The assertion that our bodies are better suited and more in tune to the foods eaten by our ancestors popularized the Paleo Diet* & movement, and was outlined explicitly in Loren Cordain’s 2002 book, The Paleo Diet (1).

In their quest for fitness, athletes have adopted the Paleo Diet as a means to optimize their performance. The Paleo Diet advocates a higher intake of protein and fat (especially from free-range, grass-fed sources) and cutting out grains to achieve a lower intake of carbohydrates. Most Paleo Dieters do not consume dairy or legumes, like peanuts. Although it has been embraced by many athletes, the assertion that Paleo is a superior diet has been under scrutiny since 2002, with the controversy over these claims gaining momentum in recent years. From being named the worst diet of 2014 (2), to being scrutinized in peer-reviewed literature (3), critics claim that the diet is hard to follow, lacks scientific evidence for efficacy, and has the potential to cause nutritional deficiencies.

Despite this, the emphasis placed by the diet on the consumption of unprocessed, natural foods seems to be well received by most. Many Paleo Dieters have had incredible transformations (4) on the diet, while others are concerned (5) about how the diet is treating their body. Why is it that some people find more success on the diet than others?

Is the Paleo Diet right for you?

Like any diet or fitness plan, just because it works for some, does not mean it works for all. Modern genetic research has taught us that we respond differently to diets (6) based on our genetic profile, which differs greatly between individuals, and even more when we compare modern Homo sapiens to Paleolithic ancestors.

Fat and Your Genes

As we covered in our previous blog, some people can lose weight with an increased saturated fat intake, depending on their genetic profile at particular markers (7, 8).  However, those with other genetic variations may be more sensitive than the average individual to gain weight as a result of increased saturated fat intake from animal fats and butter (9).

That said, your body responds differently to different types of fat. Depending on your genotype at specific markers, it may actually be beneficial for you to increase your intake of certain fats.

There’s no doubt that fat intake is needed to sustain a healthy lifestyle and peak athletic performance, but some can tolerate it better than others. This is just one example of how an all-encompassing approach to diet may be suboptimal for producing top athletic performance.

The Shift In The Human Diet

Advances in modern research have shown there are discrete genetic differences that alter the response to diet in humans today – and even more so when we compare our genome to that of our Paleolithic ancestors.

Despite the recurring insistence that Paleo is the natural, genetically adapted way that modern humans are supposed to eat, the facts remain that the last 10,000 years (10) have given rise to varying genetic profiles relating to optimal nutrient metabolism.

Interestingly, analysis of Paleolithic migration routes reveal that our ancestor’s areas of relocation would give rise to different dietary intakes. For example, our earliest ancestors, Australopithecus and Homo habilis, thrived on intake of fruits, plants, and vegetables while residing in the rainforests and woodlands of Africa. Evidence shows that meat was later introduced into the Paleolithic diet of our ancestors, as well as nuts, roots, and tubers.

Predecessors to Homo sapiens ate and scavenged like Grok, a modern poster-boy for Paleo, eating a diet full of the meats and vegetables outlined previously. However, migrations out of the African peninsula caused novel foods to be introduced into the diet – including the grains and dairy commonly shunned by modern-day Paleo advocates (however, a 2015 study (11) suggests that the carbohydrates from starch may have been necessary to sustain Paleolithic life). Further, relocation into the Mediterranean presented foods like potatoes, bread, and olives into the human diet, and the consumption of milk began (12) upon the domestication of animals (around 9000 years ago).


Figure 1.  Human Fossil Sites from the Paleolithic Era. Different colored blocks represent fossil sites of different human species. Source: National Geographic Society 1988, 1997.

Recent advances in genetics have shown that while we share many genetic similarities with our ancestors, discrete genetic differences remain that differentiate modern humans from those who came before us, even those that were living only 15,000 years ago (13). Despite the continued assertions that Paleo is the optimal diet genetically suited for our bodies, the facts remain: our genes have changed significantly since the Paleolithic era and perhaps most significantly with regards to metabolism and digestion.

For instance, changes in diet over the last 10,000 years (14, 15) have lead to an increased consumption of dairy products, and suggest an adapted ability to digest lactose. Scientists have noted a strong correlation between lactase persistence (expression of lactase, the enzyme that breaks down lactose in humans), and the history of agriculture and dairy (16). Accordingly, lactase persistence is most common in northern Europe, Middle East, and North America and modern genetic data reveals that genetic markers associated with increased lactase gene expression are similarly prominent in populations with a history of herding cattle, and less common in many African populations.


