Diets come, and diets go. And like fashion, if you wait long enough, what is now out will eventually return — but with a twist, so you can’t dust off the old books, but instead have to buy new ones.

And when you think about it, that only makes sense. After all, food really falls into one of only three groups: proteins, fats, and carbohydrates. So all diets are pretty much restricted to mixing things up within those three groups — thus the repetition. Ahh, but given those limitations, there is still infinite variety — thus the ever new diet programs.

And now it is the turn of the Paleo Diet (also known as the Paleolithic Diet, or Caveman Diet) to sweep the nation. In fact, the Baseline of Health Foundation has been literally bombarded with requests for me to explore the topic over the last several months. But in truth, it’s not actually new. It was first popularized by Walter Voegtlin in the 1970’s and is close cousin to the Atkins diet and the Meat Lovers Diets that rose to popularity about ten years ago. And in truth, there is much to like in the diet, but also some things that give me pause and a couple of “are you kidding me’s” along the way.

With that in mind, let’s take a look at the Paleo Diet.

The theory behind the Paleo Diet

As I mentioned, the Paleo Diet has its roots in Walter Voegtlin’s book, The Stone Age Diet, which was published in the mid 70’s. Originally, it was referred to as the caveman diet, or the stone age diet. “Paleolithic,” by the way, is just the scientific term for “old stone age.” The theory is that without access to modern diets, cavemen ate more naturally than we do today. They didn’t eat Twinkies® and chips and Big Macs®. They were hunter-gatherers and ate as the human body was designed to eat…theoretically. They had no agriculture, no storage facilities, no grocery stores, and no processed foods. They ate wild plants and fresh meat as they found it.

And they were healthy…again, so the theory goes. There was no arthritis, no cancer, no osteoporosis, and no heart disease. They were strong-boned, hearty and healthy, and if they died young, it was not because of disease but because of accidents and a hard environment. Otherwise, they were all veritable Methuselahs. And although there are few remains of cavemen to verify the claims, there are a couple of small studies that do indeed show health benefits for those who follow the diet.

But mostly there are testimonials. Now please understand, I do not make light of testimonials. I find them potentially as valid as many so-called scientific studies. However, I am quite aware of how testimonials can be ruled by emotion and run totally out of control, totally invalidating themselves. Another problem is that when giving testimonials, people tend to generalize their experiences — if I feel better because of it, then everyone in the world will feel better. That said, the primary argument on behalf of the Paleo Diet is that there are select populations living in the world today that have followed the Paleolithic diet for generations and show none of the signs of modern disease…maybe.

For about 30 years, the Paleo Diet struggled along, taking a back seat to the Atkins Diet®, the Blood Type Diet, the Nutritional Type Diet, Jenny Craig®, Nutrisystem®, the Hollywood Diet®, Volumetrics®, the Mediterranean Diet, the South Beach Diet®, the Carb Lovers Diet, and on and on. It was not until 2005 that the Paleo Diet came into its own, with the publication of Loren Cordain’s The Paleo Diet for Athletes: A Nutritional Formula for Peak Athletic Performance. With athletes beginning to endorse the diet, it gained momentum, hitting the big time in 2010, with the publication of Cordain’s next book, The Paleo Diet and Rob Wolf’s book, The Paleo Solution.

So what exactly does the Paleo Diet advocate, and is it as good as claimed?

The tenets of the Paleo Diet

The primary tenet of the Paleo Diet is that diets and health started to go downhill the moment agriculture started to gain traction. Farming, the foods it produces, and food processing — which are the cornerstones of the modern diet — are the enemies of health. If you want to be healthy, you have to eat the diet your body was designed for — the diet that cavemen ate, the diet that is natural to man. Of course, what that diet actually is, is open to question. It’s not as if Grog the caveman left behind cookbooks. Cave paintings, yes! Cookbooks, no! And of course, the diet has to make do with certain “alternatives” since fresh, grass-fed mammoth meat is no longer available for the killing right down the street.

To summarize, the Paleo Diet is based on what we “think” cavemen ate, based on some historical data and studies of modern-day hunter-gatherers, as well as trace evidence found in archeological digs and a whole lot of guess work and theory. And since true caveman foods are no longer available to us, it is also based on modern food “equivalents” that have been refined over centuries and that are commonly available in today’s supermarkets. That means that, for the most part, the meat you eat comes from domesticated animals raised using modern mass production methods, even if grass-fed, and the so called “forage” that you eat is based on cultivated hybrids nurtured on artificial fertilizers and possibly pesticides.

