As I said in the last newsletter, if you want to know the dietary secrets of our Stone Age ancestors that kept them lean, healthy and strong, then you will be delighted to read "The Paleo Diet: Lose Weight and Get Healthy by Eating the Food You Were Designed to Eat." Author Dr. Loren Cordain, who is considered one of the world’s leading experts on Paleolithic (Stone Age) nutrition, explains in a simple, straightforward manner why today’s typical American diet of the wrong fats and too many starches, sugars and grains is contributing to so-called modern diseases like heart disease and cancer.

This book provides many valuable insights in how to eat in a way that prevents modern diseases, and here Dr. Cordain expands on some of those insights.

The following is from an e-interview we recently had with Dr. Loren Cordain:

What did you hope to achieve by writing 'The Paleo Diet'?

The theoretical basis for "The Paleo Diet" stems from the numerous scientific papers our research group has written on various aspects of ancestral human nutrition and health (all of these papers are available as free PDF downloads at my Web site: www.thepaleodiet.com). Because the general public infrequently reads the scientific literature, I felt that our message should be delivered to a much larger audience in an easy to read, practical and popular book format.

Secondly, I felt it important to provide the general public with the nuts and bolts of a premise that increasingly is being recognized by the scientific community as "the unified field theory" for human nutrition. Simply put, human nutritional requirements for optimal health are determined by our genes, and our genes are shaped by the environment of our ancestors through natural selection. Many modern staples and processed foods were not present throughout most of the more than 2 million years hominin species have been present on earth.

The nutritional qualities of modern processed foods and foods introduced during the Neolithic period are discordant with our ancient and conservative genome. This genetic discordance ultimately manifests itself as various chronic illnesses, which have been dubbed "diseases of civilization." By severely reducing or eliminating these foods and replacing them with a more healthful cuisine, possessing nutrient qualities more in line with the foods our ancestors consumed, it is possible to improve health and reduce the risk of chronic disease.

Finally, I wanted to show that by replacing Neolithic foods such as whole grains and dairy products with fresh fruits, veggies, lean meats and seafood, it is possible to produce a perfectly healthful and nutritious diet. In fact, this type of diet is more healthful and nutrient dense than the USDA Food Pyramid diet, the Mediterranean Diet, or a low-fat, vegetarian diet. As I have pointed out in our scientific papers, this type of diet positively influences multiple dietary parameters (n6/n3 fatty acid balance, glycemic load, acid/base balance, trace nutrient density, Na/K balance, fiber, and macronutrient balance), which underlie virtually all the diseases of civilization.

Who would benefit from reading 'The Paleo Diet'?

Virtually anyone who is interested in improving their health or the health of others would benefit from the information contained in "The Paleo Diet."

What would you say to people who disagree with your assertion that saturated fat causes heart disease?

First off, let's get the record straight. I have never said that saturated fat is the sole dietary cause of "heart disease." Coronary heart disease (CHD) consists of myocardial infarctions (heart attacks) and angina pectoris and accounts for 54 percent of the deaths from a larger category of heart and blood vessel illnesses called cardiovascular disease (CVD), which accounts for 40.6 percent of all deaths in the United States. CVD not only includes CHD, but also stroke, congestive heart failure, hypertension, rheumatic heart disease, congenital cardiovascular defects, artery diseases and others.

The physiological mechanism underlying CHD is atherosclerosis, a complex process involving interactions among environmental factors (both nutritional and non-nutritional) and the genome. Environmental factors such as exercise, smoking and inflammation clearly influence the development and progression of atherosclerosis. Numerous nutritional factors can serve to either: 1) promote or 2) inhibit atherosclerosis via modulation of one or more of the steps involved in the atherosclerotic process.

Dietary saturated fats are nutritional elements that may promote atherosclerosis. As consumption of certain saturated fatty acids (12:0, 14:0, 16:0, but not 18:0) increases, the number of hepatic (liver) and peripheral low-density lipoprotein (LDL) receptors decreases, which in turn causes serum concentrations of LDL cholesterol to rise (a process called down regulation).

Down regulation occurs because internalization of 12:0, 14:0 and 16:0 within cells reduces the expression of genes that code for the LDL receptor protein. At low blood LDL cholesterol concentrations (20-50 mg/dl), LDL cholesterol molecules move freely in and out of the arterial intima (the portion of the artery where atherosclerosis arises). When blood levels of LDL cholesterol molecules rise, LDL molecules tend to become "stuck" in the intima where they undergo oxidation and glycation to become "modified LDL."

Modified LDL stimulates arterial endothelial cells to display adhesion molecules, which latch onto circulating monocytes and T cells. The endothelial cells then secrete chemokines, which bring the monocytes and T cells into the intima where they mature into macrophages. T-cells release cytokines causing inflammation and cell division within the artery. The macrophages are different from all other cells in the body in that they display a scavenger receptor that is not down regulated by LDL cholesterol molecules. The macrophages "feast" upon modified LDL cholesterol in the intima and become filled with these fatty droplets and become foam cells.

Cytokines cause smooth muscle cells to grow over the lipid core of multiple foam cells forming a tough fibrous cap, which becomes the characteristic plaque that defines atherosclerosis. Finally, inflammatory cytokines secreted by foam cells weaken the fibrous cap by digesting the collagen matrix. If the weakened cap ruptures, a substance secreted by the foam cells called "tissue factor" interacts with clot-promoting elements in the blood causing a thrombus (clot) to form. If the clot is large enough to halt blood flow, it causes a myocardial infarction (heart attack).

