The Thing That Separates Paleo From All Other Health/Nutrition Concepts

The Thing That Separates Paleo From All Other Health/Nutrition Concepts

By guest author Eirik Garnas, Darwinian Medicine

Eirik Garnas is a nutritionist (B.Sc. in Public Nutrition, M.Sc. in Clinical Nutrition), science writer, personal trainer, and health coach. He has several years’ experience with health/nutrition coaching and personal training and has written for a variety of different magazines and websites. On his website Darwinian-Medicine.com Eirik writes about health and fitness and talks about the origins and solutions to different diseases and health problems.



Unless you’ve been living under a rock for the past couple of decades, you’ve undoubtedly noticed that the internet is chock-full of information about diet and health. The non-digital, real world is as well. Thoughts, opinions, and ideas about healthy living circulate in cafés, fitness centers, and classrooms all over the world. One of the characterizing features of this information is that it’s very heterogeneous. Virtually nobody seems to be in complete agreements about anything.

Some YouTubers loudly claim that the key to a lean and mean physique is to adhere to a high-volume, high-intensity strength training program, whereas others argue that a less strenuous exercise routine agrees much better with the human body; some nutritionists make the case that we would all be best off if we ate a vegan or vegetarian diet, while others cherish meat and claim that animal source foods are an essential part of the human dietary template; some medical doctors argue that many diseases and health problems can be prevented via proper diet and exercise, whereas others put all their faith in the pharmaceutical industry; and so on…

Why is there so much conflict and confusion?

As I see it, the answer to this question is quite simple: The reason there is so much conflict and confusion is that there are no guiding principles in place that everyone adheres to. Most people don’t have a guide that helps them safely navigate through the jungle of health/fitness information we all find ourselves in. They simply follow the flock or let their feelings guide them.

This is not to say that no such thing as a guide that can help us travel through the jungle unscathed exist though. The fact is that we do have access to an excellent guide. That guide is called evolution.

The thing that most clearly separates “Paleo” from other health/nutrition concepts is its deep evolutionary roots. The fundamental principles of the evolutionary health concept aren’t just supported by numerous experimental studies, but also by established facts regarding how evolution and nature work. No other health/nutrition concept can make this claim.

I know this may seem abstract to a lot of people, so in order to illuminate what it is I’m talking about, I thought I’d briefly try to explain what I mean when I say that evolution can help us make sense of what we should eat and how we should live our lives.


The link between health and Darwinian fitness

Back in Paleolithic times, human health and fitness were strongly linked. What I mean by that is that a hunter-gatherer who was overweight, nearsighted, weak, fragile, metabolically deranged, and/or otherwise in poor health would likely have been less capable of surviving and reproducing than a lean and fit hunter-gatherer. It’s not surprising that obesity, myopia, type-1 diabetes, and many, many other diseases and health problems are extremely rare or nonexistent among hunter-gatherers,1, 7 seeing as all of these conditions compromise biological fitness. This is very important to acknowledge, because it helps us make sense of what type of diet and lifestyle we should be adhering to. Unfortunately, it’s something a lot of people, including some evolutionary scientists, overlook.

It’s safe to assume that natural selection favored Paleolithic humans who thrived, health wise, under the conditions they found themselves in, seeing as health status was an important determinant of reproductive success back then. This is not to say that traits that were beneficial in terms of their impact on reproductive success wouldn’t have been favored by natural selection if they were detrimental in terms of their impact on health or longevity. All I’m saying is that it’s not surprising that hunter-gatherers tend to be lean, fit, and metabolically healthy and have strong, dense bones and good eyesight, seeing as these traits are vital with respects to survival and reproduction in a natural environment. Moreover, a person who is chronically inflamed and in poor health is not as sexually robust or fertile as someone who is healthy and fit.

Even hunter-gatherers and traditional people consuming Paleo-style diets who are fairly old tend not to suffer from the degenerative diseases that afflict the elderly in industrialized nations.1, 8 This may largely be explained by the fact that men are capable of reproducing up until old age; hence, it makes sense that the prevalence of inflammation-related, degenerative diseases that undermine organismal fitness is low among aged, male foragers. Women can’t reproduce when they get older; however, they can contribute to ensuring the survival of their genes in other ways, such as by caring for their children and the offspring their children bring into life. Men can also contribute in this regard.

