n my first year of engineering school, I pledged a fraternity. Having a group of like-minded people invite you into their organization and actively attempt to secure your membership feels good. They and I seemed to share the same values, principles and goals—my priority being academic, of course—and they offered me something I never achieved in high school, a community.
Luckily, in engineering school, fraternities don’t haze. The brothers organized a party and we pledges performed some team building exercises through the night, which turned out to be little more than a scavenger hunt. After that night, I proudly wore the abbreviation of our once secret society and for the first time in my life, enjoyed being part of a tribe.
After a few months, however, I realized the discordance between the fraternity’s priorities and mine. They did value academics, but the rules and minutiae of the tribe trumped all else. The tribe came first. The first day the fraternity reprimanded me for missing a meeting for academic reasons—because I was writing a 40 page lab report due the next morning—was the last day I called myself a pledge.
I brooded over the decision for days. The people in the fraternity justified the difficulty I had leaving. After I left, they kept their doors open to me, allowing me to use the house for study, attend all parties and—the greatest statement of their character—they remained my friends.
I left the fraternity because our goals didn’t match. I needed a community who would support me in my academic career and whom I would also support. The fraternity, I understand now, needed people dedicated to the institution, placing themselves and their needs second to the doctrine, procedures and image of the group.
This same ideology divides me and Paleo. Paleo wants you to adopt a certain set of rules and force a certain context onto your life. They then promise if you do so, you should get healthy and maybe perform better. This is mandated by the mismatch hypothesis: there is a discordance between our genes and our environment, therefore, you must radically change your environment, i.e. become more Paleo.
In contrast, I only care about helping a person achieve their goal, whether it be health, performance or even aesthetic, and normally end up improving each. I will shape my advice to match the context of their life. My only mandate is that you should be achieving your goals. To make this difference salient:
If you aren’t getting the results you desire, Paleo suggests you worker harder at being Paleo and the results will happen. In the Body IO community, if you aren’t getting the results you desire, I suggest we tweak the methods, not your life, until you reach the desired goal.
This is the difference between an organization being doctrine-driven (Paleo) or goal-driven (Body IO).
If your goal is to be a part of the Paleo Community, then you don’t need to read further. I understand the social need to belong to a tight-knit supportive group. The Paleo Community will help you and support you in your quest to be Paleo.
But if your real goal is simplicity in achieving vibrant health or peak performance I offer you an analysis of Paleo in this article series. I share why Paleo is unproven, whimsical, unscientific, inadequate and has gone so far into the realm of myopic doctrine that it may be causing harm, particularly to children.
The statements below represent a ubiquitous set of Paleo advice and doctrine. I share why each is fallacious.
FALSE: Humans have been in a genetic holding pattern for the last ten to twelve thousand years.
I would like to believe that I am an advanced human being, benefiting from evolution over the last 100,000 or even ten thousand years. Paleo believes civilized humans are a genetic throwback, that we’re all “Stone-Agers in the Fast Lane” of modern times.
The Paleo community promotes the idea that human evolution runs at a snail’s pace and has been, is and will be forever constant. They give no justification for this stance; they simply state it as if it’s common sense. Genomic evidence, however, says otherwise.
Dr. John Hawks and colleagues performed a significant and detailed analysis of the changes human DNA underwent over the last 40,000 years and determined that increasing population size and density increased the speed of human evolution as much as 100 fold. In other words, what used to take 100,000 years for adequate adaptation now takes 1000(a specific historical instance of this appears later).
Hawks also demonstrated that our evolution may still be accelerating. Genomic data concerning food flexibility and diversity in humans also supports this conclusion[5-9]. Since large-scale agriculture began nearly eleven thousand years ago, humans—at least those with a Western European or South American descendancy—have had ample time to evolve to grains and many other Paleo-scorned foods.
Stopping to consider this evidence makes the conclusion of accelerating evolution more sensible in terms of Darwinian evolution than does the idea of a set, universal rate. Environmental pressures, population size and cross-regional breeding drive evolution. As populations grew, interacted more often, had greater chances of beneficial mutations with new challenges to overcome, evolution got a boost.
Bottom Line: Environmental pressures have been accelerating for millennia and they continue to this day. So does our evolution.
FALSE: The Paleolithic Era hardcoded human feeding behaviours and dietary needs into our DNA, which is the only thing defining a healthy human diet.
In my schema of health, a key pillar is rapid adaptability to short-scale environmental changes, i.e. moving from San Francisco to Mumbai might cause a bit of a dietary hiccup—and some diarrhea—but within a relatively short amount of time, a healthy person will adapt and maintain their level of health. Paleo would have us believe this is impossible for modern humans.
