The Paleolithic Diet, Part II: What is the Evidence?

In The Paleolithic Diet, Part I: A New Look at Our Oldest Diet, I described the background and nature of the modern Paleolithic diet, popularly known as the Paleo diet and medically known as the ancestral human diet. The Paleo diet eliminates grains and dairy and consists of lean meats, fish, vegetables, fruits, nuts, and berries.

But, is there evidence for this diet? On one level, evidence comes from general medical science as it struggles to answer, why, despite the most advanced medical treatments available, health in the U.S. seems to be declining. A consensus is slowly developing that we are straying ever further from our natural diet and have made rash decisions with minimal or flawed evidence. Journalist Marni Jameson, in the article A reversal on carbs published in Los Angeles Times December 20, 2010, quotes Dr. Frank Hu, Professor of Nutrition and Epidemiology at the Harvard School of Public Health:

The country's big low-fat message backfired. The overemphasis on reducing fat caused the consumption of carbohydrates and sugar in our diets to soar. That shift may be linked to the biggest health problems in America today.

And, quoting Dr. Walter Willet, Chairman of the Department of Nutrition, Harvard School of Public Health:

Fat is not the problem. If Americans could eliminate sugary beverages, potatoes, white bread, pasta, white rice and sugary snacks, we would wipe out almost all the problems we have with weight and diabetes and other metabolic diseases.

As part of this reassessment of contemporary dietary advice, evidence favoring the ancestral human diet is slowly building. Many persons have adopted this new (yet, very old) nutritional approach out of frustration. Their passionate, self-reported cases, describe how they have overcome obesity, anorexia, diabetes, and other forms of malnutrition. (Some of these cases can be found through PaleoTerran.com. Select Success Stories in the right hand menu.)

Research Studies

One of the earliest research studies on the Paleolithic diet, performed by Kevin O’Dea, was published in Diabetes in June 1984. Ten Australian Aborigines, who as young adults had moved from the Outback to rural areas, and then became overweight and developed type 2 diabetes, were asked to consider returning to the Outback and eating like they had during their childhood.  They agreed and, as described by Dr. Loren Cordain in The Paleo Answer, for 7 weeks lived on “kangaroos, birds, crocodiles, turtles, shellfish, yams, figs, yabbies (freshwater crayfish), freshwater bream, and bush honey.” The results: “the average weight loss in the group was 16.5 pounds; blood cholesterol dropped by 12%, and triglycerides reduced by a whopping 72%. Insulin and glucose metabolism became normal, and their diabetes effectively disappeared.”

In a study published in Cardiovascular Diabetology in July 2009, Jönsson and colleagues investigated whether 13 persons with type 2 diabetes would do better on a diabetes diet or on the Paleolithic diet. Even though the study was small, it was designed in a powerful manner called a randomized cross-over study. The subjects were placed on a Paleolithic diet and a diabetes diet “during two consecutive 3-month periods.” The results were clear: study participants became healthier on the Paleolithic diet. Their weight and Body Mass Index (BMI) were lower and their waist circumference was smaller on the Paleo diet. In addition, they had lower diastolic blood pressures, improved diabetic blood test (HbA1c, blood glucose) and lower triglycerides, along with higher levels HDL cholesterol (the good cholesterol).

In August 2009, Dr. Frasetto and colleagues published a study in the European Journal of Clinical Nutrition on the effects of the Paleolithic diet in 9 inactive volunteers that were not obese. The Paleolithic diet was matched to the same number of calories they had previously consumed. After just ten days on the Paleolithic diet, all had lower blood pressure, improved oral glucose tolerance test, and  “large significant reductions in total cholesterol, low-density lipoproteins (LDL) and triglycerides.” Their health on the Paleo diet markedly improved even though they consumed the same number of calories as they had previously. In addition, as Dr. Cordain noted, “What is most amazing about this experiment is how rapidly so many markers of health improved – and that they occurred in every single patient.”

How does the Paleolithic diet compare to the Mediterranean diet? In a separate study in the November 2010 issue of Nutrition & Metabolism, Jönsson and colleagues compared the satisfaction provided by both diets. (In medical terms, we are “satiated” when the meal satisfies our appetite.) Fourteen persons ate a Paleolithic diet of “lean meat, fish, fruit, vegetables, root vegetables, eggs, and nuts” and 15 were on Mediterranean diet consisting of “whole grains, low-fat dairy products, vegetables, fruit, fish, and oils and margarines.” The results: calorie for calorie, the Paleolithic diet was more satiating. It takes more calories with the Mediterranean diet to satisfy hunger, another win for the Paleolithic diet.

