One of our natural tendencies as humans is to accept the world around us as “normal”. This doesn’t just apply to the environment we can see with our naked eyes, but also to conventional ideas and beliefs that are commonly held in contemporary societies. Conventional wisdom and official public guidelines are by many viewed as the starting point by which to compare other information, and behaviours, concepts, and ideas that deviate from this baseline are frequently labeled as strange and off-base. The Paleo Diet – the diet that dominates on this blog – occasionally get lumped into this category, as it goes against conventional dietary wisdom in several respects.
The Paleo Diet has experienced a surge in popularity the last couple of years, and most people like the idea of eating a “natural”, unprocessed diet. However, as expected for anything “new” and unorthodox that gains traction, some criticism has also followed. Getting some discussion going is great, as it helps us get a better understanding of human nutrition, but some of the things that are printed, such as the occasional labeling of the Paleo Diet as a fad diet, just come across as ignorance towards genetics and the evolution of the human diet…
Have we learned from our mistakes?
The evolutionary history of man is filled with conventional wisdom that dominated at a certain time in history and then became dismissed as flawed or incorrect at later times. Although we might think that we modern humans are in another league, I personally think there’s little to suggest that we’ve learned from our mistakes and become so much wiser over the years. We don’t even have to go back more than a few decades to see this in action. Not long ago, smoking was considered by many to be completely harmless, a notion that largely came to be as a result of massive ad campaigns that drove home the message that cigarettes are safe and trendy, as well as tobacco executives who covered up documents on the adverse effects of smoking.
There are several other examples of this type of deliberate deception of the public. However, in general, I don’t think the flawed conventional health wisdom that dominates in our society is primarily shaped by “evil” top leaders, but rather by inadequate knowledge, low-quality research, teachers who simply pass on what they learned 40 years ago to their students, an inability to learn from our past, and as mentioned in the beginning, our natural tendency to just accept the world around us as normal.
Let’s take the Human Microbiome for example. One doesn’t have to go back more than a couple of years to get to a point where the trillions of microorganisms that colonize the human body were largely ignored in the field of health & medicine, and those who suggested that disorders such as acne vulgaris, autism, and irritable bowel syndrome were largely caused by “leaky gut” and dysbiosis were labeled as quacks. Fast forward to today and there are thousands of research articles listed in PubMed showing a link between perturbations of the microbiota and pretty much every chronic health disorder under the sun. It’s still going to take years before information and treatments really get out to the general public, as it takes time for new information to make its way into medical studies, because many health practitioners cling on that what they’ve always done instead of actively following the latest research, and since the development of new treatments often takes years.
If we shift our attention over to the Paleo Diet, some of the previously mentioned principles apply. Since cereal grains and dairy products have been such a natural and large part of human diets since agriculture started to spread around the globe, a grain-based and dairy-rich diet have become the norm, and most people simply accept this type of diet as the “natural” human diet. This notion has been further imprinted in people’s minds through national food pyramids, which are largely based on flawed science, and official dietary guidelines, where wheat, barley, rye, and other cereals are advocated as staples. Also, the fact that few nutrition students even hear the terms evolutionary biology and Paleolithic nutrition have further contributed to making conventional dietary wisdom into what it is.
Expanding our perspective
So, how can we avoid repeating the same types of mistakes that have leaved marks on human history? As you know if you’ve been reading this blog for a while, I think a good first step is to expand our perspective by looking at health & fitness through the lens of evolution.
During the Paleolithic era (2.6 MYA-10.000 YA), hominins lived as foragers that subsisted on wild animals and plant foods. hominins lived as foragers in various and diverse ancestral environments, there clearly wasn’t one universal Paleolithic Diet consumed by all tribes. This is especially true following our species’ migration out of Africa 50.000-100.000 years ago, as this journey lead our ancestors into habitats that differed markedly from the African savanna. However, everyone ate some form of a Paleolithic Diet, and a hunter-gatherer lifestyle was the norm.
DNA analyses have shown that all modern humans share a common ancestry. The most recent woman from whom all living humans today descend, Mithocondrial Eve, and the most recent male, Y-chromosomal Adam, are estimated to have lived between 100.000 and 200,000 years ago, somewhere in Africa. We were all once foragers in the wild, and although we now wear suits and dresses and drive around in fancy automobiles, our genetic heritage is still with us.
For millions of years, our digestive system, metabolism, and teeth evolved to match a diet of meat, tubers, fruits, honey, and other foods available in the wild; a concordance that was abruptly lost when large amounts of starch, novel secondary metabolites, and ultimately ‘junk food’ were introduced in the human diet.
The important thing to remember is that grains and dairy products only became a significant part of the human diet approximately 11.000 years ago – and many places in the world also much later than this. Compared to the millions of years we’ve been eating from the food groups that make up preagricultural diets, this is just a small drop in the pond.
From an evolutionary perspective, it’s the modern, grain-based and starch-heavy diet that is the fad.
Here are the facts:
- The Paleo Diet is the Original/Default Human Diet
- Humans don’t have a nutritional requirement for grains and milk. This is actually a given, as these foods were not a part of human diets (except for very small quantities) up until the Agricultural Revolution.
- No other free-living primates routinely consume cereal grains, and to my knowledge, no wild animals regularly drink the milk of another species. In itself, this doesn’t tell us that we shouldn’t consume these foods, but as every Paleo dieter knows, and as I’ve outlined on the diet page and elsewhere, these foods come with some potential downsides.
- The Paleo Diet has all of the traits that characterize a healthy diet.
The main point of this article is that we have a tendency to look at the current way of doing things (e.g., eating a high-carbohydrate and grain-based diet, sleeping in one concentrated bulk each night) as the baseline for what is “normal” behaviour for humans. However, if we broaden our perspective and look at things through the lens of evolution, it quickly becomes clear that our Paleolithic ancestors’ way of life in ancestral natural environments functions as a far better baseline. Why? Because 99.5% of the evolutionary history of our genus (Homo) consists of a hunter-gatherer existence in the wild. This doesn’t mean that everything that is new to today’s society should be avoided, or that foods that have been introduced after the Neolithic Revolution should be shun like the plague. Of course not. It simply means that the evolutionary template provides the foundation we need to build everything else upon.
In affluent societies, cultural buffering of evolution’s harsh rule of “survival of the fittest” has slowed down the process of Darwinian evolution. In other words, we’ve created an environment where most people – regardless of physical fitness levels – can survive and reproduce. Chronic health disorders, such as cardiovascular diseases, cancers, and overweight, are widespread, but these conditions typically only have negligible effects on reproductive fitness. What this means is that natural selection no longer operates as strongly as before, and hence, it takes a long time for genetic adaptations that allow us to better thrive on modern diets to increase in frequency in a population.
We’re still very much Stone Agers from a genetic perspective, and as long as this continues to be true (which is for the unforeseeable future), a Paleo-based diet is the type of diet that is best aligned with your genetics!