High rates of adaptability or flexibility implies that no “wisdom of the body” exists causing us to seek foods based solely on physiologic needs, as Paleo suggests. Many factors establish dietary flexibility: pre-natal nutrient exposure; early post-natal nutrient exposure; DNA methlyation that controls gene expression (so called epigenetics); and a cognitive feedback loop that selects foods based on social, emotional and nostalgic cues.
Inflexibility, therefore, is not defined by some ancient DNA blueprint, but rather cultural and social norms. That modern people suffer disease at a greater rate than say the early 1900s is due more in part because of the limited and inappropriate food offerings given us as children than a hypothetical food environment mismatch.
I’m not blaming parents, but this is a societal issue that needs to be addressed through education and a broadening of the food landscape available to parents and children rather than a contraction. Yes, children should be exposed to all foods early in life—including some junk—so that they can adequately cope as adults (the key word is exposed and does not imply kids should eat junk foods regularly).
The Paleo codec, however, suggests limiting foods given to children to a small subset of evolutionarily appropriate items. In doing so, Paleo is suggesting we create a generation of children who will find the modern food landscape impossible to endure in a healthy manner.
Bottom Line: A healthy diet depends on your culture, early diet, and social interactions, not those of cavemen and women.
FALSE: Sugar is absolutely addicting, as defined by our Paleolithic DNA.
As much as we’d like to blame something simple, like too much sugar in the diet for our current health concerns—thus preserving the ability to eat potatoes, yams, squash and white rice to excess—the science of the matter is far from black and white.
Response to sugar is, again, almost completely determined by environmental factors that can override our genes. We develop an affinity for sweet tastes in utero, i.e. if your mom ate a lot of sweets during pregnancy, you’re born with an enhanced craving for sweets[12-17]. We further the craving by giving children more sweets after birth: fruit, fruit juice, soft breakfast cereals and so on.
Once this association is made, it is compounded by changes in sweet-taste perception with further biological and environmental cues. Stress, in particular, can increase the pleasure response of sweets through hormonal imbalances of ghrelin, leptin and sex hormones. As we fail to control stress in our environment, or are unable to, the preference for sweets we developed as children leads us to seek them out, thus causing a vicious positive-feedback loop.
If we examine the relationship between sweet perception and the human body, we see that humans evolved a long and complex relationship with sugar as Dr. Rocky and I discuss in this podcast [Body IO® FM #35 ]. To summarize, the entire digestive tract contains sweet receptors as do pancreatic beta cells. Clearly, the human diet contained sugar for a long time or we adapted rapidly and successfully to its inclusion in the human diet.
Bottom Line: Sugar is not inherently addictive, but as a society, we have made it so, and we’ve provided free, unfettered access.
FALSE: Humans have a single Paleolithic heritage, and therefore Paleo is a one-size-fits-all protocol.
My genetic background spans several differing cultures from Scandinavian, Germanic, Mediterranean, Persian to Native American and I might even have some genes from prehistoric Siberia. I am a classic American mutt. The Paleolithic populations that spawned my lineage lived in isolated environments, ones containing different foods and foods in varying abundance. They would not have crossed paths often. The question is then, which prehistoric food landscape is the appropriate one for me[18-19]?
Our choice of which past is most appropriate becomes muddled further when we take into account the comingling of cultures, accelerating human evolution and epigenetics. Which adaptations or maladaptations did I acquire from each lineage?
Regardless of such ancient influences, how did my mother eat when she carried me in her womb, was she stressed, and what did my parents feed me after birth? Even my recent ancestry impacts how I might need to eat: did my grandparents or even great-grandparents ever suffer a period of prolonged starvation[22-25]? Which epigenetic advantages or disadvantages did my earliest food exposure create?
The answer to all of these questions bears relevance to determining my ideal diet, the breadth of foods I can consume safely, the macronutrient composition I can tolerate and the appropriate timing of different foods. I will not find the answer by looking 100 thousand years into an unknowable past.
Paleo suggests that we all share a single point of evolutionary origin in the Paleolithic area. Genetic studies of gene flow show this is not the case, and we must look much further into our histories to find a single dietary origin. The best unified current evidence suggests we ate a lot of animals[26-33] once we left the grasslands of Africa. A picture of the unified base human diet would be the picture of a slaughtered Wooly Mammoth.
Each of our dietary adaptations and divergence from the all-animal diet likely happened during the Neolithic period, as is evidenced by the number of alleles that encode for the amylase enzyme (allowing us to efficiently digest starches) and the genes for lactase persistence[6-9], the trait that allows us to digest dairy throughout our adult lives and not only in infancy.
