Updated: Nov 14, 2019
This post is the first in a series that will cover my Five Health Essentials: diet, fitness, stress management, nurturing and supportive relationships, and spiritual realization. These are the ingredients that synergistically create and maintain a healthy lifestyle.
The best human diet is a high protein, low carb diet. No, wait, the best human diet is a high carb, low protein, low fat diet. Maybe it’s a high fat, moderate protein, low carb diet that works best.
You’ve probably heard of them all by now: keto, paleo, vegan, vegetarian, plant based, Atkins, traditional, Mediterranean, flexitarian, etc. etc.
But which one is best?
Before we can decide which diet is best for us, it will help to explore three areas:
1. The context in which human dietary needs evolved and remain paramount today.
2. How a mismatch between the modern industrialized diet and our evolutionary dietary needs is at the core of the current epidemic of chronic diseases, including weight gain.
3. Exploring which diet(s) come closest to meeting our ancestral nutritional requirements.
Evolution (Natural Selection)
Nothing in Biology Makes Sense Except in the Light of Evolution
Theodosius Dobzhansky – 1973
We are living through an epidemic of chronic diseases. Heart disease, stroke, diabetes, obesity, and cancer are everywhere along with such emotional issues as depression and anxiety. Modern medicine is making massive investments in attempts to manage this onslaught.
What’s missing is an awareness of how human beings evolved and how that evolution is the foundation to finding better solutions to the current proliferation of disease. Evolutionary medicine can provide clues into who we are, why we get sick, and what can be done to regain our health.
In his brilliant work, The Story of the Human Body: Evolution, Health, and Disease, Harvard professor Daniel Liberman puts it concisely:
“…evolution explains why our bodies are they way they are, and thus yields clues on how to avoid getting sick.”
The human body, and its dietary requirements, evolved slowly over millennia in a wide array of natural environments. As hunter-gatherers we, out of necessity, ate wild plants and animals in various proportions depending on the climate, topography, food availability, etc. Our nutritional needs were closely coordinated with our surrounding landscapes. The food at hand was what nature provided. We gathered vegetables, fruits, berries, roots, and hunted animals and fish. This process started nearly two million years ago during which time a dynamic body/environment relationship was established.
The issue today is that the industrial, urban environment that we have created is radically different from anything we have encountered in our long evolutionary history.
Unfortunately, this has led to a mismatch between our genes, nutritional needs and the copious amounts of industrial, processed foods we now consume.
Evolutionary mismatch is a key concept in modern evolutionary biology. This idea helps us understand why we are suffering from so many chronic diseases.
In Nesse and Williams’ groundbreaking work Why We Get Sick: The New Science Of Darwinian Medicine, they demonstrate our struggle with the modern environment:
“Natural selection has not had time to revise our bodies for coping with fatty diets, automobiles, drugs, artificial lights, and central heating. From this mismatch between our design and our environment arises much, perhaps most, preventable modern diseases. The current epidemics of heart disease and breast cancer are tragic examples.”
Obesity is particularly suited as an example of our evolutionary mismatch with modern, industrialized society. Obesity is rampant in industrial nations and is proliferating throughout the world as Western diets are adopted. Melissa Manus of the Department of Evolutionary Anthropology at Duke University explains that:
“Due to variation in food availability and quality, the ancestral environment favoured efficient energy extraction and storage. These once-adaptive traits become mismatched to industrialized settings with an overabundance of easily accessible, calorie-dense foods. This surplus, coupled with the relatively low energy output required by the modern lifestyle, promotes an energy imbalance that contributes to weight gain.”
Our metabolism was designed for environments drastically different from our own. We are out of sync with our genetic inheritance. This mismatch has accelerated in the last 50 years. According to the Pew Research Center Americans are consuming 23% more calories now than in 1970. Nearly half of these calories come from flour and grains (23.4%) and fats and oils (23.2%). Tellingly, we are eating fewer fruits and vegetables (7.9% from 9.2%).
