of trans-fatty acids, margarine, shortening, and combinations of these fats mixed with sugar, salt, other starches, high omega 6 vegetable oils, high-fructose corn syrup, and countless additives, preservatives, coloring agents, and emulsifiers.

Imagine a Paleolithic human confronted with a Twinkie or even a pizza. He or she wouldn't even recognize these modern-day treats as food.

Big Mistakes in the 1950s In many ways, the 1950s were a simpler time. Part of the mind-set then seemed to be to find simple solutions for complicated problems. In the early 1950s, when scientists were unraveling the links between diet and heart disease, they found that saturated fat saturated fat (the kind found in b.u.t.ter, cheese, and fatty meats) raised total blood cholesterol; it also raised the LDL (the bad kind) cholesterol level and increased the risk of heart disease. More recent research has shown that not all saturated fats raise total and LDL cholesterol. Stearic acid actually lowers blood cholesterol similar to the way that monounsaturated fats do. Unfortunately, red meat became the scapegoat; all of a sudden, it was the chief artery clogger and cause of heart attacks. Even many nutritionists and physicians jumped to the conclusion that red meat was an unhealthy food that promoted heart disease and bowel cancer. (the kind found in b.u.t.ter, cheese, and fatty meats) raised total blood cholesterol; it also raised the LDL (the bad kind) cholesterol level and increased the risk of heart disease. More recent research has shown that not all saturated fats raise total and LDL cholesterol. Stearic acid actually lowers blood cholesterol similar to the way that monounsaturated fats do. Unfortunately, red meat became the scapegoat; all of a sudden, it was the chief artery clogger and cause of heart attacks. Even many nutritionists and physicians jumped to the conclusion that red meat was an unhealthy food that promoted heart disease and bowel cancer.

The food industry responded to the message that saturated fats were bad by creating all sorts of "healthy alternatives"-highly polyunsaturated vegetable oils (corn, safflower, sunflower, and cottonseed, to name a few). They also gave us all kinds of products made from these oils, such as margarines, shortening, spreads, and dressings. And almost overnight, these vegetable oils and their spin-offs were incorporated into virtually all processed foods and baked goods.

Unfortunately, as we now know, this was a very bad move. The indiscriminate infusion of vegetable oils into the American diet gave us far too many omega 6 polyunsaturated fats at the expense of the good omega 3 polyunsaturated fats. And the increased use of margarine and spreads caused the widespread introduction of still another kind of fat, called "trans-fatty acids," into our meals and snacks.

The next plan the nutritional masterminds came up with-like the anti-red meat campaign, it was not well thought out and was inadequately tested before being put into practice-was to replace saturated fats with carbohydrates, primarily starchy carbohydrates, like those found in bread, potatoes, and cereals. By the early 1990s, this recommendation had become so entrenched that it was the official policy of the USDA. The bedrock of our national Food Pyramid is its base-six to eleven servings of cereal grains. We now know, from scientific studies examining something called the "glycemic index" of certain foods, that this is six to eleven servings too many.

Part of the confusion here is that all carbohydrates are not created equal. Some of them are good for us. But others promote ill health and disease, and this brings us to the glycemic index. Good carbohydrates have a low glycemic index. This means they cause a minimal or slow rise in our blood glucose (sugar) level. The "glycemic load" is the glycemic index of a food times its carbohydrate content. It is this high-glycemic load that elevates blood insulin levels in many people. High-glycemic carbohydrates cause large and rapid rises in blood glucose and have been implicated in a wide variety of chronic diseases-adult-onset diabetes, high blood pressure, heart disease, obesity, elevated blood uric acid levels, elevated blood triglycerides (the building blocks of fat, which float around in the bloodstream), elevated small-dense LDL cholesterol, and reduced HDL cholesterol. This cl.u.s.ter of diseases is known to cardiologists as metabolic syndrome. Regrettably, the architects of the Food Pyramid did not distinguish between high- and low-glycemic carbohydrates when they started this carbomania.

Let's see how our modern way of eating has deviated from the Seven Keys to nutrition I laid out in chapter 2, and how this has affected our health.

The Seven Major Problems in the Typical American Diet 1. Not Enough Protein Protein makes up 15 percent of the calories that most Americans (and people in other Western countries) eat every day. But it should be much higher-between 19 and 35 percent-to give us more energy and help us burn off extra calories. Look at the numbers: For every 100 calories, cereals average only about 12 percent protein-compared to 83 percent protein for game meats. Legumes like lentils, peas, and beans average 27 percent protein.

As for dairy products, the phenomenon of the "milk cow" (or goat or sheep) happened roughly 9,000 years ago. Milk contains 21 percent protein, cheese averages 28 percent protein, and b.u.t.ter has absolutely no protein-but a lot of fat.

The bottom line: Most of us are getting only half of the protein we need. Why is this bad? As I'll discuss in the next three chapters, a low protein intake contributes to weight gain and a high blood cholesterol level and increases your risk of many chronic diseases. Why is this bad? As I'll discuss in the next three chapters, a low protein intake contributes to weight gain and a high blood cholesterol level and increases your risk of many chronic diseases.