Summary

In summary, the modern Paleolithic diet is an approximation of the ancestral human diet consumed before the advent of agriculture and animal husbandry. It has been our diet for over 90% of our existence and is part of our genetic heritage. The Paleolithic diet is non-inflammatory, an important factor in disease prevention. While the evidence is just developing, the Paleolithic diet is proving to be an important means to reclaiming our original health. The story is just beginning.  

(Article initially published in Living Well magazine)

Read Part 1 here.

The Paleolithic Diet, Part I: A New Look at Our Oldest Diet

According to Duke University and the CDC, 42% of Americans will be obese by 2030. Despite advances in health care, the number of people with diabetes, heart disease, stroke, Alzheimer’s disease, and other modern diseases continues to increase. What is going wrong?

Some attribute the increase in obesity, an underlying factor in many of the modern diseases, to a lack of will power, a puzzling argument that fails to explain the increasing body mass over the past three decades. Others blame easy availability of food and lack of exercise: we take in too many calories and don’t burn enough. The simplistic solution proposed: eat less and exercise more. While our sedentary lifestyle contributes to obesity, the real culprit is low-quality fuel. We chose, and are surrounded by, low quality foods. Physical anthropologist Gary J. Sawyer puts it simply:

“We do not know how to eat properly. We feed ourselves, but we fail to give ourselves proper nutrition.”

A new look at our oldest diet

Fortunately, we are beginning to understand the underlying factors triggering modern diseases, among them, chronic inflammation. According to the December 2010 Science journal:

“Over the past decade it has become widely accepted that inflammation is a driving force behind chronic diseases that will kill nearly all of us. Cancer. Diabetes and obesity. Alzheimer’s disease. Artherosceloris. Here, inflammation wears a grim mask, shedding its redeeming features making sick people sicker.”

The typical Western diet is inflammatory; the diet of our Paleolithic ancestors was non-inflammatory. While the agricultural revolution around 10,000 years ago, and animal husbandry a few thousand years later, led to modern civilization, they also began to undermine our health. We became shorter and developed bone mineral disorders and nutritional deficiencies. We became less robust and developed smaller jaws. As summarized in a recent study: “Early Farmers Were Sicker and Shorter Than Their Forager Ancestors.”

What is the Paleo diet?

Interest in the ancestral human diet is growing. For over 180,000 years before agriculture, our diet was simple, yet more varied than the modern diet. Loren Cordain, professor of Health & Exercise Science at Colorado State University and one of the world’s leading experts on Paleolithic nutrition, has analyzed the diets of over 200 hunter-gatherer societies and described the ancestral diet in two recent books: The Paleo Diet and The Paleo Answer.

Our pre-agricultural ancestors “ate no dairy,” which triggers the immune system and causes a similar rise in insulin as white bread. Except in conditions of starvation they did not eat grains. Unlike ruminants, humans can’t ferment grains and only extract significant energy from grains when processed.

The role of grains as a cause of inflammation is coming under greater scrutiny. While gluten allergy and sensitivity are recognized conditions, only recently are we recognizing that gluten can affect the nervous system and in some people cause gluten ataxia, gluten spinal inflammation, and gluten neuropathy.

The non-inflammatory Paleolithic diet consists of varying amounts of lean meats, fish, seafood, vegetables, fruits, tubers, nuts and berries and significantly reduces, or eliminates, grains and dairy.

Vegetables are “rich in a long list of nutrients,” and, per calorie, non-starchy vegetables have seven times the fiber of whole grain cereals. The typical modern diet contains “a measly 8 grams” of fiber “compared to 47 grams on the Paleo Diet.”

Fruits are “almost as nutrient dense as vegetables.” Dr. Cordain believes you “have to consume huge amounts to get much fructose.”

Fish and shellfish are rich in fatty acids crucial to nervous system function. It is probably not a coincidence the first signs of human consciousness 70,000 years ago were produced by ancestors living next to the sea and thriving on a diet rich in fish and seafood.

Meats have twice the “thermic effect” of fat or carbohydrate (they increase metabolic rate) and have the highest “satiating value” (satisfy hunger). Meats increase good HDL cholesterol, are the best source of iron, B12, and zinc, and are rich in the building blocks of enzymes and brain neurotransmitters.

