Hominins, that is, bipedal primates, have existed and evolved for at least 5-7 million years now. Throughout this long-time scale, Darwin’s theory of Natural Selection was well at work. It shaped and adapted hominins bodily system in accordance with many environmental factors. Here, I will focus on food.
There was no single universal diet consumed by all extinct species. Diets varied by geographic locale, climate, and specific ecological niche. However, there are some universal characteristics of pre-agricultural diets that are very useful in understanding how the current Western diet may pre-dispose modern population to chronic diseases such as obesity, high blood pressure, high cholesterol, cardiovascular diseases, diabetes, and osteoporosis.
We, current humans, Homo Sapien Sapiens, have evolved from previous hominins through millions of years. Agriculture and domestication of animals have only very recently appeared on this large time-scale: about 10 000 years ago. Before that, humans were hunter-gatherers. When comparing diets of pre- and post-agriculture, it’s important to not only look at the nutrients and types of food that people ate, but also what they did not eat (and that we do eat now).
Dairy products, refined sugars, cereals, refined vegetable oils, and alcohol make up 72.1% of the total energy consumed by the average American in the year 2000. These foods would contribute none to very little energy in past diets. It means that our bodies are not made to consuming them now, especially in the quantity that we are, and thus result in chronic illnesses or diseases.
Dairy Foods
Hominins, like all mammals, drank the milk from their own species as infants, and then stopped after the suckling period. The consumption of other animals would have been nearly impossible before domestication; it is quite difficult to capture and milk a wild animal. Moreover, even though sheep, goats, and cows were domesticated around 10 000 years ago, early direct chemical evidence for dairy dates to 6100 to 5500 BP. That is to say, on an evolutionary timescale, dairy is quite a newcomer.
Cereals
Because wild grains and cereals are small, difficult to harvest, and require processing prior to consumption in order to be digestible, we can rely on the appearance of tools such as ground stone mortar in the archeological artefacts to find when humans first started to eat cereals. They first appear in the Paleolithic period (40 000 to 12 000 years ago). However, the regular exploitation of grains by any world-wide hunter-gatherer group emerged in the Latufian culture in the Levant (close to today’s Turkey), about 11-10 000 years ago. Therefore, prior to that period, there was little to no previous evolutionary experience for cereal grain consumption throughout the hominin evolution. Now, in the Western diet and especially in the US, there is a very high intake of cereal that is highly processed. The cereal significantly loses its nutritional characteristics through this processing (used in cookies, cake, bakery goods, bagels, rolls, muffins, crackers, etc.). This is a recent phenomenon – about 150 to 200 years.
Refined sugars
The western world has seen a steep increase of refined sugar since the Industrial Revolution some 200 years ago.
The very first evidence of crystalline sucrose production appears about 500 BC in northern India. Before that, honey would have been one of the few concentrated sugars to which hominins had access to. Although honey was accessible to nearly all hominins, the seasonal availability would restrict its access. It represented only a minor dietary component over the course of a year, even for the groups of hominins that used honey in high intakes on small periods. The current intake of sugar had no precedents during hominin evolution. The introduction of the food processing industry introduced very high quantities of refined sugar into our diets.
Refined vegetable oils
In the US from 1909 to 1999, a striking increase in the use of vegetable oil occurred. Cooking oils have increased by 130%, shortening by 136%, and margarine by 410%! Oils made from walnuts, almonds, olives, sesame and flax were first produced around 5000 to 6000 ago, however, they were used for nonfood purposes like illumination, lubrication, and medicine. With the new manufacturing procedures and the industrialization of the food, oil is being added to a great quantity of processed foods. Moreover, a new process – hydrogenation – gives the oils an atypical structural characteristic, which creates trans-fat. Trans-fat rarely, if ever, occurrs in conventional human foods. This adding of vegetable oil to the world’s food supply significantly altered quantitatively and qualitatively our fat intake.
Alcohol
Wine was first found in the years 7400-7100 before present in northern Iran, and beer about 4000 before Christ in southern Iran. The incorporation of distilled alcohol came much later, around 800-1300 AD in Europe, Near East, and China. Prior to that, fermentation would happen in nature all the time, but it was not controlled and stored as it is now. It’s likely hominins had a very insignificant to non-existent amount of alcohol in their diet.
Salt
The earliest use of salt is argued to have taken place in northern China, in the province of Shanxi, by 6000 BC, and in Europe in Spain in 6200-5600 BP. Some hominins of the Paleolithic period up to today (2.6 million years ago) did probably dip food in seawater or used dried seawater salt, however it was not all groups and it was not in the quantity that we are now consuming. Currently, we are having a very high salt intake from our processed food, 90% of which is added to the food (75% is added from processed manufactured food and about 15% is added from discretionary source like table salt use). Only about 10% of the salt we consume comes from the actual natural food.
Conclusion
In the US, diet-related chronic disease represents the single largest cause of morbidity and mortality. The ultimate factor underlying diseases of our civilization is the collision between our ancient genome with the nutritional qualities of our recently introduced foods.