2. Too Much of the Wrong Carbohydrates The USDA Food Pyramid is based on carbohydrates; we're a nation of starch and sugar eaters. Carbohydrates make up about half of the typical Western diet-a considerable difference from the Paleo Diet. For our ancient ancestors, carbohydrates accounted for 22 to 40 percent of the daily calories-but these were good carbohydrates, from wild fruits and vegetables. These low-glycemic foods-which don't cause blood sugar to spike-are digested and absorbed slowly.

With nonstarchy fruits and vegetables, it's very hard to get more than about 35 percent of your calories as carbohydrates. For example: There are 26 calories in the average tomato. To get 35 percent of your daily calories as carbohydrates from tomatoes only, you'd have to eat thirty tomatoes. And this is why, with the Paleo Diet, you can indulge yourself by eating all the nonstarchy fruits and vegetables you want. When you eat the right foods, getting too many carbohydrates-or eating too many high-glycemic carbohydrates, which can cause a dangerous rise in your blood sugar and insulin levels-is simply not something you have to worry about. The average carbohydrate content of fruits is only about 13 percent per 100 grams, about 4 percent for nonstarchy vegetables-and zero for lean meats, fish, and seafood. In stark contrast, the average carbohydrate content of cereal grains is 72 percent per 100 grams.

Why are many carbohydrates bad? Many whole grains and legumes don't have a lot of vitamins and minerals. They're poor dietary sources of these important nutrients. So a diet that's tilted too heavily toward grains and legumes-at the expense of lean meats, fruits, and vegetables-can lead to vitamin and mineral deficiencies. This is why so many of our breads and cereals are fortified with extra nutrients. Food shouldn't need to be supplemented with vitamins, and if you're getting the right balance of lean meats, fruits, and vegetables, neither should you.

Worse, cereal grains and legumes even contain "antinutrients"-chemicals that actually prevent prevent your body from absorbing the proper nutrients and can damage the gastrointestinal and immune systems. Too many grains and legumes can disrupt the acid balance in the kidneys as well, and can contribute to the loss of muscle ma.s.s and bone mineral content with aging. your body from absorbing the proper nutrients and can damage the gastrointestinal and immune systems. Too many grains and legumes can disrupt the acid balance in the kidneys as well, and can contribute to the loss of muscle ma.s.s and bone mineral content with aging.

Finally, if you eat more carbohydrates, you're eating less protein. Protein is the dieter's friend: it reduces your appet.i.te and increases your metabolism-and this translates rapidly into weight loss.

One of the great dietary myths in the Western world is that whole grains and legumes are healthful. The truth is that these foods are marginal at best. But what about the "health-food" breads? At best, they're less bad less bad than the overprocessed, super-refined white breads you could be buying. But they're still not part of the Paleo Diet. Formerly (before "progress" brought refined milling technology to bread making), almost all cereal grains either were eaten whole or were so crudely milled that nearly the entire grain-bran, germ, and fiber-remained intact, and flour was much less refined than the kind we buy today. Our great-greatgrandparents ate cracked wheat breads and baked goods with a moderate glycemic index-which meant a more moderate rise in blood sugar level. than the overprocessed, super-refined white breads you could be buying. But they're still not part of the Paleo Diet. Formerly (before "progress" brought refined milling technology to bread making), almost all cereal grains either were eaten whole or were so crudely milled that nearly the entire grain-bran, germ, and fiber-remained intact, and flour was much less refined than the kind we buy today. Our great-greatgrandparents ate cracked wheat breads and baked goods with a moderate glycemic index-which meant a more moderate rise in blood sugar level.

Does this mean that whole grains are good for you? Not necessarily. It just means that an extra bad characteristic-a high glycemic index-wasn't incorporated into them yet. That unfortunate addition happened about 130 years ago, when steel roller mills came on the flour-making scene. They smashed all the fiber out of the grains and left the wimpy white, high-glycemic powder most of us think of as flour. Today, almost all baked goods made with this stuff frequently cause the blood sugar level to rise excessively.

Even "whole wheat" bread made from flour ground by these steel roller mills does the same thing to your blood sugar, because the flour particle size is uniformly small-so it's virtually no different from white flour. About 80 percent of all the cereal products Americans eat-as they follow the directions of the USDA Food Pyramid-come from refined white flour with a high glycemic index.

Cereal grains are literally best left for the birds Compounding the Problem: Sugar and Sweeteners Our Paleolithic ancestors loved honey. But it was a rare treat, because it was only available seasonally and in limited quant.i.ties (and they had to outmaneuver bees to get it). So for the most part, refined sugars-another source of carbohydrates-simply were not part of humanity's diet for 2.5 million years. In fact, until about the last 200 years or so, they weren't part of anybody's diet.

Sugar is another of those side effects of technological "progress," and its rise to prominence in our daily life has been rapid. In England in 1815, the average person used about 15 pounds of table sugar a year; in 1970, the average person used 120 pounds. How much sugar do you buy a year? Do you buy another 5-pound bag every time you go to the grocery store? You're not alone.

Yet sugar, like refined cereal grains, is not good for us. Sure, it causes cavities-most of us hear that message every time we go to the dentist. But it's also becoming evident that sugar poses more serious health problems. It promotes insulin resistance and metabolic syndrome diseases almost as much as high-glycemic breads and starchy potatoes do.