An old woman or man who is fairly healthy is obviously more capable of caring for his children and grandchildren than someone who is sick and fragile. Instead of helping his children and grandchildren survive, the latter person will likely demand a lot of attention and care, and hence, potentially negatively affect the reproductive success of his/her offspring and their offspring.

This brings us over to another very important thing that separates Paleo from other health/nutrition concepts. The Paleolithic era spans a very long time period. It lasted from about 2.6 million years ago to about 10.000 years ago. This is very important to acknowledge, because it implies that it would have been ample time for natural selection to adapt the human body to Paleolithic conditions. Throughout the Paleolithic, the environments in which our ancestors lived undoubtedly changed. Climate shifts and other natural events would have altered the conditions of life. Moreover, over time, our ancestors produced new tools and weapons that allowed them to exploit new resources.

With that said, there are certain characteristic elements that would have been a part of the environment and lifestyle of all Paleolithic humans. First of all, prior to the Agricultural Revolution, all humans subsisted on a diet composed of wild plants and animals. Paleolithic humans consumed varying mixes of meat, eggs, seafood, fruits, vegetables, nuts, and insects. Grains and milk didn’t enter into the human diet in any significant quantities until the Agricultural Revolution.2 Second, all Paleolithic humans would have been physically active. This is safe to assume, seeing as physical activity was a prerequisite for food acquisition back then. Third, our Paleolithic forebears lived in a natural environment. Among other things, they were not exposed to modern technology and lived in accordance with the natural fluctuations in light and dark.

Several recent studies have shown that contemporary humans who take up a Paleo-style diet experience rapid health improvements.4, 5, 9, 10 This shouldn’t come as a surprise, seeing as we’re “genetically wired” for Paleolithic conditions.

The fact is that we don’t need a study to prove that it’s healthy to eat like a hunter-gatherer. All we need is a basic understanding of evolutionary science and some common sense. As pointed out earlier, a hunter-gatherer that’s obese, nearsighted, weak, or otherwise in poor shape is probably not going to make it very long. Hence, it’s not surprising that all of the available evidence suggests that hunter-gatherers are lean and fairly healthy.1, 12

These facts alone prove the validity of the Paleo concept. It’s absurd to say that the Paleolithic diet/lifestyle is an unhealthy diet/lifestyle, seeing as there was a strong link between human health and Darwinian fitness back in Paleolithic times. The genes of a prehistoric hunter-gatherer who didn’t do well on a grain- and dairy-free diet composed of a mix of wild plants and animals or wasn’t fit enough to get a hold of food probably wouldn’t have made it very long.


A new way of life

With the Agricultural Revolution some 10.000 years ago, everything changed. At that time, new foods and pathogens entered into the proximate environment of our ancestors, who took up a more settled existence. 10.000 years may seem like a very long time; however, from an evolutionary perspective, it’s only a blink of an eye. Moreover, it’s important to remember that the Agricultural Revolution didn’t spread across the globe overnight. In some places of the world, it wasn’t until four or five thousand years ago that agriculture took hold.

This is important to acknowledge, because it implies that there has been very little time for natural selection to reorganize the human body so that it matches well with the conditions of life that prevailed following the Agricultural Revolution. Furthermore, it’s important to acknowledge that many of the adverse health effects that accompany the consumption of Neolithic and Industrial foods have little or no impact on organismal fitness, particularly under modern conditions.

For example, if you consume a grain-heavy, starchy diet, you’ll change the microbiota of your upper gastrointestinal tract in such a way that you become prone to developing tooth decay.2, 3, 6 However, by brushing your teeth and regularly getting your teeth checked by a dentist, you can block the proliferation of caries-producing bacteria. You won’t be able to completely protect yourself against the harmful effects the grains you’re eating have on your health, but you’ll at least be able keep your teeth from rotting. Your grain-heavy diet could raise the levels of proinflammatory cytokines circulating in your bloodstream; however, it’s unlikely to majorly undermine your abilities to reproduce in a modern environment. In other words, it’s not going to severely compromise your biological fitness.

This fact, that many of the health problems that accompany modern diet and lifestyle practices have little or no impact on organismal fitness (particularly in modern environments), suggests that we can’t expect natural selection to eliminate health problems such as obesity, type-1 diabetes, and colon cancer any time soon. In particular conditions that typically develop late in the life span are not subject to strong selective forces. Via niche construction and cultural innovation we’ve loosened the bond between health and Darwinian fitness, and in doing so, we’ve “altered” the course of evolution.

