The universal strategy for success, in my view at least, is simple: find the most successful people/populations/organisations in the world, and see what they all have in common. What do they all do to achieve success? What do they all not do to achieve success?
And so this has always been my strategy for human health. Find the healthiest people on earth, and do what they do while avoiding what they avoid.
These people, from what I have researched, are the hundreds of hunter gatherer tribes from around the world. And it makes sense on the face of it. For approximately 2.4 million years, since the human genus emerged, we have survived as hunter gatherers (1). That’s roughly 84,000 generations (2). These people lived the way humans were designed to live. So living the way they did will result in health just as impressive as theirs. If you take an animal from the wild for instance and put it into a zoo, you would feed it what it naturally ate in the wild wouldn’t you? To do anything else and expect the animal to do as well would be foolhardy and quite frankly arrogant.
By contrast, we have had agriculture for about 10,000 years (or 350 generations (3)). As an illustration of how long we have been eating this way, if all of human history (2.4 million years) was distilled into 24 hours. Then the first 23 hours and 54 minutes would represent our hunter gatherer diet, and only 6 minutes on the clock would be how we have lived on agriculture.
To figure out the best diet for humans to be on, we need to look to the healthiest people in the world, and these people are the hunter-gatherer tribes who live the way our 2.4 million year genes are used to living.
But there’s a few issues with this train of thought that I’m sure you’ve already thought of: like that these populations don’t live all that long, or that they’re genetically protected from diseases right?I’ll get to these issues in a second.
Hunter Gatherer Health
But first, let’s take a look at the health of these populations and see if they are indeed as healthy as I’m claiming:
There have been many studies done on the health of these hunter gatherer societies. These studies have shown the following (note: each of these references represents at least one and sometimes up to 6 individual societies):
- They are all very physically fit (4) (5)
- Their blood pressure is low and does not fluctuate significantly with age (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)
- They have excellent insulin sensitivity throughout their lives, even in old age (5)(13)(14)(16)(17)(18)(19). Even in spite of a very high carbohydrate diet (ref 19)
- They had excellent cholesterol levels (5)(18)(14), despite a large proportion of these populations subsisting primarily on animal foods (20).
- They had low weight and body fat percentages, which did not increase with age. (5)(9)(14)
- They didn’t get of diabetes (9) (12) (18)
- Heart disease was very rare relative to the western world (2)(4)(9)(13)(20)
- Cancer was very rare or non-existent (9)
- They’re bones were very healthy and they had low fracture rates (4)(9)
- They had well-formed teeth and jaws with very few or no caries (4)
Overall this paints a picture of a very healthy population. And while there were outliers like the Inuit, who have been argued to not be as healthy as the above, these people were unequivocally healthier than we are in the western world.
And remember, these people didn’t have access to hospitals, antibiotics or even antiseptics. So their good health is even more remarkable.
Despite having no access to hospitals and medicine, these populations lived lives almost completely devoid of western diseases.
So we have proven that they are very healthy cultures. But what about the claims that they didn’t live long enough to get diseases? Or that their genes or exercise levels protected them?
Let’s take a look at each of these points, and a few more to see if they have any merit:
Contrary To Conventional Wisdom, They Lived A Long Time
When researchers looked at these populations to determine how long they lived, they found something interesting. When these people made it past childhood, they lived into their 70’s, 80’s and even 90’s (21). Conventional wisdom has always assumed that these people live for very short periods of time, but the reason for this is because of high infant mortality. In the study looking at mortality rates the researchers found that only 57% of children born in hunter gatherer societies made it past the age of 15. This skews mortality rates significantly. When these are adjusted for, it’s very common for these people to live into their 70’s, 80’s and even 90’s.
When infant mortality is taken into account, many hunter-gatherers lived well beyond 70.
They’re Not Genetically Resistant To Disease
These populations have lived like this for tens of thousands of years, so it would make sense that many of them would genetically adapt to their environment and therefore become resistant to diseases associated with their food. A high meat intake for instance. But in every study done on these populations, researchers find that they get western diseases at the same rates, or even higher rates when they switch to a more western lifestyle (ref 18)(ref 19)(22) . This means they are not in fact genetically immune or protected from disease. And in fact many, like the Tukisenta of Papua New Guinea are actually more prone to diseases like diabetes.
