Contemporary foods and cultures inhibit our body’s inborn ability to select nourishing diets
We are told by the authors of diet books that our bodies evolved to eat a certain way. Depending on which scientific evidence they draw upon, the authors claim our ancestors were vegetarians, omnivores or carnivores. We are instructed that we now eat in a different way, which our bodies are not handling well. This is the basis for diets from Atkins to Zone and everything in between. Ironically, many of these diets are now cited by critics as reasons for our dietary diseases.
To add to the confusion, we are daily informed of the latest scientific findings, which often contradict previous findings. Supplement that with regular reminders of the global obesity crisis and the effects of what we eat on rising costs of human health, and one is hard pressed to argue that humans possess nutritional wisdom. Indeed, the Centers for Disease Control and Prevention (CDC) projects 70 percent of people in the United States today will die of diet-related diseases.
Is it any wonder that most scientists don’t believe humans have nutritional wisdom and that we must be told endlessly what and how to eat? But if modern humans don’t know what and what not to eat, that raises intriguing questions: Did hunter-gathers know which plants and animals to eat to obtain the nutrients and medicines they needed? How do wild animals know how to acquire the nutrients and medicines they need from the landscapes they inhabit? Is it true that modern humans can’t do what wild animals do without any advice from experts?
Not unlike with contemporary humans, most scientists don’t believe farm animals have the ability to self-select diets that meets needs for nutrients and medicines. They claim livestock lost those abilities as a result of domestication. Nevertheless, I spent my academic career questioning the prevailing notion that livestock are “too dumb” to make nutritionally sound choices.
My graduate students and I showed that cattle, sheep, and goats who are free to choose from suitably diverse assortments of forages still respond to an intricately tuned system of flavor-feedback relationships at the cellular level. This can guide them to meet their needs for both nutrients and medicines. In my new book Nourishment: What Animals Can Teach Us About Rediscovering Our Nutritional Wisdom, I extend the theories behind this research to human food selection, nutrition, and health.
Historically, people made a distinction between palatability (what a body likes to eat) and nutritional needs (what a body needs to thrive). We assumed humans and other animals like certain foods because they inherently taste good and dislike other foods because they taste bad. We did not consider that our bodies would perceive foods as tasting good when they meet the needs of cells and organ systems, including the microbiome, and as tasting bad when they do not.
An attuned palate, which enables animals to meet needs for nutrients and to self-medicate to rectify maladies, evolves from three interrelated processes: flavor-feedback associations; learning to select appropriately from foods that contain energy, protein, minerals and vitamins, as well as a host of other compounds—including but not limited to phenolics, terpenes and alkaloids—with nutritional and medicinal benefits; and learning in utero and early in life to eat combinations of foods that meet needs for nutrients and medicines.
Bodies are societies of cells and organ systems, each with nutritional needs unique to the “ecosystem” they inhabit. What I call “myself” is a conduit through which the trillions of cells that make up the organs that comprise “my body” meet their nutritional needs. Each cell, with thousands of receptors in its membrane, can use only nutrients its host provides. Flavor-feedback associations enable cells and organ systems to influence which foods the host selects. Feedback changes liking for foods as a function of needs. And that takes place without a bit of thought.
The non-cognitive facets of flavor-feedback relationships are akin to the not-thinking we don’t do as our bodies release the many enzymes required to digest and assimilate the foods we eat. In fact, thoughts can interfere with these processes. For instance, many people who aren’t sensitive to gluten think they are so, due to constant warnings about its harmful effects. As a result, they get sick when they are told food they eat contains gluten, even when the food doesn’t contain gluten. This food hexing, which has occurred for eggs, full-fat meat and dairy products—and some contend is now happening with foods high in refined carbohydrates—is not unprecedented.
Not unlike wild animals and farm animals that are locally adapted to the environments they inhabit, our hunter-gatherer ancestors evolved cultures that ate locally available plants and animals in a time-proven manner that ensured survival through cycles of abundance and scarcity. In this process, palates linked their cultures to landscapes through experiences that began in the womb, as the flavors of foods mother ate were transferred into her amniotic fluid and savored by her fetus. Offspring continued to learn about mother’s diet through flavors of foods transferred in her milk. As they began to forage for themselves, the young learned by watching mother and peers.
Nowadays, unfortunately, manufactured foods in supermarkets and the choices people learn to make are under the influence of “elders” in academic, corporate and political institutions. While not always the case, these organizations routinely inhibit discourse, shape and skew the scientific literature, manufacture and magnify public uncertainty, and influence government policies to advance dangerous “food” products. Their influence in marketing manufactured food products has enabled some in science, industry and politics to influence the masses and reap the profits.
We’ve come to trust these “authorities” for advice. Ironically, the more scientists and medical doctors have come to appreciate the countless intricacies of food selection, nutrition and health, the less people have reflected on the wisdom of the body as the source of this complexity.
In the process, we fail to consider a crucial point, one the body of every wild insect, bird, fish and mammal who ever roamed the planet “comprehends” from experience: the body was the first geneticist, molecular biologist, physiologist, nutritionist, pharmacist and physician. A healthy body knows how to eat a nutritious diet, given wholesome choices and proper social models.
Appreciating this simple insight could change dietary advice—from an endless stream of recommendations on what and what not to eat—to creating cultures that know how to grow and combine wholesome foods into meals that nourish and satiate.
Unfortunately, it’s not that simple. Farming practices—irrigating and applying fertilizers to stimulate growth at the expense of phytochemical richness—along with genetic selection for yield, appearance and transportability diminish the flavor, phytochemical richness and nutritive value of fruits and vegetables. Phytochemically impoverished pasture and feedlot diets adversely affect the health of livestock and the flavor and biochemical richness of meat and dairy products.
The phytochemicals that wild plants contain limit how much of a plant species any animal can eat. To meet needs for nutrients and avoid toxicity, animals must eat small amounts of a variety of different plants, each with dissimilar phytochemicals that can be detoxified in different ways. In turn, eating small amounts of a diverse array of phytochemicals exposes cells and organ systems to a wide array of compounds, which at low doses, have significant health benefits.
Ironically, as the flavor and nutritive value of produce, meat and dairy humans eat became blander, processed foods became more desirable. People in the food industry learned to link feedback from energy-rich compounds with artificial flavors that obscure nutritional sameness and diminish health. Thus, the roles plants and herbivores once played in nutrition and health have been usurped by processed foods fortified and enriched in ways that adversely affect appetitive states and food preferences, with the result that we avoid eating wholesome foods.
The need to enrich and fortify processed foods, along with our penchant to take supplements, can be eliminated either by sourcing meat, dairy and produce from people who produce biochemically rich foods or by growing those foods ourselves. One family at a time, we can also create cultures that know how to combine wholesome foods into meals that nourish and satiate.
This blog post by Fred Provenza first appeared in Scientific American.