Interview: Dr. Loren Cordain discusses the Paleo Diet

Dr. Cordain received his Ph.D. in Health from the University of Utah in 1981, and has been a Professor in the Department of Health and Exercise Science at Colorado State University since 1982.  He is married and has three sons.

Featured on Dateline NBC, the front page of the Wall Street Journal, and the New York Times, Loren Cordain is widely acknowledged as one of the world’s leading experts on the natural human diet of our Stone Age ancestors.

He is the author of more than 100 peer-reviewed scientific articles and abstracts.  His research into the health benefits of Stone Age Diets for contemporary people has appeared in the world’s top scientific journals including the American Journal of Clinical Nutrition, the British Journal of Nutrition, and the European Journal of Clinical Nutrition among others.

Dr. Cordain’s popular book, The Paleo Diet, has been widely acclaimed in both the scientific and lay communities.  His next book, The Paleo Diet for Athletes, was published in October 2005, and discusses how the Paleo Diet can be modified for the high-performance endurance athlete, and lead to improved health and performance. One of his more recent books, The Dietary Cure for Acne, is available in paperback and as an instant download ebook.

He is the recent recipient of the Scholarly Excellence award at Colorado State University for his contributions into understanding optimal human nutrition

Recently, Michael had the pleasure of chatting with Dr. Cordain about all things Paleo.

Dr Cordain welcome. Over the past year the Paleo diet seems to have gained popularity across the world. In particular in my home country of Australia, I have noticed the mainstream media has recently started to cover the diet. Then when you look at how well it has been adopted by the CrossFit community it really seems to have taken off. Does this surprise you?

I’ve spoken in Australia three times, and have always noticed a great interest in the Paleo Diet concept that has accelerated upon each subsequent visit.  My perception in Australia is similar to the situation in the U.S.  If you visit Google Trends and type in Paleo Diet (http://www.google.com/trends/?q=paleo+diet), you can see the enormous increase in this concept that has occurred worldwide in the past three years. See the graph below:

One of the driving forces behind the increased interest in Paleo diets is the international CrossFit movement, which has adopted this lifelong nutritional plan as their de facto diet.

Reebok has recently become associated with the CrossFit movement and helps to sponsor the CrossFit games and give it international publicity. I am only surprised by how long it has taken for Paleo Diets to finally take off and hit the mainstream, as my first book was released in December 2001.

When I travel back to the U.S. I notice that the Zone diet is also popular within the CrossFit community. However I recently noticed Paleo seems to have gained a little more traction, do you think there is a reason for this?

I speak to the CrossFit community from coast to coast in the U.S., and my perception is similar to yours in that the Zone diet doesn’t have the support it use to have with CrossFitters.

I attribute this increased support for Paleo Diets to a number of factors. First, no complex formulas regarding macronutrient percentages exist with Paleo – eat as much real food (fresh meats, seafood, fruits and veggies) as your appetite dictates.

Secondly, this simple formula works. People lose body fat, gain muscle, strength and endurance while virtually all indices of health improve. Finally, the Paleo Diet concept has gained traction because numerous CrossFit websites worldwide have gotten the word out demonstrating the Paleo Diet’s effectiveness, including my former graduate student, Robb Wolf’s website.

So how did you become involved with the Paleo diet?

As an undergraduate student from 1968 to 1972 I was involved in intercollegiate athletics and was interested in fitness and how diet could improve my performance just as CrossFitters are doing now. They are asking the same questions my generation asked.

In the late 60s, early 70s, we all thought a vegan/vegetarian diet was the healthiest diet and the best nutritional strategy to improve performance. Nevertheless, the science underlying this notion was weak or non-existent. Then the carbohydrate loading theory materialized with the idea that eating lots of carbs would promote endurance performance. Few people questioned this concept, myself included.

As I experimented with vegetarian dieting in the 70s and 80s, I invariably got injured more often, had more upper respiratory illnesses —  both of which reduced the quality and quantity of my training.

After earning my Ph.D. in Health Sciences at the University of Utah in 1981, I was hired as a faculty member at Colorado State University. Five years later, I came across a scientific article (Paleolithic Nutrition – A Consideration of Its Nature and Current Implications, by Boyd Eaton, M.D.) that appeared in the New England Journal of Medicine. After reading this paper, I thought it was the best paper on the ultimate basis for optimal human nutrition that I had ever read.

