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Stress: Modern Lifestyle Factors in Opposition to Human Evolution

By Kyle Cordain, B.A.
December 19, 2016
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Rapid technological advancement and the demand for a faster paced lifestyle within our society has manifested stressors that our bodies are unfamiliar with. Put simply, “Our Stone Age brains just weren’t designed to handle the sedentary, isolated, indoor, sleep-deprived, fast-food laden, stressed-out pace of 21st-century life”.1

There are few studies on psychiatric disorders and stress among modern hunter-gatherers. However, an indigenous population known as the Kaluli of the highlands of Papua New Guinea follows a diet and lifestyle that is comparable to that of hunter-gatherer populations.2 Their population was observed to be virtually free of most of the common mental illnesses afflicting modern western society.3 Perhaps research on stress and mental health in hunter-gatherer groups is limited because it is so rare in the first place.

So, what exactly is to blame for the rapid rise of stress-induced mental pathologies in modern western society? Not every factor can be listed due to the vast array of stress inducing variables in western society, but here are a three factors in that are in strong opposition to our pre-agricultural hunter-gatherer way of life:


The food you eat is the foundation of any success you’ll experience in improving your overall physical and mental well-being. Most westerners follow an inflammatory diet far removed from our evolutionary past that is centered on the consumption of grains, omega-6-rich foods, artificial sweeteners, dairy, and other low-nutrient density foods.

This is a sure recipe for disaster for those seeking mental clarity. Instead focus on eating an anti-inflammatory ancestrally-based Paleo diet that includes pasture-raised non-dairy animal products, fresh fruits and vegetables, nuts, seeds, and either animal tallow, olive oil, or coconut oil for cooking.

One of the best nutrients you can consume on a regular basis for superb mental health is a PUFA (polyunsaturated fatty acid) known as omega-3 fatty acid. The fact alone that one out of every three fatty acids in the human central nervous system is comprised of PUFA should be enough to convince you how important omega-3 fatty acids are for your brain’s health.4 Furthermore, cross-cultural studies on rates of depression5, bipolar disorder6, and seasonal affective disorder7 were demonstrated to be lowest in countries consuming diets rich in omega-3 fatty acids from seafood. Omega-3 fatty acids are also critical in the production of the mood and motivation associated brain neurotransmitters serotonin and dopamine.1 Salmon, mackerel, sardines, oysters, cod, herring, shrimp and wild or pasture raised meat and eggs are all great sources of omega-3 fatty acids.

Sedentary Lifestyle

A sedentary lifestyle tends to go hand-in-hand with isolation. More screen time usually means more time on the couch or office chair. Frequent exercise and taking up an occupation that does not require long periods of sitting are ideal for combating this issue. It is widely known that exercising causes the brain to release endogenous opioids known as endorphins which can be helpful in alleviating stress-related disorders such as anxiety and depression.8 Conversely, too much exercise can have negative effects on mental well-being.9 Seeking balance is key.

Circadian Rhythm

Circadian rhythms are an often-undervalued component of good health that is largely ignored in modern society. Put simply, your circadian rhythm is all the physiological processes that happen within your body in a span of 24 hours.10 Your body’s circadian rhythm is dictated by factors such as sunlight and temperature.

The sun’s influence alone causes the body to produce both the stress hormone cortisol and the sleep hormone melatonin to maintain equilibrium in bodily functions throughout the different seasons. In the summer, cortisol is high and melatonin is low. In the winter, the inverse is observed.11

Modern technology now allows for light 24/7 regardless of the season or time of day in just about every person’s home. Instead of having higher levels of melatonin flood our brains upon nightfall, the abundance of indoor lighting effectively suppresses melatonin and tricks our brains into thinking that it is still day time well after the sun has set. Blue light is particularly effective at suppressing melatonin and the highest emissions are from computer displays and televisions.