The right fats are essential to human health. Unfortunately, the typical diet tilts heavily to saturated fats. Cordain’s laboratory found “that despite their high meat content, modern-day Paleo diets actually contain lower quantities of saturated fats than are found in the typical U.S. diet. Two-thirds of all of the saturated fats that Americans consume come from processed foods and dairy products.”

(Article initially published in Living Well magazine)

Part 2 will review the developing medical evidence favoring the Paleolithic diet.

Milk and exercise-induced asthma

iStockphotoIn his most recent book, The Paleo Answer, Dr. Loren Cordain, takes a deeper dive into the mechanisms through which the typical Western diet contributes to illness. On the relationship between milk and exercise-induced asthma, Dr. Cordain writes:

If the gut becomes leaky, which it invariably does on a typical Western diet, beta casomorphin-7 in milk can enter our blood stream and travel to our chests, where it stimulates production from MUC5AC glands located in our lungs and respiratory tracts. A final piece of this puzzle is that beta-casamorphin-7 is much more likely to trigger mucous production if the lungs and the respiratory tract are inflamed by asthma. Many people’s exercise-induced asthma symptoms disappear on the Paleo Diet.

He then presents a case reported by a personal trainer:

I am a trainer, and I work with very overweight woman, Jenny, who recently started my boot camp. She weighs 360 pounds at present. Until recently, she also suffered from exercise-induced asthma. For the first week of boot camp, she could ot get through a class without her inhaler. Although I admired her dedication, it was painful and a bit scary to watch.

Then I put her on the Paleo Diet. This week, after doing this for a little less than two weeks, she no longer needs her inhaler. Miraculous!

Jenny’s also doing great on the diet – she’s not hungry at all, so I know the weight will be coming off soon as well. 

SUNDAY PALEO / April 15, 2011

Review: In Search of the Perfect Human Diet

On Memorial day 1978, I dropped dead.

Thus starts the new documentary, In Search of the Perfect Human Diet, by producer CJ Hunt. At 24 years of age, Hunt had suffered a heart attack while running track. On discharge following a 10-day hospitalization, he was given the following advice: “Don’t walk up stairs. Don’t go anywhere without someone that knows CPR. You have over a 50% chance of dying in the next two years.”

Deeply shaken, CJ began a “personal quest for optimal health.” Over the subsequent years, in pursuit of the best possible health, he “experimented with a wide variety of eating methods, cleansing fasts, and dietary philosophies.” A cardiac defibrillator, implanted at the age of 46 to restart his heart should it stop working, became a constant reminder of his mortality and triggered “a 10 years journey to find the perfect human diet.”

At the beginning of his quest, Hunt recalled his parent’s advice (advice we could all use at various times in life):

1. “Do your homework.”
2. “Be willing to look past conventional wisdom.”
3. “Don’t be afraid to go back and start at the beginning and see where it leads you.”

With bags packed, Hunt set out to interview nutritional experts throughout the world, many who are “flying below the radar of conventional dietary thinking.”

In an interview of Professor Karen Oday, Hunt learns of a small, yet classic, study with 10 Australian aborigines who, as young adults, had moved into towns and eventually developed type 2 diabetes. Each was asked each if they would consider living in the bush for 7 weeks and forage for their own food. All agreed. After just 7 weeks, their insulin and glucose metabolism returned to normal! Furthermore, an assessment of their activity level, surprisingly, was found to have been somewhat less in the bush. (This finding supports the concept that hunter-gatherers had more leisure time than people in modern cultures.)

Jay Wortman, MD discusses the nutritional insights gained while helping the First Nations people of Canada reclaim their health by returning to their traditional diet. Michael R. Eades, MD emphasizes the importance of protein in the human diet.

Science journalist Garry Taubes, author of Why We Get Fat, provides a historical perspective on missteps that have led the current increase in obesity and chronic diseases. He explains how the demonization of dietary fats led to a marked increased in the consumption of refined carbohydrates, an underlying factor in many modern preventable diseases. Andrew Weil, MD, founder and director of the Arizona Center for Integrative Medicine, reinforces this point:

Fat does not make us fat. What is driving the obesity epidemic in this country is the very high glycemic load carbohydrate foods which have been technically manipulated.

Adele Hite, MPH, MAT, Executive Director of the Healthy Nation Coalition, discusses the origin of the USDA food pyramid:

From the start, our dietary recommendations have been based as much on politics as on science.