The chemical name for table sugar is "sucrose." Although sucrose has nearly the same high glycemic index (65) as white bread (70), it has two additional characteristics that make it particularly harmful for insulin metabolism. First, it is 100 percent carbohydrate, meaning that its glycemic load is very high.

Second, when your body digests sucrose, it is broken down into two simple sugars-high-glycemic glucose (with a glycemic index of 97) and low-glycemic fructose (with a glycemic index of 23). Scientists used to think that fructose was not harmful because of its low glycemic index. But recent laboratory studies by Dr. Mike Paglia.s.sotti and colleagues at Arizona State University have revealed that fructose is actually the main culprit in table sugar that causes insulin resistance. Dr. Paglia.s.sotti's findings were bolstered by research at the University of Lausanne Medical School in Switzerland, by Dr. Luc Tappy and colleagues, showing that fructose can cause insulin resistance in humans. Insulin resistance, in turn, often promotes obesity and chronic metabolic syndrome diseases, including hypertension, heart disease, and diabetes.

To calculate the glycemic load, multiply the glycemic index by the carbohydrate content High-Fructose Corn Syrup: A Really Bad Idea The steady increase in table sugar use was an unfortunate development in the carbohydrate content of our diet. But in the 1970s, the food-processing industry made a discovery: high-fructose corn syrup could save them a lot of money. Because fructose is so much sweeter than sucrose, less of it is needed to sweeten any processed food. Today corn syrup is the food-processing industry's sweetener of choice. Imagine the financial incentive here: with fructose, millions of tons of sugar are saved each year.

What does this mean to average Americans? It means we are getting grossly disproportionate amounts of sweetener in our diets. There are about 10 teaspoons of high-fructose corn syrup in a single 12-ounce can of soda. 10 teaspoons of high-fructose corn syrup in a single 12-ounce can of soda. The average American now eats 66 pounds of corn syrup a year, plus 64 pounds of sucrose, and an appalling total of 131 pounds of refined sugars. When you begin the Paleo Diet and gradually wean yourself off processed foods, your daily sugar intake will drastically shrink-and, better still, the sugar you get will come from healthful fruits and vegetables. The average American now eats 66 pounds of corn syrup a year, plus 64 pounds of sucrose, and an appalling total of 131 pounds of refined sugars. When you begin the Paleo Diet and gradually wean yourself off processed foods, your daily sugar intake will drastically shrink-and, better still, the sugar you get will come from healthful fruits and vegetables.

3. Not Enough Fiber Fiber intake began to go down the day our ancient ancestors started harvesting cereal grains. How can this be? Don't whole grains equal fiber? When our doctors tell us to add more fiber to our diet, don't they mean for us to eat more oatmeal? The truth is that calorie for calorie, whole grains can't hold a candle to fruits and vegetables. Fruits on average contain almost twice as much almost twice as much fiber as whole grains. Compared to whole grains, nonstarchy vegetables have fiber as whole grains. Compared to whole grains, nonstarchy vegetables have eight times more fiber. eight times more fiber. Sugars have absolutely no fiber. Sugars have absolutely no fiber.

And yet we know that dietary fiber is absolutely essential for good health. Not having enough fiber raises our risk of developing scores of diseases and health problems. A comprehensive medical text edited by Drs. Hugh Trowell, Denis Burkitt, and Kenneth Heaton has implicated low dietary fiber in the following diseases and health problems: constipation, diverticulitis, colon cancer, appendicitis, Crohn's disease, ulcerative colitis, irritable bowel syndrome, duodenal ulcer, hiatal hernia, gastroesophageal reflux, obesity, type 2 diabetes, gallstones, high blood cholesterol, varicose veins, hemorrhoids, deep vein thrombosis, and kidney stones.

4. Too Much Fat and Too Many Bad Fats Cut the fat! If the nutritional experts have had an overriding message over the last decades, this is it.

The thing is, this dictum is flat-out wrong. We now know that it's not how much how much fat you eat that raises your blood cholesterol levels and increases your risk of heart disease, cancer, and diabetes-it's the fat you eat that raises your blood cholesterol levels and increases your risk of heart disease, cancer, and diabetes-it's the kind kind of fat you eat. We consume too many omega 6 polyunsaturated fats at the expense of the healthful omega 3 kind. And we get plenty of those cholesterol-raising, artery-clogging trans-fatty acids found in margarine, shortening, and many processed foods. Finally, we eat excessive amounts of palmitic acid, a blood cholesterol-raising saturated fat found in cheeses, baked goods, and fatty processed meats, such as hot dogs, bacon, bologna, and salami. of fat you eat. We consume too many omega 6 polyunsaturated fats at the expense of the healthful omega 3 kind. And we get plenty of those cholesterol-raising, artery-clogging trans-fatty acids found in margarine, shortening, and many processed foods. Finally, we eat excessive amounts of palmitic acid, a blood cholesterol-raising saturated fat found in cheeses, baked goods, and fatty processed meats, such as hot dogs, bacon, bologna, and salami.