When these populations switch from their natural diet to that of the west, they get western diseases as quick or quicker than westerners do. Indicating they aren’t genetically resistant.
We’ve Evolved In The Last 10,000 Years, But Not Enough
Yes it’s true, our genes have changed in some pretty important ways in the last 10,000 years. For instance lactose tolerance has significantly increased (23). And this is an argument put forward to support the fact that we can handle such a radically changed diet. Lactose tolerance has increased so why wouldn’t we be able to adapt to the other changes in our diet? Like grains.
Well, there is a problem with this. Lactose tolerance, for instance, relies on a specific enzyme being produced called lactase.
As you probably know, lactose is a sugar found in all mammalian milk. So human mothers naturally produce lactose in their milk. The body produces an enzyme called lactase to break down the lactose in the milk. Every baby has this enzyme, and a gene controls how long the baby will be able to produce it. Historically this gene switches off once the baby moves away from breast milk, thus stopping the baby from being able to handle lactose. However nowadays around 2/3rds of the population worldwide can handle lactose (24). Because this gene has stopped being turned off.
And so we come to the reason why this isn’t the same as being able to metabolise other new things in our diets. Being able to handle lactose in adulthood is simply a matter of keeping the switch on for a gene. Where as handling foods like grains would require evolving an entirely different gene. It’s the difference between being born with webbed feet, relative to developing gills.
While we have experienced small genetic changes since the advent of agriculture, we haven’t changed out genes enough to be able to tolerate such a big change in diet.
Exercise Can’t Explain Their Good Health
Indeed on average hunter gatherer societies exercised far more than we do in the western world. They needed to go out and hunt their meat, they needed to walk for miles to forage for their plant foods. But there are exceptions to this rule. A study done on the Hadza of Northern Tanzania for instance found that although they did exercise a little bit more than we do in the western world, their average energy expenditure was no different to the westerners that they used as a comparison group (25).
Additionally, typically the men were hunters and the women were gatherers in these cultures. The men’s energy expenditure was significantly more than what we are used to in the western world. But typically women expended less energy in these cultures and there is no evidence to suggest that the women are less healthy than the men in these studies.
And adding to this the fact that exercise is not a panacea. It’s protective and does help disease, but it’s not the be all and end all. Exercise simply cannot explain the supreme health of these populations.
Exercise, while helpful isn’t a panacea to health. It can’t explain the health of these societies.
What’s Natural Isn’t Necessary Healthy
The final argument against adopting the same lifestyle that these populations have refers to what’s called the appeal to nature fallacy (26). The thought process goes like this: something is good or healthy because it is natural and something is bad or unhealthy because it is unnatural. This line of thinking makes sense on the face of it, but it is riddled with holes when you take a closer look, and especially if you apply this rule with no thought to what you’re doing.
People who oppose the idea of adopting the same lifestyle as these hunter gatherer’s often cite this as a reason why it’s a foolish idea. And they are right, adopting everything that they did would not make sense.
But this argument completely misses the point. Using the success of these populations and their lifestyle as a guide is not a concrete set of rules like “well these societies did this so I must to do same”. Instead, it’s a logical framework for analysing specific things that they did and adopting those that have good evidence in favour of them, and discarding those that don’t.
As an example, they didn’t disinfect or filter their water, but no one is arguing that we shouldn’t do that. Just because the populations above didn’t drive cars, use computers or filter their water doesn’t mean that we can’t do those as well. The idea behind eating this way is to take what they do that leads to healthfulness, and to leave the rest behind.
Concluding that what is natural is healthy and vice versa is incorrect. Paleo is a logical framework for figuring out what is and is not good for the human body.
So let’s get to the next question:
What Did These Populations Eat?
Well a group of researchers in 2000 set out to find this out (Ref 20). They looked at 229 hunter gatherer tribes from around the world and this is what they discovered:
- Hunter-gatherers preferred to get their calories from animal products whenever this was possible. From the authors: ” Our analysis showed that whenever and wherever it was ecologically possible, hunter-gatherers consumed high amounts (45–65% of energy) of animal food.”