Dietary saturated fats do not always elevate blood LDL concentrations. When consumed under hypocaloric (reduced energy) conditions they may improve most blood lipid parameters including total and LDL cholesterol, HDL cholesterol and total triacylglycerol (TG).

This phenomenon typically explains why Atkins-like diets (such as recently reported this spring in the New England Journal of Medicine) may be as, or more, effective than hypocaloric, low-fat, high-carbohydrate diets. However, under isocaloric (normal energy) conditions, studies of healthy normal subjects show increased consumption of saturated fats significantly raises blood LDL concentrations.

A further confounding factor in this scenario is the presence of a specific type of LDL cholesterol molecule in the blood called "small dense LDL." The rate of influx of LDL into the intima is not only related to the blood concentration of LDL cholesterol, but also to the size of the LDL molecule. Small dense LDL have a greater flux into the intima than normal LDL and they are more likely to get "stuck" in the intima because of increased binding to proteoglycans.

The primary metabolic source of small dense LDL is very low-density lipoprotein molecules (VLDL) whose blood concentration is greatly influenced by dietary carbohydrate, particularly high-glycemic-load carbohydrates. Hence foods with high glycemic loads such as those made with refined sugars and grains may also operate synergistically with high dietary saturated fats to promote atherosclerosis. Additionally, high-glycemic-load carbohydrates are positively correlated with plasma concentrations of C-reactive protein, an important marker for systemic inflammation, a key element of the atherosclerotic process, as I previously noted.

The gold standard procedure for demonstrating cause and effect between diet and disease is called a dietary intervention. Subjects are either fed or not fed a certain food or nutrient and then either presence or absence of a disease or disease symptom is monitored over time. With CHD, the results of dietary interventions in which saturated fats have been lowered, frequently have been unable to demonstrate a reduced mortality from CHD.

The problem with the majority of these studies is that they were conducted prior to the knowledge that high-glycemic-load carbohydrates were an important promoting factor in CHD etiology. Further, most of these studies did not control for inhibitory dietary factors such as omega-3 fatty acids, fiber, phytochemicals, antioxidants, etc. Hence, the interpretation of whether or not dietary saturated fats cause CHD in these interventions is confounded by a number of crucial variables. In animal studies, including primates, these confounding dietary factors can be completely controlled and atherosclerosis is routinely induced by solely feeding high amounts of saturated fat.

How important is it to eat naturally raised meat as opposed to the commercial meat found in most supermarkets?

Grass-, pasture-fed and free-ranging animals yield meat that is lower in total fat, saturated fat and higher in the beneficial omega-3 fatty acids and is preferable to the flesh of grain-fed animals. However, by eating plenty of fish and seafood along with healthful oils (fish oil, flaxseed oil, canola oil, olive oil and others) supermarket lean meats certainly can be included in the diet.

What can people expect from following your advice about nutrition?

Most people experience an increase in energy within a day or two of beginning the diet. They don’t feel the mid-morning or mid-afternoon "blahs" or energy slumps. Protein is a great satiator and most people find themselves not being hungry during the day and eating less at all meals. Because protein has twice the thermic effect of either fat or carbohydrate, it revs up your metabolism and helps you lose weight along with its ability to reduce the appetite.

Moreover, this diet is really not a diet at all, but rather a lifetime plan of eating that promotes good health. Most of the chronic diseases of civilization that afflict the majority of Americans can be substantially improved or eliminated by eating the types of foods native to the original human diet.

If you could give your readers one bit of advice from 'The Paleo Diet,' what would it be?

Eat unlimited consumption of lean meats, seafood, fresh fruits and veggies at the expense of processed foods, cereal grains and dairy products.

When did you first become interested in nutrition?

I suppose it probably began in my childhood from my mother encouraging me to eat my fruits and veggies and from my father who gave me books about Stone Age people and how they lived off the land from wild plants and animals. In the late ‘60s and early ‘70s I was involved in intercollegiate athletics and became more interested in diets that could improve my performance. I read a wide variety of popular and now classic health books on vegetarian dieting such as Frances Moore Lappe’s book, "Diet for a Small Planet," and books by Norman Walker, Paavo Airola and others. Later as a graduate student at the University of Nevada-Reno, and as a doctoral student at the University of Utah, I became involved in research involving body fat measurements.

As a young professor at Colorado State University, along with my graduate students, I initiated a wide variety of research projects involving diet and athletic performance. I was introduced to the Paleo Diet concept in about 1987 when I read Dr. Boyd Eaton’s seminal New England Journal of Medicine paper, "Paleolithic Nutrition." It made perfect sense to me at the time, and I voraciously read everything I could about the concept and related topics. A number of years later, I gave Dr. Eaton a call and invited him to speak at Colorado State University--we hit it off after our meeting and began writing together, and the rest can probably be found in the scientific literature.

Do you have plans to write another book?

Yes, as we speak I am currently writing a book that will be tentatively called, "The Paleo Diet for Athletes." My co-author for this project is Joe Friel, a longtime friend and author of the best selling, "Triathletes Training Bible," and an Olympic Triathlete coach. Rodale Press will be publishing our book and we expect it to be released early in 2005.

Cave Men Diets Offer Insights to Today's Health Problems

First, Catch Your Cow

Caveman Cuisine

The Paleolithic Diet and Its Modern Implications