Bottom Line: Looking at Paleolithic menu options won’t tell you anything about what is healthy for you to eat in the modern age.
FALSE: Observing modern Hunter-Gatherer societies helps us define the healthy modern diet.
Before I became embroiled in all things Paleo, I read a book back in 2008, The Jungle Effect: A Doctor Discovers the Healthiest Diets from Around the World, by Daphne Miller, in which she walked the reader through exotic world travels to so-called disease cool-spots to observe the isolated populations and determine the healthiest diets in the world.
Many researchers study the eating habits of isolated hunter-gatherer populations in an attempt to understand the dietary origins of civilized humans. The researchers possess the same preconceived notion that Daphne Miller carried with her around the world: the modern hunter-gatherer lifestyle must mimic ancient human life and, more importantly, ancient human dietary habits. The premise for comparison fails for several reasons.
First, we cannot extrapolate observations on modern hunter-gatherers eating habits and their resulting health to dietary interventions in civilized humans and expect to get a priori the same results.
Civilized humans evolved a robust capacity for dietary flexibility. Isolated hunter-gatherer tribes, despite some contact, have little genetic diversity across their population but possess large genetic differences compared to modern humans (and each other)[34-44]. They could not be fit or healthy on a modern diet because they evolved on a specific non-modern diet.
One population makes this point clear: the Aboriginals of Australia. When suddenly introduced to modern diets, they quickly accumulated body fat and acquired diabetes and other Western metabolic diseases. Reverting back to their ancestral diets reversed the symptoms. Their population never developed the dietary flexibility of civilized humans who benefited from accelerated evolution of dietary flexibility. Their genome simply can’t handle the sudden change.
We should note that we cannot use populations like the Pima Indians of North America and Aboriginals of Australia as examples of how carbs make us fat. Their quite spectacular short term response to these dietary changes do not stem solely from the carbohydrates, but their lack of genetic dietary flexibility.
Second, Paleo enthusiasts cherry-pick modern hunter-gatherer populations for proof, the same behavior for which they lambaste Ancel Keys (the referenced article is a supplement and did not, therefore, undergo academic review). If Paleo authors want to defend dietary meat, they reference the Inuit; sweet potatoes, Okinawans, two genetically diverse groups.
Modern hunter-gatherer diets—from a more inclusive sampling of hunter-gatherer tribes than reviewed in —span a wide spectrum of macronutrient ratios (from 3% carbohydrate to 50% carbohydrate) and grain consumption without incident of disease. Again, the key factor is their long term adaptation to their niche diet. Just as the Aboriginal fails to thrive on a carb based diet, the Okinawan would likely suffer on a diet composed of all meat and animal fat.
A third issue, when observing modern hunter-gatherers, is to ensure correct identification of the group. Things are not always as they appear. Some modern hunter-gatherer tribes turn out to be from an agriculture background—they were farmers in the near past, say the last 500 to 800 years—that reverted to hunting and gathering when they could no longer support themselves with farming. Observational studies not benefiting from genetic data could mistake contemporary hunter-gatherers who do not accurately represent a true pre-agrarian based lifestyle.
There is one final reason why Paleo falters in logic and suitability when using modern hunter-gatherers as a model for human nutrition. To do so assumes we all recently evolved from a hunter-gatherer past, and were thrust into an agriculturally based environment with detrimental consequence. For those of us with European backgrounds, our closest Neolithic ancestors (those more closely defining our adaptive food behaviour) were not hunter-gatherers.
Although mitochondrial DNA evidence suggests that hunter-gatherer populations did expand to cover the European landscape after the last Ice Age (from between 25 thousand years ago to around 11 thousand years ago), the genetic evidence reveals that early farmers invaded these areas and dominated[50-52] (the same events also happened in the human colonization of the Japan).
Today, our genome contains little if any residue of Paleolithic hunter-gatherers. We thrived for thousands of years precisely because we are adapted to agriculture. The hunter-gatherers either dwindled in number into oblivion or Neolithic farmers partially incorporated them into their society where the last of their hunter-gatherer genes—and dietary limitations—faded from existence.
The majority of humans in the First World evolved from farmers highly adapted to agriculture, not poorly adapted hunter-gatherers.
Bottom Line: We evolved from Neolithic humans well adapted to agriculture and possess a diverse, modern genome—one highly selected for dietary flexibility—therefore observations of isolated genetically divergent hunter-gatherers cannot inform recommendations for a healthy diet.
References (click to expand)