- The vast majority of these societies got more than 50% of their calories from animal products. From the authors: “Most (73%) of the worldwide hunter-gatherer societies derived >50% (≥56–65% of energy) of their subsistence from animal foods, whereas only 14% of these societies derived >50% (≥56–65% of energy) of their subsistence from gathered plant foods.”
- They did not find a single population that subsisted entirely on plant foods. from the authors: “No hunter-gatherer population is entirely or largely dependent (86–100% subsistence) on gathered plant foods, whereas 20% (n = 46) are highly or solely dependent (86–100%) on fished and hunted animal foods.”
- The societies made use of the entire edible animal. The muscle meat, organs, bones, marrow etc were all consumed.
- There was a very wide array of macro-nutrient ratios in these populations. From the authors: “Our data clearly indicate that there was no single diet that represented all hunter-gatherer societies”. The authors estimated the following: Fat intakes were found to be as low as 28% of calories and as high as 58%. Protein was found to be as low as 19% protein and as high as 35%. Carbohydrates were found to be as low as 22% of calories and as high as 40%. (Although we know from the Tukisenta of Papua New Guinea that carbohydrates intakes can get much higher, as they subsisted on almost 95% sweet potatoes).
These calories came from a very wide array of plant foods: fruits, nuts and seeds, dried fruit, flowers, gums, roots and tubers, leafy vegetables. And animal foods: organ meats (liver, kidneys, tongue etc), muscle meats, connective tissues, tendons and ligaments, cartilage , seafood (fish, crustaceans etc). It seems that these people picked their foods based on nutritional as well as caloric requirements.
Research shows that these populations lived on a wide array of plant and animal foods when available. They predominantly got their calories from animals products, but this is by no means a rule as there were many that did not.
What Can We Learn From These Populations?
1. There is no single “hunter-gatherer” diet.
Each of these 229 hunter gatherer populations has a diet that is unique to them. There are the extremes of the Inuit who get almost all of their calories from animal products, to the Tukisenta who get 95% of their calories from sweet potatoes. Both of these populations are very healthy compared to western populations, and so we can conclude that the human body has a tremendous ability to not only survive, but to thrive on these two extremes and anywhere in between.
2. While meat eaters were more common, many cultures lived healthily with minimal amounts (but not zero) of meat
Not a good point if you’re a vegan here. It’s pretty clear that not one of these populations lived without the use of animal foods. The Tukisenta are the most extreme of the hunter gatherers in their intake of plant foods (95% from sweet potatoes), however they still made use of animal foods when possible. What we can conclude from this point is that while animal products have never been completely absent from the human diet, the amount of meat that the human body can live on (historically speaking), is not very high. But it is still present.
3. There is no perfect macronutrient ratio
From the vast array of the diets that these people subsisted on, we can conclude that there is no perfect macronutrient. There is a range that we know the human body can thrive on, and if you eat within this range then there is no reason to believe you can’t be completely healthy.
Although when certain diseases set in, there is merit in altering micronutrient ratios to see what effect this would have on you. But this will come down to individual preferences and how the body reacts. The best way to study this is to test yourself. But remember, carbohydrates per se aren’t as bad as we thought they were. Macronutrients distract us from what is actually healthy.
4. Hunter Gatherers ate the entire animal, not just the muscle meat
Many people when they adopt a diet like this start eating a heap more meat than they otherwise would. I have even read somewhere that they throw the muscle meat to the dogs if they’ve had their fill. But eating more muscle meat is really not that healthy, there are vital nutrients in the rest of the animal that are lacking in the muscle meat. It’s important to eat the whole animal from head to toe. Muscle meat for instance is very high in methionine (an essential amino acid) (27), but too much can have negative effects on the production of homocystiene (28). Which is mitigated by glycine (which is found primarily in collagen) (ref 28).
5. While these populations ate a vast array of foods, pointing to no specific diet, they all avoided the same foods
While we can’t point to any specific diet that these people lived on, we can look at what they universally didn’t contain. And they are the following:
- Improperly prepared grains
- Excess sugars
- Vegetable oils and spreads
- Processed foods
If we avoid these foods, while adding in whole, unprocessed animal and plant foods, we will likely see health that can rival those of our hunter gatherer friends.