All of those kinds of fat are bad and need to go. But in removing all fats from our diet, we are doing more harm than good. This problem is easy to solve: With the Paleo Diet-which contains healthful fats-you will automatically reestablish the proper balance of fats in your diet. You'll also lower your blood cholesterol and reduce your risk of heart disease, cancer, and other chronic illnesses.

From our a.n.a.lyses of the fats in wild animals, my research team and I have found that even though ancient humans ate meat at nearly every meal, they consumed about half of the palmitic acid found in the average Western diet. (Wild game meat is low in total fat and palmitic acid and high in healthful, cholesterol-lowering monounsaturated fat and stearic acid.) They also ate lots of omega 3 polyunsaturated fats.

See Appendix 2 for a table contrasting the fats in domestic and wild meats.

The ratio of omega 6 to omega 3 fats in Paleo diets was about 2 to 1; for the average American, the ratio is much too high-about 10 to 1. Eating too many omega 6 fats instead of omega 3 fats increases your risk of heart disease and certain forms of cancer; it also aggravates inflammatory and autoimmune diseases. The lean meats, fish, fruits, vegetables, and oils found in the Paleo Diet guarantee that you will have the proper ratio of omega 6 and omega 3 fats-and of all other fats.

Cereal Doesn't Help Cereal grains are low in fat. But the little fat they do have is unbalanced-tilted heavily toward omega 6. For example, in game and organ meat, the average ratio of omega 6 to omega 3 is 2 or 3 to one. In eight of the world's most commonly consumed cereals, this ratio is a staggering 22 to 1.

Cereal grains also have contributed to generations of blubbery cows that bear little resemblance to the lean wild animals our ancestors ate. Grain-fed cows have become loaded down with palmitic acid; worse, the fats in their meat have taken on the same high omega 6 to omega 3 ratio that's in their grain.

Milk Doesn't Help, Either Dairy foods have taken a further toll on humanity's health over the last 9,000 years or so. Milk, cream, cheese, b.u.t.ter, and fermented milk products (including yogurt), ice cream, and the many processed dairy products of the twentieth century are some of the richest sources of certain saturated fats in the typical Western diet. In particular, fatty dairy foods contain palmitic and myristic fatty acids-two substances that elevate blood cholesterol. When you evaluate dairy products for fat percentage by calories, b.u.t.ter is the worst at 100 percent fat. Cream is 89 percent fat, cheeses average about 74 percent fat, and whole milk is about 49 percent fat. And most of the fats in these dairy products-about 40 percent-are the bad saturated fatty acids. Despite their wholesome image, whole milk and fatty dairy products are some of the least healthful foods in our diets. Their fatty acids (palmitic acid and myristic acid) raise your blood cholesterol; they also raise your risk of developing heart disease and other chronic illnesses.

The Trouble with Unbalanced Vegetable Oils The next major misstep in food innovation happened just a few decades ago, when vegetable oils became part of our diet.

In the 1940s and 1950s, when most of these vegetable oils were introduced, n.o.body realized that the ratio ratio of omega 6 to omega 3 fats was terribly important to health. What food scientists knew at that point was pretty simple-that polyunsaturated fats lowered blood cholesterol. And it was with this limited piece of the total picture that they happily created a great variety of cooking and salad oils that were highly polyunsaturated-but regrettably also extremely high in omega 6 fats. The worst offenders are safflower oil and peanut oil (with extremely high omega 6 to omega 3 ratios), cottonseed oil, sunflower oil, sesame oil, and corn oil. Walnut oil is more balanced. And flaxseed oil is better still-low in omega 6 fats and high in omega 3. of omega 6 to omega 3 fats was terribly important to health. What food scientists knew at that point was pretty simple-that polyunsaturated fats lowered blood cholesterol. And it was with this limited piece of the total picture that they happily created a great variety of cooking and salad oils that were highly polyunsaturated-but regrettably also extremely high in omega 6 fats. The worst offenders are safflower oil and peanut oil (with extremely high omega 6 to omega 3 ratios), cottonseed oil, sunflower oil, sesame oil, and corn oil. Walnut oil is more balanced. And flaxseed oil is better still-low in omega 6 fats and high in omega 3.

Trans Fats Are Terrible Cooking and salad oils are just part of the high omega 6 problem. Nearly all processed foods-breads, cookies, cakes, crackers, chips, doughnuts, m.u.f.fins, cereals, and candies-and all fast foods are cooked with some form of high omega 6 vegetable oil. Worse, many of these foods are still made with hydrogenated vegetable oils that contain harmful trans-fatty acids. Trans fats raise blood cholesterol and increase your risk of developing heart disease. A study published in the American Journal of Public Health American Journal of Public Health concluded that consumption of trans fats by Americans was responsible for more than 30,000 deaths annually from heart disease. Trans fats are found in margarine, shortening, and some peanut b.u.t.ters-foods that definitely were not part of humanity's original diet. concluded that consumption of trans fats by Americans was responsible for more than 30,000 deaths annually from heart disease. Trans fats are found in margarine, shortening, and some peanut b.u.t.ters-foods that definitely were not part of humanity's original diet.

