Up until about 12.000 years ago, all humans lived as hunter-gatherers. This was how things had been for millions of years. Today, however, very few true hunter-gatherers are left on this planet. We’ve traded in our original way of life for a modern, high-tech existence. Most people would probably say that this is a good thing. Today, we have access to food from all over the world, we can relax in our heated homes, and we don’t have to evade dangerous animals to survive or walk for hours every day to get a hold of food.
However, the abandonment of the hunter-gatherer way of life didn’t come without costs, many of which are related to chronic disease. The incidence of a myriad of chronic health conditions have skyrocketed lately, in large part because our modern diets and lifestyles are incompatible with the genetic make-up that has been handed down to us from our ancestors.
What happens if we try to reverse this process? For example by having westernized people take up an ancestral lifestyle. Let’s find out…
What happens when you take a bunch of westernized people and send them into the wild to live as hunter-gatherers?
More than 20 years ago, a seminal study was published in the journal Diabetes. The study, entitled Marked improvement in carbohydrate and lipid metabolism in diabetic Australian aborigines after temporary reversion to traditional lifestyle (1), investigated what happens to the health condition of westernized people when they adopt a traditional, hunter-gatherer lifestyle. The participants in the study were ten overweight, diabetic Aborigines from the Mowanjum Community (Derby, Western Australia) who all agreed to spend 7 weeks in the wild, living as hunter-gatherers in their traditional country in northwestern Australia.
Over the 7-week period, the health of these diabetic Australians greatly improved. On average, they lost 8 kilograms each. The tests performed also revealed a marked drop in fasting glucose, improved postprandial glucose clearance, increased insulin sensitivity, and a signficant fall in fasting plasma triglycerides. These changes were observed in all of the ten participants, although to varying degrees.
Here’s what the author of the study, Kerin O’dea, had to say in her conclusion:
In conclusion, the major metabolic abnormalities of type II diabetes were either greatly improved or completely normalized in this group of Aborigines by relatively short reversal of the urbanization process. At least three factors known to improve insulin sensitivity (weight loss, low-fat diet, and increased physical activity) were operating in this study and would have contributed to the metabolic changes observed. (1)
To those who are familiar with the research on Paleolithic nutrition and ancestral health, the results of this study probably don’t come as a surprise. The participants swapped out their western lifestyle, which is completely discordant with the human genome, with a lifestyle that is better matched with our biology, and hence, it’s not surprising that they lost a lot of weight and drastically improved their glucose and lipid metabolism. What may be surprising to some though – in particular those who’ve learned that diabetes is an incurable disease – is how quickly the health effects occurred. As the author of the study note, the major metabolic abnormalities associated with type 2 diabetes completely normalized in some of the participants, although the intervention only lasted 7 weeks.
This study is probably among the most important “Paleo studies” that have ever been carried out, and it’s frequently mentioned in discussions about ancestral health and Paleolithic diets. The study may be even more relevant today than it was when it was published more than 20 years ago, due to the fact that the incidence of diabetes worldwide has increased dramatically over the past two decades.
The ancestral health movement is built on a solid foundation of scientific evidence. Hundreds of scientific papers covering topics related to ancestral diets and evolutionary health principles have been published. However, no other study besides the one above has looked at what happens when westernized people head into the wild and adopt a Paleo-type lifestyle. That is, until now…
The study of origin
Two months ago, a study entitled Influence of a 10-Day Mimic of Our Ancient Lifestyle on Anthropometrics and Parameters of Metabolism and Inflammation: The “Study of Origin” was published in the scientific journal BioMed Research International (2). The scientists behind this study have published several research papers covering topics related to evolutionary health promotion in the past, including one of my favorite scientific articles of all time, Lifestyle and nutritional imbalances associated with Western diseases: causes and consequences of chronic systemic low-grade inflammation in an evolutionary context (3).
In this recent study, they recruited fifty-five apparently healthy individuals, allocated them to five groups, provided them with raw food and the basic equipment needed to survive outdoors, and sent them on a 10-day trip through the Pyrenees, a range of mountains in southwest Europe.
The participants drank water from waterholes, slept outside in sleeping bags, and were exposed to temperatures ranging from 12 to 42°C. Moreover, they didn’t have access to mobile phones or other electronic devices, ate a diet with nutritional characteristics similar to that of the diet of the traditionally living Hadzabe people in Tanzania, and walked on average 14 kilometers a day, which is roughly equivalent to the distance our Paleolithic forebears may have covered each day. In other words, they lead a lifestyle that is similar in several respects to that of hunter-gatherers.
Here’s what the researchers had to say about the reasoning behind exposing the participants to these ancient stress factors:
The absence of ancient immune challenges in current Western societies inspired us to hypothesize that acute stress from ancient danger signals causes redistribution of the immune system towards its evolutionary preferred locations and thereby favorably affects the state of chronic systemic low-grade inflammation, normalizes stress axes activities, recovers rhythmic function, and restores insulin-insensitive pathways. Mild stress factors may activate resolution responses based on survival mechanisms that originate from millions of years of evolutionary pressure. (2)
Obviously, not every aspect of a true Paleolithic lifestyle was replicated in this study, but the results are interesting nonetheless. Over the 10-day period, the body weight and body mass index of the participants decreased with a median of −3.8 kg and −1.2 kg/m2, respectively. Incredibly enough, one individual lost 12.5 kg (!!) during the trip. Several other beneficial effects related to glucose homeostasis and lipid metabolism were also observed. As for possible adverse effects, increases of ASAT, ALAT, and CRP were recorded, which may partly be attributed to high levels of physical activity, as well as gastrointestinal infections caused by drinking water.
Here’s what the authors had to say in their finishing statements:
The outcome of this 10-day “study of origin” suggests that a short period of return to the “conditions of existence” similar to those on which our genome is based may improve anthropometrics and metabolism by favorably challenging the immune system in apparently healthy subjects. The “return” may come with some costs in more active infection, as a trade-off for the “chronic systemic low-grade inflammation” typical of our current lifestyle of affluence. We may increasingly appreciate that we cannot have it all, while the evolutionary lessons of Darwin and intervention studies  teach us that prevention might be more rewarding and affordable than the current culture of medical treatment. (2)
This recent study, as well as the one from 1984, highlight the profound health improvements that can be obtained through lifestyle changes. Obviously, none of us are going to move into the wild and adopt a hunter-gatherer lifestyle; however, that doesn’t mean these types of studies have nothing to offer us.
Randomized controlled trials are very powerful, but they are limited by the fact that only a single, specific exposure is used. The studies discussed in this article, on the other hand, investigate what happens when people are instructed to completely change their whole lifestyle. This way, it’s difficult to know exactly what caused the observed effects, but the studies are clearly worth doing nonetheless. After all, chronic low-grade inflammation and the diseases of civilization are not caused by just one single factor, but rather, by many complex, often interacting factors.