Hunt then travels to Colorado State University to interview Professor Loren Cordain, “America’s leading expert on evolutionary nutrition.” Cordain relates how he developed an interest in Paleolithic nutrition after a reading the “classic article” by Dr. S. Boyd Eaton, published in the New England Journal of Medicine in 1985.

Dr. Cordain then takes Hunt on the CSU football field to provide “a sense of scale” to human dietary evolution. Beginning on one end of the field (viewed as 2 million years ago), both slowly walk down the field as Cordain points out the time periods of various dietary changes and finally reaches the development of processed foods beginning around 1900 to the present.  This final period represents a miniscule portion of the entire evolutionary timeframe: “the last 1/5 of the last inch” of the hundred-yard field. Frankly, an astoundingly small period of time; so brief, it exposes the typical modern diet as an experiment, one whose outcome we are now beginning to comprehend.

This is a good place to pause the video. Get up and walk around. Get a Paleo snack and come back soon for the rest of the story.

Paleolithic Nutrition: Diet and Modern Disease

By John Michael & Dr. John

In the United States and most Western countries, diet-related chronic diseases represent the single largest cause of morbidity and mortality. These diseases are epidemic in contemporary Westernized populations and typically afflict 50–65% of the adult population, yet they are rare or nonexistent in hunter-gatherers and other less Westernized people. Although both scientists and lay people alike may frequently identify a single dietary element as the cause of chronic disease (e.g., saturated fat causes heart disease and salt causes high blood pressure), evidence gleaned over the past 3 decades now indicates that virtually all so-called diseases of civilization have multifactorial dietary elements that underlie their etiology, along with other environmental agents and genetic susceptibility.

Origins and evolution of the Western diet: health implications for the 21st century
Dr. Loren Cordain

From the Neolithic, through the age of discovery and the industrial revolution, up to the present day, human invention and innovation have introduced numerous foods into our daily diets, including vegetable oils, salts and refined sugars, and the multifarious forms that processed grains can take. Along with the introduction of these foods, people in Western Civilization have begun to suffer from many diseases that have a low prevalence among hunter-gatherer and even traditionally agrarian societies. According to Dr. Loren Cordain in his paper, Origins and Evolution of the Western Diet: Health Implications for the 21st Century, “The evolutionary collision of our ancient genome with the nutritional qualities of recently introduced foods may underlie many of the chronic diseases of Western civilization. 

Cordain bases this statement upon the idea of evolutionary discordance, which occurs when an environment changes in such a way that its inhabitants are no longer properly adapted for survival within it. Because the majority of human evolutionary history was spent within a hunter-gatherer context in which fruits, vegetables, meats, nuts and seeds, along with some tubers, were the dominant food sources, our bodies are adapted to consume this diet. The modern Western diet contains refined sugars, processed grains, and vegetable oils, among other novel foods, that were not available to our ancestors, and so our bodies perform sub-optimally when it comes to their digestion. And not only are our bodies poorly adapted for the consumption of these modern foods; in many cases, their consumption is causing us harm.

This damage takes the form of illnesses like type 2 diabetes, hypertension, dementia, cancer, osteoporosis, and autoimmune disease, to name a but few. Scientists working in Burkina Faso, Africa, believe that overall health may be tied to the bacteria people have living in their gut, basing this belief on their observation that traditionally agrarian Africans have healthier gut bacteria due to their diets and lifestyle, which implies that our own guts, which are more susceptible to allergies, autoimmune disorders, and inflammatory bowel disease than those of the Africans in this study, are in such a sorry state because of what we eat and how we live. After stating that our Western diet is “killing us,” the Coronary Health Improvement Project (CHIP) presents this somber collection of statistics.

Because of thickened, narrowed and hardened arteries, 4,000 Americans succumb to heart disease and have heart attacks every day.  Every third adult has high blood pressure, and thousands are crippled from strokes. Because of disordered metabolisms from unbalanced lifestyles, obesity is epidemic, and a new diabetic is diagnosed every 50 seconds.

And, according to Cordain, “Cancer is the second leading cause of death (25% of all deaths) in the United States, and an estimated one-third of all cancer deaths are due to nutritional factors, including obesity.”