5. Too Much Salt, Not Enough Pota.s.sium Paleo diets were exceptionally rich in pota.s.sium and low in sodium. Just about everything Paleolithic people ate-meats, fish, fruits, vegetables, nuts, and seeds-contained about five to ten times more pota.s.sium than sodium. This means that when you eat only fresh, unprocessed food, it's impossible to consume more sodium than pota.s.sium.

We don't know exactly when farmers began to include salt in their diet, but we can guess why. Salt performed a great service, in the centuries before refrigeration, in preserving meats and other foods. It helped make foods like olives edible; it added flavor to bland cereals and other foods. At least 5,600 years ago, archaeological evidence shows us, salt was mined and traded in Europe. It remains a staple today; in fact, the average American consumes about twice as much sodium as pota.s.sium. And that's not healthy.

6. An Acid-Base Imbalance Very few people-including nutritionists and diet.i.tians-are aware that the acid-base content of your food can affect your health. Basically, this is what happens: everything you digest eventually reports to the kidneys as either an acid or an alkaline base. Acid-producing foods are meats, fish, grains, legumes, dairy products, and salt. Alkaline-producing foods are fruits and vegetables. You need both kinds-acid and alkaline. Fats are generally neutral.

The average American diet is slightly acidic-which means that our kidneys must handle a net acid load. For example: Suppose you have a typical "light" lunch, probably available at a dozen places near your home or office, of pepperoni pizza and a small salad with Caesar dressing. This meal is a disaster for the body's acid-base balance: the pizza's white-flour crust, melted cheeses, and salty pepperoni are all highly acidic. Add salt, and you make it even more acidic. Any alkaline remnant available in the tiny salad is neutralized by the salt and cheese in the Caesar salad dressing.

In the long run, eating too many acid foods and not enough alkaline foods can contribute to bone and muscle loss with aging. There are more immediate dangers, too: excessive dietary acid can raise blood pressure and increase your risk of developing kidney stones. It can also aggravate asthma and exercise-induced asthma.

7. Not Enough Plant Phytochemicals, Vitamins, Minerals, and Antioxidants The Paleo Diet is rich in vitamins and minerals. One of the best ways to prove how healthy our diet used to be is to show what happened when our ancestors fiddled with it.

Vitamin C deficiency, a disease unknown to Paleolithic people, causes scurvy. Paleolithic people didn't have this problem; their diets were extremely high in vitamin C (around 500 milligrams per day) because they ate so many fresh fruits and vegetables. But even Eskimo groups-who for thousands of years have eaten virtually no plant foods for most of the year-didn't get scurvy. How can this be? They got their vitamin C from other natural sources-raw fish, seal, and caribou meat. a disease unknown to Paleolithic people, causes scurvy. Paleolithic people didn't have this problem; their diets were extremely high in vitamin C (around 500 milligrams per day) because they ate so many fresh fruits and vegetables. But even Eskimo groups-who for thousands of years have eaten virtually no plant foods for most of the year-didn't get scurvy. How can this be? They got their vitamin C from other natural sources-raw fish, seal, and caribou meat.

But as our ancestors began eating more cereal grains and fewer lean meats, fresh fruits, and vegetables, they lost much of the vitamin C in their diets. Cereal grains have no vitamin C, which is one of the body's most powerful antioxidants. Vitamin C helps lower cholesterol, reduces the risk of heart disease and cancer, boosts the immune system, and helps ward off infections and colds.

Vitamin A deficiency, like scurvy, could only have emerged after the coming of agriculture. Paleo diets were always rich in fruits and vegetables-excellent sources of beta-carotene, a nutrient that can be converted to vitamin A by the liver. (Our ancient ancestors also ate the entire carca.s.ses of the animals they hunted and killed, including the vitamin A-rich liver.) Again, trouble happened when cereals took over and fresh fruits, vegetables, and organ meats were pushed aside. Vitamin A is essential for all of the body's mucous membranes. Vitamin A deficiency results in a condition called "xerophthalmia" (dry eyes), which can lead to blindness; in fact, this is the leading cause of blindness in children worldwide. Vitamin A deficiency also impairs the body's ability to fight infection and disease. like scurvy, could only have emerged after the coming of agriculture. Paleo diets were always rich in fruits and vegetables-excellent sources of beta-carotene, a nutrient that can be converted to vitamin A by the liver. (Our ancient ancestors also ate the entire carca.s.ses of the animals they hunted and killed, including the vitamin A-rich liver.) Again, trouble happened when cereals took over and fresh fruits, vegetables, and organ meats were pushed aside. Vitamin A is essential for all of the body's mucous membranes. Vitamin A deficiency results in a condition called "xerophthalmia" (dry eyes), which can lead to blindness; in fact, this is the leading cause of blindness in children worldwide. Vitamin A deficiency also impairs the body's ability to fight infection and disease.

