The evolution of the human diet

Noel-Garvan-column-image

The human diet has changed quite dramatically throughout our history. From opportunistic scavengers, to traditional hunter-gatherers to the postindustrial age.

There have been obvious advantages with the evolution of modern society, however the majority of changes in the human diet that accompanied both the Agricultural and Industrial Revolutions, affected the general health of modern humans, and not always in a good way.

Let’s have a look.

The Paleolithic era (2.6 million years ago – 10,000 years ago)
As hunter-gatherers, the general diet was varied due to differences in geographical location and season, however they all consisted of wild animal and plant sources.

Macronutrient distribution was approximately:

  • Protein: 19-35%
  • Fat: 28-58%
  • Carbohydrate: 22-40%

Other characteristics of hunter-gatherer diets included:

  • Low glycemic load;
  • High antioxidant capacity;
  • High micronutrient density;
  • Equal Omega-3 to Omega-6 ratio;
  • Close to equal Sodium to Potassium ratio.

Did hunter-gatherers eat grains and grasses? Probably. Did they eat them often? Unlikely. The effort required to consume unprepared grains or grasses would have been too taxing on the digestive system, which would have likely led to decreased performance and not enough of an energy return to warrant regular consumption.

As a result, hunter-gatherers were generally lean and strong, with dense bones and broad dental arches. Health biomarkers such as blood pressure and cholesterol were generally normal into advanced age.

Evidence suggests that the incidence of diet related disease was low.

The Agricultural Revolution (about 10,000 to 12,000 years ago)
Archaeological data indicates that the domestication of various types of plants and animals started happening in separate locations worldwide around 12,000 years ago.

The transition from a lifestyle of hunting and gathering to one of agriculture and settlement, made larger populations possible. This however, greatly narrowed the diversity of foods available, resulting in a downturn in human nutrition.

Grains and dairy products from sheep started to become dietary staples at the expense of larger wild animals.

As a result, common characteristics of early agricultural diets, compared to hunter-gatherer diets included:

  • Higher carbohydrate, diary fats, milk sugars and alcohol;
  • A decrease in protein intake;
  • A decrease in Omega-3
  • A decrease in antioxidants and micronutrients;
  • Higher overall caloric density;
  • Higher glycemic loading;
  • Higher sodium to potassium ratios.

The transition to an agricultural dietary pattern led to a decrease in lifespan, a reduction in height, an increase in dental health problems, iron deficiency anemia, and several bone mineral disorders.

These health issues can be still seen today in hunter-gather communities that have only recently been exposed to post-agricultural diets.

The Industrial Revolution (about 250 years ago) and Modern era (the last 50 years)
The introduction of novel foods with the industrial revolution altered several nutritional characteristics of human diets, which has had far-reaching adverse effects on human health.

Extensive evidence shows that the consumption of westernized modern era diets adversely affects gene expression, immunity, gut microbiota and increases the risks of developing cancer, heart disease, obesity, type-2 diabetes, and a plethora of other chronic health conditions.

Common characteristics of industrial and modern era diets, compared to hunter-gatherer diets include:

  • Higher carbohydrate, alcohol, trans-fats, sodium & omega-6;
  • Lower in fiber, antioxidants, protein and omega-3;
  • Higher glycemic load;
  • Higher energy density;
  • Lower micronutrient density;
  • Higher sodium to potassium ratio.

Even with the advances in medicine and technology, it has been estimated that the next generation will be the first in over one thousand years to actually have a shorter lifespan average than the current generation.

Many of the diet related diseases of the modern era can be reversed by increasing daily physical activity and modifying diet by eliminating known inflammatory foods. The issue however, is figuring out how to implement these changes at population-wide levels.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s