To understand the gravity of this situation, one need only look to the executive summary of the WHO’s Global Status Report on Non-Communicable Diseases (NCD) 2010, in which unhealthy diet was included among the four risk factors that contribute to the majority of NCD deaths worldwide. The UN report goes on to state, “People in developing countries are increasingly eating foods with higher levels of total energy and are being targeted by marketing for tobacco, alcohol and junk food, while availability of these products increases,” which is to say that this dietary problem is spreading globally. The epidemic of diet-based poor health has an economic impact as well, which the report addresses with this sobering statement, “Each year, an estimated 100 million people are pushed into poverty because they have to pay directly for health services.” The report concludes by suggesting that governments enact legislation and propaganda campaigns to inform and protect their citizens from the dangers of an unhealthy diet, and that they do so now. However, the slow swell of education by knowledgeable health care providers and online primal & Paleo educators should result in a more powerful and lasting dynamic for change.  

Becoming Paleo, Part 1: The Yale Food Addiction Scale

Posted by John Michael

Society’s strong motivation to lose weight combined with the tremendous amount of energy and resources spent on the “obesity epidemic” suggests that the problem of obesity is not driven by a lack of motivation or effort.

Preliminary Validation of the Yale Food Addiction Scale

I’ve known about the Paleo Diet for several years, ever since my dad started altering his eating habits to match those set out in Dr. Loren Cordain’s book The Paleo Diet: Lose Weight and Get Healthy by Eating the Food You Were Designed to Eat. “The fact is,” Dr. Cordain writes on his website, “that virtually our entire physiologies operate exquisitely when they are functioning in the native human ecological niche in which they evolved – employing both the diet and exercise level of a hunter-gatherer.” I’d always had problems with diet and exercise (like many Americans, according to the statistics), so when my father told me about the Paleo Diet, I was interested, but acquiring it didn’t seem feasible, because, while I recognized that this diet was probably my best option, I couldn’t control my eating habits, which were driven by cravings that appeared out of my control, and the Paleo Diet is all about restricting what we eat to the foods that our hunter-gatherer ancestors enjoyed. The diet remained in my head, a seeming impossibility until recently, when Yale University published the Yale Food Addiction Scale, and I decided to take control of my eating habits. 

The Yale Food Addiction Scale is a survey designed to detect and measure the severity of food addiction. While food addiction’s not fully recognized by the medical establishment as a disorder, several studies have been conducted to explore the possibility of its existence. Although some of these studies seem strange, like the one which found that rats preferred high doses of sugar to comparable doses of cocaine, or the one which studied the fierce sweet tooth that former alcoholics can develop, others are serious attempts to define what food addiction is and to create tools that measure it. (Interestingly, all of these studies suggest that food addiction is caused by the exorbitant excitation of reward circuits that evolved in our brains during the times of our hunter-gatherer ancestors. This leads me to speculate that perhaps food addiction is due to an excessive stimulation of these reward circuits, which evolved in the absence of “high fat and high sugar foods,” and which were perhaps never meant to be as stimulated as they are today.)

After reading about the release of the Yale Food Addiction Scale, I decided to take it myself, because I had recognized my own eating problem in the articles that I had read about it. The survey, composed of twenty-seven items, is based on the American Psychiatric Association’s substance dependence criteria, as well as other scales “used to assess behavioral addictions, such as gambling, exercise, and sex.” As I took this survey, my eating problem began to take shape in my mind. It was most revealed by the items that I scored highly on. The first sixteen items are statements, like, “I find that when I start eating certain foods, I end up eating more than planned,” that the participant scores from 0 to 4, with 0 being “never,” 1 being “once a month,” 2 “2-4 times a month,” 3 “2-3 times a week,” and 4 “4 or more times daily.” Among the statements that I marked 4 on were, “I find myself continuing to consume certain foods even though I am no longer hungry,” “I have consumed certain foods to prevent feelings of anxiety, agitation, or other physical symptoms that were developing,” and, “My behavior with respect to food and eating causes significant distress.” The second to last item asks participants to check foods that they “have problems with.” Which foods did I mark? Ice cream, hamburgers, cheeseburgers, soda pop, chocolate, doughnuts, and cookies.

Like I’ve told students in the classroom, the first step in solving a problem is recognizing that you have one. I had known for years that I had a problem with eating, and now, with the Yale Food Addiction Scale, I had begun to take the second step in problem-solving: observing the problem that you have, so that you can figure out a way to solve it. 

Stay tuned for Becoming Paleo, Part 2: The Anxiety Barrier.

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Becoming Paleo, Part 2: The Anxiety Barrier 
Becoming Paleo, Part 3: Breaking the Anxiety Barrier 
Becoming Paleo, Part 4: The Projections of Anxiety 

John Michael is a traveling writer and a teacher with a deep interest in humankind’s connection to the natural world. Learn more.