Vitamin B deficiency is another problem. Many people believe that whole-grain cereals are rich sources of B vitamins. They're mistaken. Compared to lean meats, fruits, and vegetables, calorie for calorie, cereals are vitamin B lightweights. Even worse, as I mentioned earlier, whole grains and legumes contain antinutrients that block the absorption of B vitamins in the intestines. For instance, antinutrients called "pyridoxine glucosides" can prevent your body from getting as much as two-thirds of the vitamin B is another problem. Many people believe that whole-grain cereals are rich sources of B vitamins. They're mistaken. Compared to lean meats, fruits, and vegetables, calorie for calorie, cereals are vitamin B lightweights. Even worse, as I mentioned earlier, whole grains and legumes contain antinutrients that block the absorption of B vitamins in the intestines. For instance, antinutrients called "pyridoxine glucosides" can prevent your body from getting as much as two-thirds of the vitamin B6 you eat. In a study of vegetarian women from Nepal, Dr. Robert Reynolds, of the USDA Human Nutrition Research Center, linked the low vitamin B you eat. In a study of vegetarian women from Nepal, Dr. Robert Reynolds, of the USDA Human Nutrition Research Center, linked the low vitamin B6 levels in these women to the high levels of pyridoxine glucosides in their grain- and legume-heavy diets. In contrast, the availability of vitamin B levels in these women to the high levels of pyridoxine glucosides in their grain- and legume-heavy diets. In contrast, the availability of vitamin B6 in lean meats is nearly 100 percent. in lean meats is nearly 100 percent.

Another B vitamin that's poorly absorbed when you eat whole grains is biotin. Experiments by my colleague Dr. Bruce Watkins from Purdue University have shown that wheat and other whole grains impair the body's ability to get enough biotin. Biotin deficiencies result in dry, brittle fingernails and hair. Research by Dr. Richard K. Scher and colleagues at Columbia University has shown that biotin supplements reduce fingernail brittleness and vertical "ridging" in nails. But you won't need to supplement your diet if you get enough biotin (or any other vitamin or mineral) the old-fashioned way-by eating the right foods. The availability of biotin from animal foods is almost 100 percent.

Pellagra and beriberi are two of the most devastating and widespread B vitamin deficiency diseases that have ever plagued human-kind. They are caused exclusively by excessive consumption of cereals. Pellagra is a serious, often fatal, disease caused by a lack of the B vitamin niacin and the essential amino acid tryptophan. In a sad chapter of U.S. history, between 1906 and 1940 there was an epidemic of pellagra in the South. An estimated 3 million people developed it, and at least 100,000 of them died. Similar outbreaks have occurred in Europe and India, and pellagra is still common in parts of Africa.

Underlying every worldwide pellagra epidemic was excessive consumption of corn. Corn has low levels of both niacin and tryptophan, and the tiny amounts of niacin that are present are poorly absorbed. Pellagra could never have happened in the Paleolithic era, because lean meats are excellent sources of both niacin and tryptophan. Invariably, whenever we stray from the lean meats, fruits, and vegetables that we are genetically adapted to eat, ill health is the result.

Beriberi, caused by a deficiency of vitamin B1 (thiamin), ultiately causes paralysis of the leg muscles. This disease was virtually unknown until the introduction of polished rice in the late 1800s. In parts of j.a.pan and Southeast Asia, where rice was the staple food, beriberi became epidemic as people replaced their traditional brown rice with white rice. Eventually, scientists discovered that removing the thiamin-containing bran during the polishing process was largely responsible for this disease. Beriberi has been mostly eliminated with the introduction of "enriched" rice, to which vitamin B (thiamin), ultiately causes paralysis of the leg muscles. This disease was virtually unknown until the introduction of polished rice in the late 1800s. In parts of j.a.pan and Southeast Asia, where rice was the staple food, beriberi became epidemic as people replaced their traditional brown rice with white rice. Eventually, scientists discovered that removing the thiamin-containing bran during the polishing process was largely responsible for this disease. Beriberi has been mostly eliminated with the introduction of "enriched" rice, to which vitamin B1 is added. However, the message should be clear: If we have to add 1 a vitamin to a food to prevent it from causing ill health and disease, we shouldn't be eating it in the first place. is added. However, the message should be clear: If we have to add 1 a vitamin to a food to prevent it from causing ill health and disease, we shouldn't be eating it in the first place.

Vitamin B Deficiency and Heart Disease In North America, we enrich our refined cereal grains with vitamin B1 and niacin-which means you will never have to worry about pellagra or beriberi. But it doesn't mean that these foods are good for you. Far from it. Within the past twenty years, a major risk factor for heart disease has surfaced. It has been found that low dietary intakes of three B vitamins-B , B and niacin-which means you will never have to worry about pellagra or beriberi. But it doesn't mean that these foods are good for you. Far from it. Within the past twenty years, a major risk factor for heart disease has surfaced. It has been found that low dietary intakes of three B vitamins-B , B12, and folate-increase your blood level of an amino acid called h.o.m.ocysteine. A high blood level of h.o.m.ocysteine, in turn, increases your risk of heart disease. Whole-grain cereals have no vitamin B12, their vitamin B is poorly absorbed, and they are at best a meager source of folate. So excessive consumption of whole-grain cereals instead of lean meats, fruits, and vegetables is a formula for disaster for your heart. Again, lean meats are rich sources of vitamins B and B , and fresh fruits and vegetables are our best food sources of folate. By eating the foods nature intended, you will never have to worry about your B vitamin status, h.o.m.ocysteine level, and heart disease.