But that’s only part of the story. The Paleo Diet is defined as much by what you cannot eat, as by what you can eat. Or more specifically, the philosophy behind the diet is that you are only allowed to eat what was “natural” to the human diet during the Paleolithic era, not the “artificial” foods that have been added to the diet since then as a result of the agricultural revolution and the introduction of urbanization and mass manufacturing.

That means that all crops that only became viable parts of the diet because of the agricultural revolution (grains, beans, and peanuts, for example) and the byproducts of domesticated livestock (i.e., dairy) are taboo. Sugar is not allowed. And alcoholic beverages and fermented foods are also off the table. Incidentally, I find this particularly amusing since alcoholic beverages and fermented foods seem to have been part of man’s diet since the beginning of time. As Bob Dylan once sang, “Everybody must get stoned.” But forget about cavemen, as it turns out, the consumption of alcoholic over-ripe fruit for the purpose of getting blitzed predates even the first cavemen and is common to many species. See for yourself how animals find ways to “party hearty” without a brewmaster in the bunch by watching this video.

I think it’s pretty much safe to say that if Paleolithic men and women abstained from alcohol, they would have been pretty much alone in the practice — which brings up an interesting contradiction in the Paleolithic diet. If cave-people ate fermented foods, and yet you choose to exclude those foods from the Paleo Diet, which is supposed to be based on what they ate, then you’ve opened up a fundamental hole in the logic behind the diet. But there’s no need to dwell on that now.

One problem we face when looking at the Paleo Diet is that there are multiple versions of it among its many adherents. For example, some insist on organic, grass-fed beef, others barely mention it. Some say no oils are allowed. Others say low omega 6/high omega 3 oils such as canola oil are okay. And others disagree as to which fruits and vegetables are allowed. This brings up a second fundamental problem when discussing the Paleo Diet, with so many variations, what exactly is it? But in general, here is a list of the do’s and don’ts of the Paleo Diet.

No grains, beans, potatoes, or dairy

This is numero uno! As the theory goes, for millions of years, humans and their relatives ate meat, fish, poultry, and the leaves, roots, and fruits of many plants. That was their natural diet, and that was their sole diet. Grains, beans, and potatoes were not eaten because uncooked, they are inedible — in fact, according to the theory, they are toxic if eaten raw. (We’ll get back to this later, because it’s actually not quite true.)

Around 10,000 years ago, two things happened that changed the way we eat. First, humans learned that they could eat the three demon foods — grains, beans, and potatoes — as long as they are thoroughly cooked. Cooking destroys “most” of the toxins that made them inedible. “Most” is the important word here for Paleo’s. In any event, these discoveries changed the course of history. No longer did people have to chase animals across the plains and scavenge for roots and berries in harsh winter landscapes. Now they could grow food, store it in granaries for times of famine, and have a source of abundant calories in a stable environment.

In addition, they could start raising herds of animals and introduce dairy products into the diet. Once the hunt for food was no longer the driving factor in life, people could devote themselves to the things that make for civilization: science, the arts, building cities, gangsta rap, and war. This is the point in history that divides Paleolithic man from modern man (or so the theory goes).

Continuing on!

Unfortunately, according to the Paleo diet, our bodies are not designed to handle these “new foods.” We’re not genetically equipped to handle a diet heavy in grains, legumes, and potatoes. And the development of the culinary arts has only exacerbated the problem by introducing salt and sugar to our diets. And now, with the introduction of artificial flavors and colors, preservatives, pesticides, excipients, and whatnot, it is more than our bodies can handle. Chronic illness and obesity are the inevitable result.

So what do grains, beans, potatoes, and dairy have in common that makes them so unhealthy that we have been unable to adapt to them over the last 10,000 years? Two things according to the theory: enzyme blockers and lectins.

Plants use enzyme blockers to stop plant seeds from sprouting prematurely. And lectins are natural pesticides used by plants to defend against bacteria, insects, worms, rodents, and other pests that threaten their existence. And when you think about it, from the plants’ POV, humans are just another pest that threatens their existence — and thus lectins, defend against people too. Theoretically then, plant lectins are harmful to people.

As for dairy, milk contains lectins because the cows eat foods that contain them — and so they are passed on in the milk. I know that the Paleo banishing of milk will certainly draw the ire of the raw milk aficionados who regularly write me espousing the virtues of raw milk — most of which I acknowledge. But I find that complaint secondary to the fact that lectins are present in meat for the same reason they’re present in dairy — because the cattle eat them as part of their diet. So if you can’t have dairy for that reason, how does meat get a free pass?