The end result is high levels of the stress hormone cortisol circulating through one’s body constantly. Year-round suppression of melatonin and heightened cortisol can contribute to chronic stress, inflammation, and mental health issues related to sleep deprivation that can go on endlessly.12

It’s worth noting that blue light is not inherently bad and is actually needed during the daytime to ensure alertness, productivity, and adequate Vitamin D3 (very important) uptake. It’s when blue light is delivered in the evening and late night hours that it becomes problematic.13 After sunset it’s best to avoid late night television binges or close contact with computer screens to avoid high cortisol upon hitting the sack for the night. There are plenty of other activities such as reading a book, listening to music, socializing, meditation, etc. that do not entail exposure to blue light. Choose light bulbs for your house that are rated at 2700 degrees Kelvin or less. Also, consider installing “f.lux” for your home computer to lessen the blue light exposure coming from your computer screen if you must use your computer into the night.

Final Note

It’s wrong to think that hunter-gatherers lived a completely stress-free life. Stress is a necessary for natural selection pressures and is likely what guided the selective forces that shaped humankind. But the type of stress that hunter-gatherers underwent was likely a very different kind of stress than what is observed in modern society. Instead, stress and the release of cortisol was likely an episodic response to periodic events such as food shortages, predators, and confrontation with neighboring clans.

Nowadays, the innate complexity of modern society tends to create a psychological functioning that lends towards chronic low-grade stress as an adaptation mechanism to deal with the ever-increasing multifaceted demands of western existence.14

It is next to impossible to completely emulate the lifestyle of a hunter-gatherer if you are a citizen of western society as a solution to stress and overall health. That being said, you can certainly question many of the cultural attributes that are taken for granted in modern life in relation to our hunter-gatherer past and seek solutions that fit your personal circumstances. Building a lifestyle that is centered upon healthy eating and emphasizes stress relief instead of chronic stress is essential for keeping inflammation low and mortality high.


[1] Ilardi, S. S. (2009). The depression cure: The 6-step program to beat depression without drugs. Cambridge, MA: Da Capo Lifelong.

[2] Feld, Steven (1982). Sound and Sentiment: Birds, Weeping, Poetics, and Song in Kaluli Expression. Philadelphia: University of Pennsylvania Press. pp. 4–5.

[3] McErlean, B. (2015). Soundness in mind and body. Veterinary Record, 177(23), i-ii.

[4] Logan, A. C. (2004). Omega-3 fatty acids and major depression: a primer for the mental health professional. Lipids in health and disease, 3(1), 1.

[5] Hibbeln, J. R. (2002). Seafood consumption, the DHA content of mothers’ milk and prevalence rates of postpartum depression: a cross-national, ecological analysis. Journal of affective disorders, 69(1), 15-29.

[6] Noaghiul, S., & Hibbeln, J. R. (2003). Cross-national comparisons of seafood consumption and rates of bipolar disorders. American Journal of Psychiatry, 160(12), 2222-2227.

[7] Cott, J., & Hibbeln, J. R. (2001). Lack of seasonal mood change in Icelanders. American Journal of Psychiatry, 158(2), 328-328.

[8] Peluso, M. A. M., & Andrade, L. H. S. G. D. (2005). Physical activity and mental health: the association between exercise and mood. Clinics, 60(1), 61-70.

[9] Pierce, E. F. (1994). Exercise dependence syndrome in runners. Sports Medicine, 18(3), 149-155.

[10] Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001. The Circadian Cycle of Sleep and Wakefulness. Available from:

[11] Wiley, T. S., & Formby, B. (2000). Lights out: Sleep, sugar, and survival. New York: Pocket Books.

[12] Quera Salva, M., Hartley, S., Barbot, F., C Alvarez, J., Lofaso, F., & Guilleminault, C. (2011). Circadian rhythms, melatonin and depression. Current pharmaceutical design, 17(15), 1459-1470.

[13] Münch, M., Linhart, F., Borisuit, A., Jaeggi, S. M., & Scartezzini, J. L. (2012). Effects of prior light exposure on early evening performance, subjective sleepiness, and hormonal secretion. Behavioral neuroscience, 126(1), 196.

[14] Sapolsky, R. M. (1994). Why zebras don't get ulcers: A guide to stress, stress related diseases, and coping. New York: W.H. Freeman.

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