Folate Deficiency Since most Americans don't eat enough fresh fruits and vegetables, our dietary intake of folate is often marginal or low. Folate not only protects us from heart disease, it reduces our risk of colon cancer. Taken by pregnant women, it prevents spina bifida. Because of these healthful effects, the U.S. government now enriches our refined cereal grains with folic acid (a form of folate). So, somewhat paradoxically, you can now eat white bread, doughnuts, and cookies to increase your folic acid intake-but when you eat whole grains, you won't get this benefit.

The bottom line is that grains are an inferior food. No matter how you slice your bread (whole or refined), grains are not good for you. Even when they're artificially pumped full of vitamins and minerals, they cannot measure up to lean meats, fruits, and vegetables.

Minerals On paper, whole grains appear to be a fairly good source of many important minerals, such as iron, zinc, copper, and calcium. Actually, cereals are lousy sources of these nutritionally important minerals.

Iron Remember the antinutrients that block our absorption of B vitamins? Other antinutrients, called "phytates," chemically bind iron, zinc, copper, and calcium within grains and block their absorption during digestion. Phytates do their job so well that the worldwide epidemic of iron-deficiency anemia-which affects 1.2 billion people-is universally attributed to the poor availability of iron in cereal- and legume-based diets. Iron-deficiency anemia weakens you and hinders your ability to work; it also makes you more susceptible to infection and more likely to develop a severe infection. It increases a mother's risk of dying during childbirth. It can permanently impair a child's learning ability. Iron-deficiency anemia-like the other deficiency diseases caused by agriculture's new foods-would not have been possible with Paleo diets. Lean meats and animal foods are rich sources of iron. More important, the type of iron found in lean meats and animal foods is easily a.s.similated by the body.

Zinc Zinc deficiency is another disaster caused by whole-grain cereals. In much of the Middle East, a whole-wheat flatbread called tanok contributes more than half of the total daily calories. Studies done by Dr. John Reinhold and colleagues have shown that tanok causes a zinc deficiency that stunts growth and delays p.u.b.erty in children. We need zinc to help us fight infection and colds, to sustain our strength, and to enable us to work. Once again, lean meats are excellent sources of zinc. In fact, the "bioavailability" (the amount you receive of a particular nutrient) of zinc from meat is four times greater than from grains.

Calcium Most American women, and many men, have gotten the message about calcium: insufficient dietary calcium can eventually lead to bone loss and osteoporosis. Few realize that cereal grains and legumes are a catastrophe for your bone health. As with iron and zinc, the little calcium that's present in whole grains is bound to phytates-which means that most of it never gets absorbed by the body. Cereals also contain high levels of phosphorus. We know that an unfavorable calcium-to-phosphorus ratio can speed up bone loss. Also, cereals produce a net acid load to the kidneys-and this, too, increases calcium loss in the urine.

Whole grains are even known to disrupt vitamin D metabolism in the body. Vitamin D increases calcium absorption and prevents rickets, a disease that causes bone deformities. In fact, scientists who want to study rickets in laboratory animals know exactly how to produce it-by feeding the animals whole grains. In many of the world's undeveloped countries, where whole grains and legumes are the main sources of calories, rickets, osteoporosis, and other bone-mineral diseases are common.

From the fossil record, we know that these same bone-mineral problems were also common among the first farmers. Not surprisingly, the hunter-gatherers who came before them didn't have these diseases. Hunter-gatherers never drank milk. They did not have bone-mineral problems because they ate lots of fruits and vegetables-which gave them enough calcium to build strong bones. Fruits and veggies also gave them an abundant source of alkaline base that prevented excessive losses of calcium in the urine. When you adopt the Paleo Diet, you won't have to worry about your calcium intake. You'll get all you need from the fruits and vegetables. But more important, you'll be in calcium balance. You will be taking in more calcium than you lose, and this is essential for bone health.

By restoring lean meats, fruits, and veggies to your diet and eliminating agriculture's new foods, you will lose weight, feel better, and reduce your risk of developing the diseases of civilization that plague us all.

PART TWO.

Losing Weight and Preventing and Healing Diseases

4.

Losing Weight the Paleo Diet Way.

Here are four reasons why you should make lean protein a major part of your diet: * It can't be overeaten.* It raises your metabolism, causing you to burn more calories.* It satisfies your appet.i.te, causing you to feel less hungry between meals.* It improves insulin sensitivity.

Determining Whether You Need to Lose Weight How do you know if you're overweight? Scientists have devised a simple measure based on your height and weight that allows you to know exactly how much extra weight you may be toting. This measure system is called the "body ma.s.s index" (BMI), and here are the categories:

BMI.

Cla.s.sification Below 18.5 Underweight 18.5-24.9.

Normal 25.0-29.9.

Overweight Above 30.0 Obesity

The BMI is easy to calculate. It is simply your weight in kilograms (kg) divided by your height in meters (m) squared. You can calculate your weight in kilograms by dividing your weight in pounds by 2.2. You can change your height to meters by multiplying your height in inches by 0.0254. So a 5-foot, 4-inch (64 inches) tall woman who weighs 154 pounds would weigh 70 kilograms (154 / 2.2 = 70 kg), and her height in meters would be 1.63 meters (64 0.0254 = 1.63 m). Her height in square meters would be 2.66 (1.63 1.63 = 2.66). Her BMI would be 26.3 (70 / 2.66 = 26.3). This would put her in the overweight category. If your BMI is greater than 27, this may be a sign that you are insulin resistant and have (or are at high risk of developing) one or more of the diseases of metabolic syndrome.