Upon reading Dr. Eaton’ seminal article in 1987, I began to collect and organize the 80 or so references cited in this paper. As I got more involved in Boyd’s seminal concept, I started to see patterns emerge: Stone Age people didn’t eat grains; they didn’t drink milk or eat dairy products. The meat they ate came entirely from wild animals whose fatty acid makeup differed considerably from the flesh of feed lot produced animals.

As I began to organize these concepts, I separated each topic into file folders with sub topics — for instance under the heading of cereal grains, I created sub folders containing articles that discussed the adverse health effects of grains from their high glycemic index to their high phytate content.

As I started to see these patterns emerge, I obtained and read the references cited in the previous papers. These new patterns caused me to create entirely new file folders with endless subfolders of scientific papers. Finally a much larger concept came to me, and this idea formed the basis for the Paleo Diet concept, which is now sweeping the world.

So what types of health related issues and possible diseases do you argue maintaining a Paleo diet can prevent?

There’s a famous internationally known physician in Australia, Dr. Ben Bowser, who’s been involved with Paleo for a long time. He and I sat down many years ago, before any of this hit the world scene, and we concluded that there were very few chronic diseases that did not improve or completely remit when people adhering to The Paleo Diet.

Slowly but surely this information is now being confirmed in the scientific literature as randomized controlled trials test the therapeutic effect of contemporary diets based upon Palaeolithic food groups.

When I initially became involved in evolutionary nutrition, I knew that common diseases of civilization like hypertension, high cholesterol and cardiovascular diseases could be reduced or totally prevented by maintaining a contemporary Paleo diet.

In the future I expect to see scientific experiments testing the efficacy of Paleo diets in autoimmune disease patients. Our research group currently has obtained data from approximately 100 autoimmune disease patients who have adopted the Paleo Diet for its therapeutic effects upon the progression of their diseases.  We are in the process of writing up this large case study.

In regards to grains and dairy: do you have an opinion about one possibly being worse than the other? For instance, if a person was to exclude only grains or exclude only dairy from their diet, would they still experience the benefits of a Paleo diet?

I think those questions will be answered by the next generation, the people who are in their 20s, 30s and 40s. They didn’t learn the dogma that grains and dairy were required for all human beings.

There’s no nutritional grain requirement for humanity or any other primate that can’t be met by other animal and plant foods. Similarly, humans have no nutritional requirement for the milk of another mammalian species throughout our lives.

As a species, we can get along fine without either of those food groups. The novel concept promulgated by the USDA and other governmental agencies and public institutions is that these food groups are required by all humans for optimal nutrition.

In fact, as we have pointed out in the scientific literature a number of times, grains and dairy are nutritional lightweights when it comes to the 13 micronutrients (vitamins and minerals) most lacking in the U.S. diet. Fresh vegetables, seafood, lean meat and fresh fruit are all more nutrient dense than are whole grains cereals and whole milk.

I know people who are doing 80% Paleo, do you think that is a bad idea?

When my wife convinced me to write my first book (The Paleo Diet) she said, “You need to write a book that reaches the masses, that reaches the average person.”

Accordingly, most people would be apprehensive to adopt a diet that would never allow them to eat their favourite processed foods, be it an occasional glass of wine, a slice of cheese or a chocolate. So when I was writing the first book, I knew that I had to make The Paleo Diet practical and workable for the average person. This practicality concept became the 85/15 rule in my first book.

The theory is what you eat 85 percent of the time will impact you more health wise than what you eat 15 percent of the time. Most people will experience significant health improvements if they are at least 85 % compliant with the Paleo Diet.

This notion of practicality was the guiding light with the Paleo Diet. We had to make it behaviourally acceptable so you could have al slice of pizza, or a beer, or eat a donut occasionally. This concept has never been tested experimentally, but many people anecdotally report health improvements and weight losses when they are 85 percent compliant.

CrossFitters worldwide report that their physical performances improve while eating Paleo. People who have serious health problems, or who are severely overweight should try to be nearly 100% compliant to maximize the health and weight loss benefits of The Paleo Diet. So there’s a continuum of how compliant you should be with Paleo to improve your health, depending on your genetics and where you’re starting from

Over the last few months there has been a bit of a controversy with the issue of pink slime. What are your thoughts on the topic?

For readers who are unaware of the pink slime controversy, I refer them to an informative and up to date article on Wikipedia discussing the topic: http://en.wikipedia.org/wiki/Pink_slime

I believe that this additive should be banned from being included in ground beef worldwide, and that people consuming Paleo Diets should strive to replace fed lot produced meats with pasture or grass produced meats.