Research on BMJ Open documents that ultra-processed foods comprise nearly 60% of the American diet with 90% of that energy intake from added sugars. Shockingly, this means that 82% of Americans eating ultra-processed foods are exceeding the recommended allowance of 10% energy from added sugars.
The Department of Human Health and Services (DHHS) estimates that:
“Two hundred years ago, the average American ate only 2 pounds of sugar a year. In 1970, we ate 123 pounds of sugar per year. Today, the average American consumes almost 152 pounds of sugar in one year. This is equal to 3 pounds (or 6 cups) of sugar consumed in one week!”
So What Diet Is Best?
Before answering the question, and I promise to answer it soon, let’s look at the diets of two groups of people presently living and experiencing good health but are very different from ourselves.
What Can Hunter Gatherers Tell Us About Health?
You may remember the study published in the Lancet in 2017 of the Tsimane, a hunter gatherer tribe living in Bolivia. They live a lifestyle of subsistence hunting, gathering, farming, and fishing.
The shocking news was that the researchers found that the “Tsimane, a forager-horticulturalist population of the Bolivian Amazon with few coronary artery disease risk factors, have the lowest reported levels of coronary artery disease of any population recorded to date.”
85% of those studied had no CAC score. 13% had scores of 1-100 and 3% had a score of over 100.
Even those over 75, 65% had a score of 0 and only 8% had a CAC score of over 100.
This is a five-fold lower incidence than in industrialized populations.
The researchers indicated that “obesity, hypertension, high blood sugar, and regular cigarette smoking were rare.”
"The diet of the Tsimane was composed largely of complex carbohydrates (72%) high in fiber such as rice, plantain, manioc, corn, nuts and fruits. Protein constituted only 14% of their diet largely from animal meat caught in the wilds. Their diet is very low in fat with only 14% of their calories being fat calories."
The Hadza of northeast Tanzania, has been studied for over a decade by Herman Pontzer, a Duke University Health Institute professor. He found that the Hadza diet consists of food found in the forest such as wild meat, tubers, wild berries, and honey.
Robin Smith reporting on Pontzer’s work writes of the Hazda that: “By most measures they enjoy superb health. Obesity is rare. Heart disease and diabetes are almost unheard of. Their waistlines don’t expand, nor do their blood pressures creep up with age. Adults often live into their 60s, 70s, even 80s, without benefit of statins or urgent care centers.”
What’s true of the Hazda is true of most other hunter gatherers that exist today. Their diets are variable but are based on natural, non-processed foods ranging from wild meat to copious amounts of honey.
Another lens through which to discuss healthy diets is to explore what are called Blue Zones. These zones are areas of the world studied by Dan Buettner and made famous in his best-selling book, The Blue Zones Solution. Buettner studied areas that were identified as hot spots for longevity. In conjunction with the National Geographic Society, Buettner spent over a decade visiting areas that had concentrations of people over 100 years old and had grown old without high levels of heart disease, diabetes, cancer, and other chronic conditions.
The areas identified included:
· Ikaria, Greece
· Okinawa, Japan
· Ogliastra, Sardinia
· Loma Linda, California
· Nicoya Peninsula, Costa Rica
Buettner identified nine characteristics of the Blue Zones that all the inhabitants shared:
1. They move naturally. Blue Zone people don’t exercise but they are very active walking, gardening, etc.
2. Have a sense of purpose. They have a reason to get up in the morning, a purpose in living.
3. Practice stress management. Built into the Blue Zone lifestyle is a way of managing stress, either through prayer, napping, a happy hour or remembering ancestors.
4. Follow the 80% rule: they stop eating when they are 80% full and eat their largest meal in the morning or early afternoon.
5. Eat mostly plants. Meals consist mostly of beans, soy, lentils, etc. Meat is eaten about five times a month.
6. Drink wine in moderation.
7. Are members of faith-based communities.
8. Believe family comes first. Ageing parents are kept close and cared for.
9. Have close friendships, with many lifelong supportive relationships.
For our purpose, let’s look at the diet aspect of the Blue Zoners.