A Doctor Loses 30 Pounds: Ben's Story Here is what Dr. Ben Balzer, a general family physician from Sydney, Australia, has to say about the Paleo Diet: In April this year, I reached the end of my tether with my weight. I'd tipped the scales at 222 lbs. My weight for my height should be under 172 pounds. In fact, I'd been too frightened to get on the scales for some weeks, as I knew what they would tell me. I'm sure I hit 225 pounds during this time. I'd been following the standard dietary advice of low-fat dieting reasonably well for seven years. Although it worked well at first, it stopped, and my weight had gradually increased.As a doctor, I knew exactly what I was in for. I have a strong family history of diabetes, hypertension, stroke. I was 37 years old. Medically, I knew it was inevitable that I would be affected if I didn't act. I was feeling tired, bloated, and sluggish. It seemed harder to get through each day. I tried to exercise but had trouble finding the time and could swim only 500 meters with difficulty. My feet were also hurting badly. I had had heel pain syndrome (heel spur) for two and a half years, despite cortisone shots and physical therapy. I had headaches at least five days a week.Fortunately, 10 years earlier I'd heard a noted Australian professor of medicine mention the Paleolithic diet. That sounds like a logical idea, I thought, and filed it away for future reference; there was no Internet then. In my time of need, I searched the Internet for Paleolithic diet and immediately found Don Wiss's www.Paleofood.com site. Also, a local diet.i.tian recommended a scientific paper by Eaton, Eaton, and Konner, and I was off. site. Also, a local diet.i.tian recommended a scientific paper by Eaton, Eaton, and Konner, and I was off.The first thing that I noticed on the diet was a feeling of a surge in my vitality. Within two weeks, my heel pain syndrome disappeared-a totally unexpected effect. My headaches soon reduced to once each two weeks and after eight months are down to once each 6 weeks or so and very mild at that-another unexpected effect.The weight fell off very quickly-15 pounds in the first month, and now 29 pounds altogether. If that wasn't enough, I've had an increase in my muscle bulk, despite having little chance to exercise. The end result was that my trousers were almost falling off me, but my shirts were getting tight across the shoulders. The effect on my fitness was immediate. The first time I went swimming on the diet, I clocked up 1,000 meters and was hardly puffing afterward. I can run around better than I can ever remember.My mental clarity has improved and is sharper than it has ever been before in my life. Everyone who knows me tells me how well I look. Interestingly, when I socialize, I'll often break the diet to be sociable. If I eat bread twice on the one weekend, I'll always get up on the Monday morning with sore heels again.Since then, I've studied the diet intensively. I am totally convinced [that] far more illnesses than [were] previously suspected are related to factors in the modern diet. In addition to the usual illnesses listed as dietary (hypertension, diabetes, hypercholesterolemia, cardiovascular disease, stroke), we can add many forms of arthritis, throat infection, peptic ulcer, acne, and many others.I plan to stay on the Paleolithic diet (as well as one can in this modern age) for the rest of my life. I think it's obvious from the above that I would be silly if I didn't!

A lean and healthy body is your birthright. The Paleo Diet is not a quick-fix solution. It is not a temporary, gimmicky diet. It's a way of eating that will gradually normalize your body weight to its ideal level and keep the pounds off permanently.

There's one very simple concept that you must understand when it comes to losing weight-the First Law of Thermodynamics, which states that energy is neither created nor destroyed. This means that the energy-calories-you put into your body must equal the energy you expend. Otherwise, you'll either gain or lose weight. If you eat more calories than you burn off, you'll gain weight. If you burn more than you take in, you'll lose weight.

Why Protein Helps Burn Calories When it comes to human metabolism, this basic law of physics is a bit more complicated: All calories are not created equal. All calories are not created equal. Protein is different from carbohydrates and fats. Protein is different from carbohydrates and fats.

How do you burn calories? Some you burn at a very low level all the time as part of your "resting metabolism"-for basic, unconscious functions such as beating of the heart, breathing, and digestion. You burn more calories when you move and still more when you exercise.

The common wisdom is that there are only two ways to burn more calories than you eat: Eat less or move around-exercise-more.

But there's another way to burn calories-a subtle process that can work wonders over weeks and months to create a substantial, long-term caloric deficit. Best of all, you don't even have to get out of bed to reap the benefits. This amazing phenomenon is called the "thermic effect," and the key to making it work is protein.

This is how it works: During the digestive process, your body breaks down food into its basic components-carbohydrates, fats, and proteins-and turns them into energy it can use. There's a trade-off: To get the energy from the food, the body must spend some of its own energy. There's a scientific name for this use of energy to digest and metabolize food-"dietary-induced thermogenesis" (DIT). Carbohydrates and fats generate about the same low DIT. Protein's DIT is huge in comparison-more than two and a half to three times greater. So, in order for the body to obtain energy from dietary protein, it must give up almost three times more energy than it needs for either fat or carbohydrates.