Figure 2:  Prominence of a lactase persistence allele (A) of one genetic marker (rs4988235) associated with lactase. This data shows that African populations have a very low occurrence of carrying the genetics for properly metabolizing lactose in milk, while occurrence in Europeans is about 50/50. Source:

What does all of this mean?

There is no single way that our bodies are made to eat. Considering the vast genetic variation that has been documented since the introduction of the genus Homo, and the genetic differences currently existing between human populations today, it’s reasonable to assume that all humans metabolize foods differently.

In today’s era of personalized genomics, it is possible to uncover your personal genetic profile with Athletigen, and use this to directly inform a diet and exercise program designed to complement exactly the way your body has been made.

*The Paleo Diet is a registered trademark ® owned by Paleo Diet Enterprises LLC.


  1. Cordain, L. (2002). The Paleo Diet. John Wiley & Sons. 
  2. Aubrey, A. (2015, January 6). From Paleo To Plant-Based, New Report Ranks Top Diets Of 2015. NPR. Retrieved from
  3. Katz, D. L., & Meller, S. (2014). Can we say what diet is best for health? Annual Review of Public Health, 35, 83–103. doi:10.1146/ annurev-publhealth-032013-182351
  4. Mooney, K. (2014, July 24). Why NYC men are falling (rock) hard for the Paleo diet. Observer. Retrieved
  5. Westes. (2013, December 2). After two years on Paleo diet my cholesterol numbers look very bad [forum post]. Retrieved from
  6. Warmflash, D. (2015, April 15). Nutrigenomics: Can diets be tailored to an individual’s genetic make-up? Genetic Literacy Project. Retrieved from
  7. Corella, D., Peloso, G., Arnett, D. K., Demissie, S., Cupples, L. A., Tucker, K., … Ordovas, J. M. (2009). APOA2, dietary fat, and body mass index: replication of a gene-diet interaction in 3 independent populations. Archives of Internal Medicine, 169(20), 1897 1906. doi:10.1001/archinternmed.2009.343.
  8. Corella, D., Tai, E. S., Sorlí, J. V., Chew, S. K., Coltell, O., Sotos-Prieto, M., … Ordovas, J. M. (2011). Association between the APOA2 promoter polymorphism and body weight in Mediterranean and Asian populations: replication of a gene-saturated fat interaction. International Journal of Obesity (2005), 35(5), 666–675. doi:10.1038/ijo.2010.187
  9. Smith, C. E., Tucker, K. L., Arnett, D. K., Noel, S. E., Corella, D., Borecki, I. B., … Ordovás, J. M. (2013). Apolipoprotein A2 polymorphism interacts with intakes of dairy foods to influence body weight in 2 U.S. populations. The Journal of Nutrition, 143(12), 1865–1871. doi:10.3945/ jn.113.179051
  10. Zuk, M. (2013). Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live. W. W. Norton & Company.
  11. Hardy, K., Brand-Miller, J., Brown, K. D., Thomas, M. G., Copeland, L. (2015). The Importance of Dietary Carbohydrate in Human Evolution. The Quarterly Review of Biology. 90(3), 251-268. doi:10.1086/682587
  12. Bellwood, P. (2004). First farmers: The origins of agricultural societies. Wiley.
  13. Wade, N. (2006, March 6). Still evolving, human genes tell new story. New York Times. Retrieved
  14. Sun, J. X., Helgason, A., Masson, G., Ebenesersdóttir, S. S., Li, H., Mallick, S., Gnerre, S., Patterson, N., Kong, A., Reich, D., Stefansson, K. (2012). A direct characterization of human mutation based on microsatellites. Nature, 44, 1161- 1165, doi:10.1038/ng.2398.
  15. Turchin, M. C., Chiang, C. W., Palmer, C. D., Sankararaman, S., Reich, D., & Hirschhorn, J. N. (2012). Evidence of widespread selection on standing variation in Europe at height-associated SNPs. Nat Genet, 44(9), 1015–1019. doi:10.1038/ng.2368
  16. Lachance, J., & Tishkoff, S. A. (2013). Population Genomics of Human Adaptation. Annual Review of Ecology, Evolution, and Systematics, 44, 123–143. doi:10.1146/annurev-ecolsys-110512-135833

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