In any case, this argument is somewhat specious since every living thing has defense mechanisms to protect itself from being devoured by predators large and small. For example, humans have immune systems (and antibiotics of their own creation) to defend against bacteria. How can anything “eat” those defenses, figuratively speaking? Because, quite simply, species are constantly adapting to be able to overcome other species’ defenses and so use them for food. It is the way of life. But let’s not dwell on the negatives; let’s move on.

Since lectins are so fundamental to the Paleo Diet, let’s explore them in a little more detail. Incidentally, this is not the first time I’ve explored lectins in some detail. Back in 2007, I discussed the validity of the Blood Type Diet, in which lectins play a prominent role in its theoretical underpinnings — much as with the Paleo Diet.

The problem with lectins

Lectins are carbohydrate-binding proteins that are found in most plants, particularly grains, potatoes, and beans. The problem is that some lectins ape the glycoproteins on red blood cells, thus triggering immune reactions in sensitive individuals. And yes, there is no question that different foods definitely have high allergy potential for many people, but the problem appears to be less with the lectins, than with the ability of the digestive tract to fully break down the proteins in the food.

And beyond that, lectins are not exclusive to plants. All foods contain lectins. Not all are harmful. Some are actually beneficial. In animals, lectins serve a number of biological functions, from the control of protein levels in the blood to removing harmful glycoproteins from the circulatory system to recognizing carbohydrates that are found exclusively on certain pathogens and thus targeting them for elimination.

For example, guava lectin may be useful in the prevention of E. coli infection of the gut.1 Even better, some studies have shown that lectins can neutralize cancer cells. Soy and peanut lectins appear to be particularly good in this regard.[2]

But not all lectins are good. Curiously, soy and peanut lectins, which may target cancer cells, are also among the most allergenic lectins in nature. One lectin with an especially bad rep that has been much in the news over the last few years is gluten. Like most lectins, gluten is resistant to stomach acid and digestive enzymes and does not break down easily in the gut. Once in the gut, it may attach to the intestinal wall and damage its lining. Gluten has been implicated in a whole range of intestinal diseases such as irritable bowel syndrome, colitis, Crohn’s, and of course, Celiac-Sprue. More specifically, gluten, in those susceptible, can break down the surface of the small intestine, stripping it of mucus and causing the gut to leak — allowing undigested proteins to pass into the bloodstream.

According to some proponents of the Paleo Diet, lectins may also play a role in diabetes by tricking cells into thinking they’ve been stimulated by insulin and also by causing the beta cells of the pancreas to release insulin. Yet other lectins may play a role in rheumatoid arthritis by attaching to cell surfaces and tricking the immune system into thinking that cells are actually pathogens, thus triggering the immune system to attack the body — an autoimmune response.

And to be sure, there is no question that certain foods definitely have high allergy potential for many people, but the problem appears to be less with the lectins, than with the ability of the digestive tract to fully break down the proteins in the food. As I’ve discussed in several posts, the use of digestive enzymes with meals and proteolytic enzymes between meals can often help reduce food allergies dramatically. In fact, there is little evidence that lectins, other than a handful of exceptions, present a problem for most people.

To conclude our discussion of lectins, let me offer some perspective. If the argument is that because “some” lectins are toxic to “some” people, then “all” people should avoid “all” lectins, we have a problem. We live in a world where food exists as part of a chain, with predators eating prey – and the prey develops defenses to protect itself from being eaten. Lectins are part of the circle of life and can’t be avoided; they permeate the food chain as predator eats prey. This means that if you wish to avoid all lectins, you would have to avoid all food, since all food contains lectins. To do otherwise implies selective belief in your theory. At least the Blood Type Diet acknowledges this issue and says that at least some groups of people have adapted to eating grains, beans, potatoes, and dairy.

So what should  we eat on the Paleo Diet?

Meat (particularly organ meats such as liver and kidneys), poultry, and fish top the list. Remember, we’re talking about “hunter” gatherers. In fact, according to some proponents, flesh should provide upwards of 65% of the calories in a Paleo Diet, with fruits and vegetables providing only about 35%. Eggs are also big on the diet.

Fruits and vegetables:

Fruit and root vegetables such as carrots, turnips, and beets are okay, but not tubers such as potatoes, sweet potatoes, and yams. Incidentally, I find the exclusion of tubers requires a bit of theoretical bending. The argument is that potatoes are a “new world” crop and humans have only been eating them for maybe the last 35,000 years. But in truth, yams are an African crop that people have been eating since the dawn of time. So why are they excluded? And if that’s your logic for excluding potatoes, then why is turkey okay? After all, turkey is a “new world” species, not even introduced into Europe until the 16th Century. Not that I personally think it matters, but I’m just saying.

