Is There a Universal Healthiest Diet for Humans?
Is there a universal healthiest diet for humans?
This is one of the biggest questions of our time! With the explosion of nutritionists, health coaches, and functional medicine practitioners, you can find virtually any opinion on nutrition out there. Some people argue for balance and moderation in all things, even when it comes to processed and “junk” foods. Other people espouse a plant based, low fat, high in vegetables and whole grains type of diet. Still others argue for a high fat, low carbohydrate, meat heavy diet. And everything in between and to the extremes is argued for as well, from “Mediterranean” to raw fruitarian to full carnivore. Can we ever distill these myriads of opinions into a clear, coherent answer on the truly healthiest human diet?
Unfortunately, probably not- simply because nutrition is notoriously difficult to study. There are simply too many variables to account for- and truly controlled studies where people live in wards and have all their food prepared for them are too expensive to do long term. Most nutritional studies are epidemiological, meaning they are using self report forms in large populations and looking for correlations. Many questions arise in these kinds of studies: are people reporting correctly? Which foods are truly responsible for the correlations being seen? Are lifestyle factors being appropriately accounted for? Does the quality of the food have an impact, and how much? You can see how conclusions drawn from epidemiological studies are questionable at best.
With very few long term interventional studies available and many problems with epidemiological studies, we are left with individual anecdotes and patterns of ancestral diets and the history of increasing chronic health conditions. While neither of these lives up to standards of scientific rigor, they can give us important information nonetheless.
The first factor is that individuals need to be trusted to know the experiences of their own bodies. People who have made dramatic mental and physical health improvements on extreme diets exist- I am one of them. The problem is that people make these seemingly miraculous recoveries on a myriad of different dietary protocols. I healed from my severe autoimmunity using a meat based diet of traditional soups- while an online acquaintance of mine healed from the same severe condition eating a diet of mostly raw tropical fruits. Even if they seem at odds, the undeniable truth of our own experiences exist.
While anecdotal stories of nutritional healing are numerous, fascinating and inspiring, they do not necessarily help with our question, as there will be as many answers experienced as there are people. Our last avenue is to assess patterns of ancestral diets, human evolution, and the historical origins of chronic disease. This line of inquiry leaves us with similar problems as epidemiological: mainly, that there are simply too many variables to accurately track. However with a sample size of the earth and all of history, we can piece together some insightful patterns.
Who are the Healthiest Humans and What do they Eat? Overall Patterns
Numerous studies have shown that people living traditional lifestyles away from contemporary processed food have much lower rates of chronic disease including heart disease, cancer, asthma, allergies, and autoimmunity. In fact, in many traditional communities, these conditions are virtually unheard of. This fact was first documented by the doctor Weston A. Price, who traveled the world in the 1930’s documenting the diets of traditional people and the shifts in their health markers once they began eating processed Westernized food. His findings were striking. Within one generation, chronic disease and other markers of ill health increased. Additionally, more recent observation of indigenous communities introduced to modern processed diets show similar changes over the generations. This work has shown inarguably that a modern, processed food diet increases rates of chronic disease (Kopp, 2019).
A universal conclusion can be drawn from this: all humans, no matter where they are from or what their culture is, experience more chronic disease with the introduction of processed foods. A whole foods diet of minimally processed food is probably one of the most effective ways to promote good health. We can then conclude that a whole foods, minimally processed diet is the universal healthiest diet for humans.
But can we get any more detail than that?
Dr. Price, as well as more contemporary anthropologists have observed other patterns as well. All traditional diets documented consumed at least some of the following foods: Saturated fat from animals, organ meats from animals, some amount of both raw and cooked food, some type of fermented foods (either vegetables or meats), some amount of “properly prepared” plant foods, some consumption of bones (either raw marrow or in broths), and unrefined mineral salts. This makes sense, as there are important fat soluble vitamins, amino acids, and other nutrients that can only be obtained in reasonable amounts from animal foods. Probiotics and minerals are also important to human health which explains the reliance of ferments, mineral salts and bones. The rest seems to vary considerably from tradition to tradition, mainly in the ratio of plant to animal foods or carbohydrate to saturated fat based foods consumed. Some cultures ate over 90% carnivore, while others had a much lower percentage of total calories coming from animal sources (30% was the lowest that Dr. Price documented) and a higher percentage coming from plant sources.
If we are still assuming that principles of traditional diets can be used to prevent chronic disease and promote overall health and wellbeing, this does not give us any one clear dietary pattern. It appears that being both high fat and more “meat based” and lower fat and more “plant based” can both promote optimal health. What we can summarize from his findings is that some consumption of animal foods, especially the fat, organ meats, and bones, is essential to good health. Fermented foods, unrefined salt, and some amount of properly prepared plant foods seem to also be important components of a “healthy human” diet. Beyond that, there is great variability.
Balance of Nutrients and Anti Nutrients
All food consumption is a balance of nutrient and anti nutrients, and this is true for all animals. For example, in his book “100 Million Years of Food”, Stephen Le describes how squirrels eat the top of acorns and leave the bottom because there are more toxic compounds (specifically tannins) at the bottom of the acorn. All organisms have defense mechanisms that must be dealt with in order to be eaten: animals have claws, venom, and movement mechanisms to get away from predators. Plants have spikes and toxins. Eating requires neutralizing these defense mechanisms in order to receive the available nutrition. With animals, this looks like hunting or harvesting the animal, and butchering it in a way that removes any sharp or venomous parts. For plants, this looks like “proper preparation”.
