The History of Human Lifespan

Reevaluating the life expectancy of early humans compared to today

With modern advances in medical technology, both in the detection and treatment of diseases, greater access to healthcare, the eradication of many life-threatening illnesses, a wider variety of drugs and antibiotics, and the wide availability of food, clean water, and better sanitation practices, most people living in developed countries can expect to live a long life. 

While modern humans’ life expectancy is possibly longer than that of our ancestors, the question is whether modern man’s life is healthier than they were.

Life Expectancy Today

According to the CDC, as of 2020, the average life expectancy for Americans was 77.3 years (men: 73.9; women: 80.2). A chart shared by the CDC shows life expectancy has risen during the last 120 years. In 1900, life expectancy was around 50 years old. While there have been declines in life expectancy during this time, the overall trend is upward. 

Remember this is an average, and infant mortality is thought to factor heavily into that. 

Modern man has an advantage over his prehistoric ancestors helping mother and baby survive childbirth and helping children survive to adulthood. Average life expectancy is often discussed in terms of how old someone can expect to live, but that’s not really what this statistic is revealing.

Ancient Life Expectancy Controversy

It is a common notion that prehistoric humans lived much shorter lives than modern humans. However, according to a 1999 paper published by the Society for American Archaeology, this may not be true because of current methods of dating, specifically skeletal and dental age indicators. The authors note several examples of widely held beliefs about the average lifespan of ancient humans. 

Archaeologists sometimes theorize life expectancies as low as 15 years of age. The authors contend this is problematic, especially in cases where available historical documentation contradicts such low life span rates, stating that “it is rare to be able to validate age at death estimates on archaeological populations.” 

In cases of blind testing using the method of skeletal and dental age indicators, where the age of death was known by recorded evidence, it was found that there was a tendency to underestimate the age of older individuals. 

While there is no way to be certain of the life span of man’s prehistoric ancestors, to assume early man died much younger than modern man is a fallacy based on the preconceived notion that because our ancestors did not have our modern conveniences and advantages, they must have died younger.

Prehistoric Health Indicators

Along with the assumption that early humans died much younger than modern humans, it is also assumed that our ancestors suffered from poorer health. Yet, evidence indicates this was not the case. 

In his book Protein Power, Dr. Michael Eades points to records of fossil remains that indicate preagricultural prehistoric humans were “tall, lean, had well-developed, strong, dense bones, sound teeth with minimal if any, decay, and little evidence of severe disease”. 

With a diet primarily consisting of meat and fat, prehistoric humans were evidently strong, had good overall health, and were not plagued with the diseases of modern man. 

This is further supported by evidence from a 2002 meta-analysis published in the European Journal of Clinical Nutrition. To understand the possible impact of prehistoric man’s diet on health, researchers analyzed studies conducted on the dietary habits of contemporary hunter-gatherer societies, such as the !Kung people in Africa, the Eskimoes in Greenland, and the Nunamiut in Alaska, all of whom continue to eat their traditional diets and haven’t adopted more Westernized diets. 

The meta-analysis results revealed that, despite consuming higher quantities of protein and fat and very low quantities of carbohydrates, all studies analyzed indicated contemporary hunter-gatherers “have been shown to be relatively free of the signs and symptoms of CVD (cardiovascular disease).” 

The Rise of Agriculture and the Decline of Health

It is estimated that the dawn of agriculture occurred approximately 12,000-10,000 years ago, and evidence indicates that the rise in agriculture has led to a decline in overall human health. A 1995 study review published in Geography discusses the biological changes in humans due to the rise of agriculture. 

The paper states that domesticated plants, such as maize/corn, “leave detectable chemical and isotopic signatures in human remains,” allowing researchers to document the “shift to agriculture in various human populations.” 

Biological anthropologists have found a decline in dental health, with increased dental caries (tooth decay) and a decrease in tooth size, indicating a high consumption of nutritionally poor food. Growth rates declined. 

For example, anthropologists analyzing the juvenile long bones from prehistoric North America found evidence of “growth retardation in agricultural and mixed-subsistence economies.” 

Anthropologists have also discovered that the thickness of human bones decreased over time as agriculture became more prevalent. As humans became more dependent on crops, fossil records show evidence of anemia, as indicated by the presence of “sieve-like cranial lesions in the eye orbits.”

More “recent” evidence suggests the negative impact of agriculture on overall human health. As explained in Protein Power, the remains of mummified Egyptians provide insights into the health of a primarily agricultural population. 

Ancient Egyptian written records show their diet to be heavy in grains, particularly wheat and barley. They cultivated a wide variety of fruits and vegetables and used honey. They ate some fish and poultry, but very little red meat. 

While this diet sounds healthy by modern standards, the results were anything but healthy. Paleopathologists studying the mummified remains found evidence of gum disease, obesity, and advanced heart disease. Dissection of the arteries revealed calcified “cholesterol-laden deposits…exhibiting an advanced stage of atherosclerosis.”

Learning from History

While modern man may have evolved in terms of medical, scientific, and technological advances, our current health indicates we have also de-evolved as we’ve moved away from an ancestral and species-specific diet of meat and fat and embraced a diet heavy in grains, fruits, vegetables, and processed foods.

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