The Blue Zone Diet
Eating a Blue Zone may help us to live longer and healthier.
In Ikaria, Greece they eat goat’s milk, honey, legumes, wild greens, some fruit and a small amount of fish.
Okinawans eat bitter melons, tofu, garlic, brown rice, fish, shiitake mushrooms, and drink green tea.
Sardinians consume beans, fennel, chickpeas, tomatoes, almonds, and drink milk thistle tea and wine. They also drink goat’s milk and sheep’s cheese along with flat bread, sourdough and barley.
The top foods of the Seventh Day Adventists on Loma Linda, California are avocados, salmon, nuts, beans, oatmeal, whole wheat bread and soymilk.
The Costa Ricans eat papayas, yams, bananas, peach palms, rice, beans, cheese and cilantro.
What can we learn about our diet from hunter-gatherers and Blue Zone inhabitants?
The first is that there is no one best diet. Both hunter-gatherers and Blue Zoners eat a wide variety of foods. Hunter gatherers and those in contemporary blue zones eat the natural foods available to them.
There are several things that they all share and which we may consider emulating:
· Reduce unhealthy processed food (low-fat foods, crackers, salad dressings, cookies, breakfast cereals, whole-wheat loaf bread) and ultra-processed foods (soft drinks, chips, candy, cake mix, flavored yogurt, Chicken nuggets, fast food burgers, hot dogs). Doing this will reduce your intake of salt, as well as minimize added and excess sugars.
· Reduce caloric intake by 20 to 25% depending on your weight. Don’t eat until you are full. Eat until you are no longer hungry (the 80% rule).
· Reduce meat to a few times a week. There is no need to become a vegan or vegetarian. Some hunter-gatherer tribes eat more meat than others. Blue zoners eat meat regularly but not daily.
· Eat natural, whole foods whenever possible. Foods such as beans, vegetables, mushrooms, whole grains, fruits, cheeses, herbal teas, natural yogurt, tofu, brown rice, sweet potatoes, and nuts and seeds should be the bulk of your daily meal plate. Here is a list of whole foods you can choose from.
· A natural foods diet will increase your fiber intake substantially. This is very beneficial for your health and microbiome. Aim for at least 30 grams a day or more.
· Drink wine in moderation. There are a lot of down sides to alcohol so be careful.
· Don’t worry about dieting. Your body will respond to a natural food diet which is naturally low in calories. No need to do calorie counting.
Humans evolved to eat a wide variety of natural foods. This ability made it possible to spread throughout the world in a wide range of conditions and habitats. There is no single best human diet. But there are certain ways of eating that augment our health and vigor and correspond to our evolutionary needs.
To be healthy while living in our modern, urbanized environments takes time, effort, and commitment. We are not constituted to eat mass produced processed and ultra-processed food products.
However, it’s not presently possible or even desirable to return to our primal roots or to past rural subsistence farming lifestyles.
What we can do is learn from our evolutionary past and from our not so distant ancestors, that it’s possible to create compensatory behaviors that mimic a healthy human diet. We need to shun the modern, unhealthy, artificial diets that have become normal and are the basis for the epidemic of chronic diseases ubiquitous in our culture. The acronyms say it all: SAD (standard American diet) and MAD (modern American diet).
It takes time to feel comfortable with what at first seems unnatural. But we can learn to appreciate and fully enjoy a whole, natural diet and lifestyle.
Following the diets of those in the Blue Zones and our hunter-gatherer ancestors is one way to start on the path to wellness. Explore a wide variety of healthy diets. There may not be one diet that suits you. Think of it as an ongoing journey. Have fun trying the many different foods and combinations available to you. Start small or jump totally in. The choice is yours Nature can provide us with what we need to live long, vigorous, and healthy lives.
Check out the Blue Zone Diet
Part 2 of this series will be on our fitness needs in light of evolution and our sedentary lifestyles.
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