Human Diet Evolution: From Ancient Ancestors to Modern Health Challenges

Posted on Jun 27, 2025 in Medicine & Health

The Evolution of Human Diet: From Ancient Ancestors to Modern Health

“In the history of humanity, diet has been the strongest evolutionary factor.”
Initially, the human diet was based solely on fruit. Over time, humans began adding other plant foods such as roots and nuts, which promoted changes in human development, including the evolution of teeth and mastication mechanics.
Humans also developed cultural strategies, such as using stones to crack nuts and producing sharp stone tools to cut and serve food.

Upright posture facilitated adaptation to life under the sun’s rays, allowing hominids to cover greater distances at times when predators were asleep.
This led our ancestors to discover scavenging, gaining access to reserves of fat and protein contained in the marrow of the long bones of dead animals.
The consumption of these energy sources led to greater brain development.

In the Paleolithic period, the consumption of fish, small animals, and shellfish, as well as plant foods and fruits, was crucial to the evolutionary changes that shaped the genetic structure we inherited from our ancestors. This dietary pattern was called the Paleolithic diet.

With the advent of agriculture and livestock farming, the human diet drastically changed from what it had been until then.
The contribution of cereals to the diet reached up to 90% of food intake, with a very low intake of animal-derived proteins.
The greater efficiency of food production generated surpluses that led to profound demographic changes, the emergence of social classes, the development of bureaucracies, and ultimately, the development of cultural, food, and social technologies.

The imbalance of the diet in agrarian societies explains the emergence of diseases such as protein-energy malnutrition, reduced stature among their members, and the epidemic of chronic diseases we face today.

The most recent significant change in the human diet is a result of the Industrial Revolution.
Intensive agriculture and food technology have introduced foods that were largely absent during large stretches of hominid evolution: fats, refined sugars, and vegetable oils.

An increase in energy intake coupled with decreased energy expenditure.
An increase in saturated fat consumption and lower intake of omega-3 fatty acids.
A decrease in the consumption of fiber and complex carbohydrates.

“In terms of genetics, modern humans live in a nutritional environment that differs from that for which our genetic constitution was selected.”
This is a relatively short period—approximately 10,000 years—during which selective pressures have not been sufficient to produce new adaptive changes.
The contradiction between the modern diet and the genetic structure resulting from adaptation to the Paleolithic diet is known as “evolutionary dietary discordance.”
The current epidemics of diseases such as obesity, diabetes, hypertension, and dyslipidemia are direct results of this evolutionary discordance.

The ancestral human genetic structure prioritized metabolic processes that defended energy reserves in a lifestyle characterized by intense physical activity. This metabolic priority, however, is now mismatched with modern sedentary lifestyles.
Given that genetic modification seems out of reach, the alternative to modify the current epidemiological picture is to revert, in some ways, to a Paleolithic lifestyle. This includes:
- Increased consumption of fruits and vegetables.
- Increased consumption of polyunsaturated fats.
- Reduced fat intake overall.
- More physical exercise.