Traditionally, very few plants are eaten raw. They are extensively and intentionally prepared through grinding, smashing, soaking, boiling, sprouting, fermenting, and many other ancient processes. Unfortunately, a convenience oriented lifestyle plus our cultural obsession with high vegetable intake has increased our exposure to not only the artificial toxins of processed food and food additives but also natural toxins found in plants.
A universal healthy human diet may or may not include high amounts of plant foods, as many traditional cultures exist in which the vast majority of their diet comes from animal sources. However, we cannot say that the universal healthy human diet mostly excludes plant foods either. Many traditional cultures eat the majority of the calories from plant sources and live without the burden of chronic disease. However, I would argue that a universal healthy human diet includes the proper preparation and respect for the consumption of plants. While many traditional cultures thrive on the consumption of high toxin plant foods such as corn, beans, and rice, they are prepared extensively and intentionally and eaten seasonally to avoid the possibility of toxic overload.
So far, a universally healthy human diet looks like: Whole foods, minimally processed, with some consumption of animal foods, ferments and mineral salts, and some amount of properly prepared plant foods.
Ancestry
Ancestry may be an important factor in determining where on the “meat based” to “plant based” scale you might optimally fall. So far, it appears that a healthy human diet can look a lot of different ways as long as it contains some amount of the foods we have already discussed. So why do some people seem to tolerate the carbohydrates and toxins found in plants much better than others? We can see from traditional cultures that carbohydrates themselves, though often maligned, are not the problem. In fact, many historically healthy cultures have thrived on quite high carbohydrate diets. Other people run into highly dysregulated metabolisms when they eat higher carbohydrate diets and find they thrive when they focus their diet around animal fats.
Although all humans are the same species, we have had many thousands of years to diversify and find our ecological niches. This means that at the level of metabolism, microbiome, and nutrient absorption, we do have differences related to our specific ancestry. In most general terms, this means that the closer your ancestors lived to the equator, the more likely they adapted to rely on plant foods. The farther they lived from the equator, the more likely they adapted to rely on animal foods. And in middle/temperate zones, seasonality of foods was most relevant (more plant foods in the summer and fall, more animal foods in the winter and spring).
In this way, we can argue that there is no universal healthy human diet beyond the parameters that have already been set. Instead, one must begin by looking at their own ancestry and from there self experiment to optimize their individualized healthiest diet.
Protein Intake: Maximizing Longevity Vs. Reproductive Optimization
Another issue is clearly defining what we mean when we say “health”? In “100 Million Years of Food”, Stephen Le describes how this can be defined two different ways: either maximizing longevity OR optimizing reproductive capacity. Both goals will show a decrease in chronic disease, but otherwise have significant differences. Indeed, many people have argued that a calorically restricted, low protein diet is the healthiest diet because studies have shown that it increases longevity. While this is true, it is in part because a low calorie and low protein diet minimizes reproductive potential, so cellular and metabolic processes are refocused on maintaining life until the opportunity for reproduction presents itself again.
Reproductive optimization is more of a state of thriving. It is when the body has excess energy and nutrients that can be passed down to offspring. This is a state of optimal health, but not necessarily longevity, as our cellular and metabolic processes will not prioritize longevity when we are in a state of reproductive optimization.
This means you can be malnourished, cranky, non fertile, eat very little protein, and live a very long time, OR you can be full of nutrients, energy, reproductive potential, eat a lot more protein, and not live as long. In both free instances as long as you are eating in terms of the parameters discussed you will likely be free from chronic disease. I know which life I would pick! My bias is that quality is more important that quantity, although each person will have to make that decision for themself.
When Are Restrictive Medical Diets Appropriate?
When looked at from an ancestral, multi cultural perspective, there are many ways to eat and minimize chronic disease. All traditional cultures have historically been healthy, happy, and fertile, even when eating in many different patterns. However, health is an intergenerational phenomenon, and traditional people generally started out in good health, born from parents and grandparents also in good health. What happens when we are born in a compromised state, and develop chronic disease at a young age, passed down from our parents and grandparents?
The general definition of a universal healthy human diet no longer applies in these cases. This is similar to the function of a vitamin deficiency and why supplements can be very important in correcting nutritional imbalances: food is excellent at maintaining nutrient levels, but once depleted, they are hard to get back from food alone. While maintaining health on a traditional diet of any kind is absolutely possible, regaining health is not always. There are certain medical diets that are appropriate short term (generally 6 months – 3 years) that are necessary to reset a dysfunctional metabolism, microbiome, and cellular health. After this, returning to any type of traditional diet long term is an excellent way to maintain that regained health.
In Summary
Chronic disease occurs where ever people are disconnected from their traditional dietary patterns, whether voluntarily or involuntarily. So if there is a universal healthiest diet for humans, it would be to follow an ancestral pattern of animal foods, ferments, mineral salts, bone soups, and some amount of properly prepared plant foods. Beyond that, self experimentation based on ancestry is necessary, and a structured medical diet may be essential to intervene in more serious health conditions.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6817492/
Weston A. Price “Nutrition and Physical Degeneration”
Stephen Le “100 Million Years of Food”
