The Evolution of Diet
How our environment has changed along with what and how we eat
by: Chris Maxey
Throughout most of human history, we’ve eaten what is available. Be it honey, fruit, leaves, stems, seeds, or anything else, we’ve consumed what nature provides. Energy-dense foods such as honey and meat were not as readily available to the degree they are today. Take a look at the modern supermarket. More space is given to shelf-stable, ultra-processed foods. A simple search on Walmart’s website confirms this trend.
The modern diet has changed drastically from what our ancestors ate. Researchers observed a hunter-gatherer tribe in Tanzania. This tribe, known as the Hadza, consumes 4-5 times more fiber than the average U.S. citizen. It’s not that they innately want to eat what is healthy. They’re simply eating what is available in their environment. Members of the Hadza will eat honey when it is available. In fact, honey accounts for about 15% of their energy consumption.
In our current environment, we’ve turned the natural order of dietary intake on its head. Processed foods contain more calories per gram and cost less per calorie compared to healthy foods. Heavily processed foods are available year-round and have a long shelf life. Foods that were previously uncommon are now more abundant than ever. Let’s look at a simple comparison between an apple and an Oreo. It takes about 2-4 weeks for an apple to decompose. Oreos can last 3-4 weeks longer than their printed date. In short, they’ll last for months longer than an apple.
The environment in which we live has a tremendous impact on our health. Even individuals who are genetically predisposed to chronic conditions can fare better if they change their environment to better align with the needs of their bodies.
Genetic predisposition is not a guarantee that one will suffer from an illness. It simply means that they must put forth more effort than others to prevent certain conditions. An example of how important the environment is on our health can be found in the Pima Indians. The Pima are descendants of the ancient Hohokam, who have inhabited the Sonoran desert and Sierra Madre regions for centuries. The Hohokam moved into the Gila River valley around 300 B.C., which was Mexican territory at that time. After the Gadsden Purchase of 1853, the United States acquired parts of northern Mexico. This caused further separation between the O'odham (residing in modern-day Arizona) and the Pima Bajo (residing in Maycoba, Mexico). In 1959 a Pima reservation in Arizona was created and the majority of Arizona Pima continue to reside there.
These two different groups of people, the Arizona Pima and Mexican Pima, with the same genetic makeup have much different health outcomes simply because of their environment. The Mexican Pima have a lifestyle that is more consistent with how their ancestors have always lived. The Arizona Pima lost their ability to continue subsistence farming following the diversion of water from the Gila River. They were then dependent on the U.S. Government for support. This support came in the form of free commodity foods such as white flour, cheese, refined sugar, lard, and canned foods.
How are we building our environment? Modern technology and genetic modification have made highly processed foods incredibly available for a fraction of the cost of unprocessed foods. Subsidized by the U.S. Government, the Supplemental Nutrition Assistance Program (SNAP) is designed to help people of lower socioeconomic status afford food. It may be a surprise to learn what foods can be bought with SNAP benefits. You can buy various processed foods with SNAP credits, and oftentimes SNAP users are attracted towards processed foods because they are cheaper compared to nutrient dense foods. At a significantly lower price, SNAP users are able to purchase more processed food items on a limited budget.
Conclusion
Energy-dense foods were not as available as nutrient-dense foods in the past. Because of many factors such as industrialization and U.S. Government subsidies, energy-dense foods are now more available than ever.
Our dietary patterns today are not inline with how humans have eaten before agriculture and industrialization.
Genetics can play a role in health outcomes. However, our environment (which includes our food) plays a much larger role.
If we observe groups of people who eat how they always have (like the Hadza in Tanzania), we see better health outcomes, higher fiber intake, and an absence of the chronic diseases that are prevalent in countries like the United States.