Besides adapting over time to environments via changes in the gene pool, organisms can adapt epigenetically to their environments. With that said, there’s a limit to how epigenetically flexible we are. The human genome doesn’t have ready-made phenotypes for every possible environment. It has to work within the confines of reality. There has never been any real time for selective forces to “prepare” the human genome for the novel conditions in which we – contemporary humans – find ourselves; hence, it’s not surprising that a large body of evidence shows that we get sick, fat, and unhappy when we are regularly exposed to environmental agents that were not present in past human environments.1, 7, 11


The bottom line

The Paleo concept is unique in that it conforms to the “rules” of evolution and nature. It’s not surprising that hunter-gatherers are lean and largely free of chronic disease or that industrialized humans who adopt a Paleo lifestyle experience rapid health improvements, seeing as human health and reproductive success were strongly linked back in the day and that natural selection has had ample time to adapt the human genome to Paleolithic conditions.




1 Pedro Carrera-Bastos, Maelan Fontes-Villalba, James H O’Keefe, Staffan Lindeberg, and Loren Cordain, ‘The Western Diet and Lifestyle and Diseases of Civilization’, DovePress, 2011 (2011).

2 L. Cordain, ‘Cereal Grains: Humanity’s Double-Edged Sword’, World Rev Nutr Diet, 84 (1999), 19-73.

3 Louise T. Humphrey, Isabelle De Groote, Jacob Morales, Nick Barton, Simon Collcutt, Christopher Bronk Ramsey, and Abdeljalil Bouzouggar, ‘Earliest Evidence for Caries and Exploitation of Starchy Plant Foods in Pleistocene Hunter-Gatherers from Morocco’, Proceedings of the National Academy of Sciences of the United States of America, 111 (2014), 954-59.

4 T. Jonsson, Y. Granfeldt, B. Ahren, U. C. Branell, G. Palsson, A. Hansson, M. Soderstrom, and S. Lindeberg, ‘Beneficial Effects of a Paleolithic Diet on Cardiovascular Risk Factors in Type 2 Diabetes: A Randomized Cross-over Pilot Study’, Cardiovasc Diabetol, 8 (2009), 35.

5 T. Jonsson, Y. Granfeldt, C. Erlanson-Albertsson, B. Ahren, and S. Lindeberg, ‘A Paleolithic Diet Is More Satiating Per Calorie Than a Mediterranean-Like Diet in Individuals with Ischemic Heart Disease’, Nutr Metab (Lond), 7 (2010), 85.

6 M. I. Klein, S. Duarte, J. Xiao, S. Mitra, T. H. Foster, and H. Koo, ‘Structural and Molecular Basis of the Role of Starch and Sucrose in Streptococcus Mutans Biofilm Development’, Applied and Environmental Microbiology, 75 (2009), 837-41.

7 D. Lieberman, The Story of the Human Body: Evolution, Health, and Disease (Vintage, 2014).

8 Staffan Lindeberg, Food and Western Disease: Health and Nutrition from an Evolutionary Perspective (Wiley-Blackwell, 2011).

9 E. W. Manheimer, and E. J. van Zuuren, ‘Paleolithic Nutrition for Metabolic Syndrome: Systematic Review and Meta-Analysis’, 102 (2015), 922-32.

10 U. Masharani, P. Sherchan, M. Schloetter, S. Stratford, A. Xiao, A. Sebastian, M. Nolte Kennedy, and L. Frassetto, ‘Metabolic and Physiologic Effects from Consuming a Hunter-Gatherer (Paleolithic)-Type Diet in Type 2 Diabetes’, Eur J Clin Nutr, 69 (2015), 944-8.

11 B. Ruiz-Nunez, L. Pruimboom, D. A. Dijck-Brouwer, and F. A. Muskiet, ‘Lifestyle and Nutritional Imbalances Associated with Western Diseases: Causes and Consequences of Chronic Systemic Low-Grade Inflammation in an Evolutionary Context’, J Nutr Biochem, 24 (2013), 1183-201.

12 I. Spreadbury, ‘Comparison with Ancestral Diets Suggests Dense Acellular Carbohydrates Promote an Inflammatory Microbiota, and May Be the Primary Dietary Cause of Leptin Resistance and Obesity’, Diabetes Metab Syndr Obes, 5 (2012), 175-89.



To learn more, visit Eirik Garnas’ website Darwinian-Medicine.com or his Facebook page @darwinianmedicine

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