The Archives of Internal Medicine recently published a study by Dr Frank Hu, which argued that regular consumption of red meat, especially processed meats, contributed to premature deaths. Do you agree with the findings?

(Pan A, Sun Q, Bernstein AM, Schulze MB, Manson JE, Stampfer MJ, Willett WC, Hu FB. Red meat consumption and mortality: results from 2 prospective cohort studies. Arch Intern Med. 2012 Apr 9;172(7):555-63.)

First of all, for the non-scientists who read this interview, they most likely will not know that the study by Dr. Hu and colleagues represents a descriptive epidemiological study. This type of experiment can never show causality, only relationships between variables.

So, it cannot be logically concluded from this scientific article that red meat consumption causes increased mortality. The only conclusion that can be inferred from this study is that an association exists between red meat consumption and mortality.

The problem with prospective cohorts and all descriptive epidemiological studies are confounding variables, which may interact with the variable of interest to prevent the correct interpretation. Hence, the relationship between red meat consumption and deaths (mortality) from all causes may have resulted from other lifestyle factors associated with red meat consumption but not by red meat consumption itself.

Further, the results of this paper only represent 2 cohorts (groups of people). More powerful epidemiological studies are called meta analyses in which all previous epidemiological studies are combined and collectively analysed.

To date I know of no meta analyses of prospective cohorts that have been published examining red meat consumption and all cause mortality. Numerous meta analyses exist for mortality from a certain diseases (cardiovascular disease, type 2 diabetes, various cancers etc.) and red meat consumption.

The results of these meta analyses are equivocal – meaning that some show increased risk while some do not. Here is a perfect example from a meta analysis examining red meat consumption and the risk of heart disease, stroke or type 2 diabetes. The citation is listed below:

Micha R, Wallace SK, Mozaffarian D. Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus: a systematic review and meta-analysis. Circulation. 2010 Jun 1;121(21):2271-83. Epub 2010 May 17.

Here are the authors’ conclusion: “Consumption of processed meats, but not red meats, is associated with higher incidence of CHD and diabetes mellitus.” Note that these scientists are part of the same research group at Harvard as Dr. Hu.

My feeling is that red meat consumption under the umbrella of the typical western diet (high in refined sugars, refined carbohydrates, omega 6 rich vegetable oils, salt, low in fiber and fruits and vegetables) probably increases overall mortality. I also believe that processed meats (salami, bologna, frankfurters, sausage, bacon etc) are considerably more dangerous than fresh red meats and should be avoided by Paleo Dieters.

I believe that red meat consumption under the umbrella of the typical western diet (low in fresh fruits and veggies) increases the risk for colorectal cancer because of the heme (a form of iron) content or red meat. Heme iron promotes the formation of carcinogenic N-nitroso compounds in the gut.

However, vitamin C and other antioxidant phytochemicals and compounds found in fresh fruits and vegetables are known to prevent the formation of these toxic compounds. Hence, for Paleo dieters who eat loads of fresh fruits and veggie, red meat will represent little or no risk for colorectal cancer.

Finally, to your book, “The Paleo Answer: Seven Ways to Lose Weight, Feel Great and Stay Young.” Do you think there is a reason why a CrossFitter should purchase it?

My day job is as a professor and scientist at a Division I research university. So, the majority of my writings are scientific in nature. In my popular books I attempt to make nutritional science easily readable to people who are not scientists.

By the time (January 2011) I began work on “The Paleo Answer”, the Paleo concept had become huge worldwide and had fractionated into many groups: some who say Paleo can be dairy; some who say Paleo can be salt; some who say Paleo can be this, Paleo can be that. So I wanted to definitively show the science behind what Paleo really was if you want to be pure Paleo.

Now I’ve never said people have to be pure Paleo, but if an argument ever came up where someone says that Paleo people ate dairy and dairy is ok – no. Or Paleo people were vegan or vegetarian – no. Or Paleo people regularly ate grains and legumes – no.

So I wrote specific chapters on each of these topics and many other topics involving subtleties of the Paleo Diet and lifestyle that had previously not been addressed by any of the other competing books on Paleo.

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You can find more out about Dr. Cordain on his website: The Paleo Diet here

If you are interested in Dr Cordain’s new book, “The Paleo Answer: Seven Ways to Loose Weight, Feel Great and Stay Young” you can find it on Amazon.com here