As for fruits, berries of all kinds are good — strawberries, blueberries, and raspberries etc. are good. From there, differences in Paleo’s abound. Tree fruits are controversial. For example, some say apples are great. Others call them “bags of sugar.” And still others say they’re okay if you eat the low sugar varieties. And yet, if the theory is based on eating what hunter-gathers ate, then tree fruits would have to be top of the charts. Not to go Biblical, but I think it’s pretty safe to say that tree fruits such as apples and pomegranates have been part of the human diet since the very first man and woman walked the earth. And I don’t believe hunter gatherers selected their fruit based on the glycemic index. Again, I’m just saying.

Also, fruits contain lectins [3] — just like grains. Apricots, bananas, cherries, kiwis, melons, papayas, peaches, pineapples, plums, and even berries are all known to contain lectins and cause allergies. In fact, fruit allergies make up about 10 percent of all food related allergies. So why are fruits allowed? Incidentally, new research has shown that allergies to fruit are actually made possible by pectin, the soluble fiber found in fruit. The pectin surrounds the fruit allergens in the digestive tract so that they don’t get broken down and enter the bloodstream intact. Using a digestive enzyme supplement that contains added pectinase can help moderate that problem by breaking down the fruit pectin, which then exposes the allergens to digestive juices and enzymes.

Nuts and legumes:

Curiously, nuts are cool on the diet — pretty much all nuts except cashews and peanuts, which are actually beans. Yes, I understand that people have eaten gathered nuts since the beginning of the human race, but if allergenic lectins are your thing, nuts should be a “no no.” Tree nuts including macadamia nuts, brazil nuts, almonds, walnuts, pecans, pistachios, chestnuts, hazelnuts, and pine nuts are high in allergenic lectins. And unlike grain allergies, which tend to be low level and chronic, tree nut allergies tend to be severe, and are strongly associated with anaphylaxis and even death. Walnuts (and cashews) top the list for the tree nuts most likely to cause an allergic reaction. Peanuts, incidentally, are legumes, which is why they are on the Paleo no-no list. As legumes, they are biologically unrelated to tree nuts; nevertheless, there is a high level of cross-allergenic reactivity between peanuts and tree nuts. So again, if peanuts are not allowed, why are tree nuts okay? I’m just looking for consistency in the theory behind the Paleo Diet and its application in the real world.

Another factor to consider is that tree nuts have the same enzyme blockers that seeds and grains have, and for the same reason — to prevent premature sprouting. And like seeds, grains, and legumes, those enzymes are neutralized by soaking in water and exposure to heat. But that goes against the premise behind the Paleo Diet. So once again, we have to ask, “Why nuts?”

Incidentally, sprouting nuts will eliminate most of the blocking enzymes as well as many of the allergenic lectins.

Legumes, or beans, present much the same problem. They have blocking enzymes to prevent premature sprouting and toxins to keep predators away. Soaking and cooking will pretty much eliminate that problem, but because they have to be cooked, they violate the “Paleolithic theory” of no cooking and so are not allowed.

Are you kidding me?

I find the theory behind the Paleo Diet to be somewhat distorting of facts and highly inconsistent within its own logic. We’ve discussed a number of those inconsistencies already and will explore several more tomorrow in Part 2 of this post. However, it is important to keep in mind that just because an underlying theory may be wrong does not mean that the program itself is without value.

For example, at one time, people believed that the sun was a golden chariot driven by a god that crossed the sky — a theory that many scientists now believe to be flawed. Nevertheless, belief in that flawed theory didn’t stop ancient peoples from being able to track the sun so accurately that they could determine the vernal equinoxes to the day hundreds of years in advance — knowledge essential for agricultural societies.

So once again, let me state that theory aside, the Paleo Diet has much to recommend it.

In Part II of this discussion we examine a few more of the theoretical inconsistencies in the Paleo Diet as well as my specific recommendations. Click here to read Part II.

References:
1. Peter D’Adamo. “Fruit Lectins and E. Coli.” Ask Dr. D’Adamo. Eat Right for Your Type. 3 May 2011.
2. Peter D’Adamo, Catherine Whitney. “Eat Right for Your Type.” G.P. Putnam’s Sons. 1996. P 318
3. Roci´o Coutiño-Rodriguez, Pedro Hernández-Cruz, Héctor Giles-Rios. Lectins in Fruits Having Gastrointestinal Activity: Their Participation in the Hemagglutinating Property of Escherichia coli 0157:H7. Archives of Medical Research. Volume 32, Issue 4, Pages 251-257 (July 2001).
4. Katharine Milton. “Hunter-gatherer diets — a different perspective.” American Journal of Clinical Nutrition, Vol. 71, No. 3, 665-667, March 2000.

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