Learning from our hunter–gatherer past
Evolution is the optimisation of survival. It’s not surprising, then, that we can learn at lot by looking at health from the viewpoint of evolution. It can help point us towards ways to work with our long-evolved physiological and psychobiological systems, rather than trying to battle against them.
STRESS
Take stress for example. Going back to our hunter–gatherer past, we are optimised to cope with, and even to thrive on, short bursts of often physically demanding stress – running away from a predator, homing in for a tricky kill while out hunting – with the rest of the time in low-stress ‘rest-and-digest’ mode. Those same stress hormones that served us so well when we needed to optimise for ‘fight-or-flight’, can be hugely destructive to health in the form of chronic stress, in all its forms whether that’s from a bullying boss, an abusive partner, the less dramatic but equally damaging problems of loneliness, grief, financial worry or the general mix of day-to-day anxieties. While the ideal solution to some stresses are to make changes to remove the stress-inducing person/situation from our life, many of us benefit from becoming aware of what stress can do to the body and learning to manage stress better.
Preparing for fight or flight
One of the the most dangerous effects long-term stress is that the blood becomes more coaguable (clotty). This makes entire sense from an evolutionary point of view because as it really is the fight-or flight response, the body is getting ready for potential injury. ‘Supercharging’ the clotting response when there’s a real-world risk of injury has a huge survival advantage. But when we maintain a level of chronic stress this increased clotting tendency puts our cardiovascular health at risk.
The release of stress hormones affects our metabolism too. If you need to run or fight, your body is not going to prioritise normal energy storage. Stress hormones promote the creation of immediate-use energy available through a range of mechanisms that increase blood glucose, and boost glycogen, fat and protein breakdown – all useful immediate fuel! But when stress hormones are chronically high and this released energy does not get used up in physical action, it is re-stored as fat around the abdomen. And, over time, the ultimate effect of high levels of stress hormones is towards insulin resistance.
‘Shake it off’
It’s been observed that animals know how to dissipate stress. After being chased by a predator, they will shake and tremble which helps dissipate the stress hormones and calms the nervous system. US psychotherapist Peter Levine asserts that prey animals are under the threat of death but don’t develop ongoing trauma or PTSD because of this physical release after the threat has gone. Whether its because a modern human’s day-to-day stressors don’t need a physical response (running or fighting), tend to be chronic or longer-lived, or because we have lost contact with our physical stress-release responses, we humans appear to really suffer both acute and chronic effects of our stress. This has led a number of therapists to advocate the use of somatic therapy or shaking exercises to help release both day-to-day stresses as well as heal long-term trauma. It makes sense to me that any form of physical release after stress, whether its jogging or dancing, punching some pillows, having a good sob or moan, be far healthier than a stoical approach and a ‘stiff upper lip’.
Other ways that can help to stop us getting stuck in ‘fight-or-flight’ include forms of breathwork, meditation and vagus nerve exercises. I’ll explore these in another article.
FOOD
A hunter–gatherer diet
What can we learn about food and diet from our ancestors? Well for a start, before humans settled and started to farm the land, they ‘hunted’ and they ‘gathered’. Returning to a diet more akin to those of pre-agricultural times is the idea behind the Paleo diet, which essentially restricts/removes grains, legumes, dairy and, of course, processed foods – and instead focuses on vegetables, nuts and seeds, fruit, meat and fish. The idea is that humans have had much more time to become suited to the hunter–gatherer diet makes some sense, although critics would argue that it uses a greatly oversimplified view of the evolutionary influences on human diet. However, I think that using this idea as a gentle pointer to help us choose a physiologically kinder dietary composition may have some value.
The microbiome
One of the fall-outs of our modern diet and lifestyle has been its effect on our gut flora. We are now starting to have a greater understanding about the importance of a healthy gut microbiome; we know that having a stable and diverse range of gut microbes is beneficial and helps lower risk of disease. The modern Western diet is associated with a less diverse microbiome than that of indigenous populations eating a traditional diet. One of the most studied groups in this respect is the Hadza, one of the last-remaining hunter–gatherer groups in Africa. Some researchers are now starting to talk about how we can ‘rewild’ the gut microbiome. A diet of natural food is certainly at the heart of this, ideally including some traditional fermented foods, such as yogurt, kefir and/or lacto-fermented veg. Other factors in the modern world also have a negative impact on our gut microbes, including stress, over-cleaning, antibiotics and medications, living more separately rather than in larger groups, and limited early-years microbial exposure.
Intermittent fasting
It’s not hard to imagine that for a hunter–gatherer, it’s not a matter of three square meals a day plus snacks! In an article by Professor Tim Spector (of ‘ZOE’ COVID study fame) about his mini-experiment exploring the effect on his microbiome on going to live with the Hadza for a number of days he addresses the issue of intermittent fasting as a natural byproduct of that lifestyle. We know now that having regular extended periods without food is very beneficial to metabolic health. The easiest way for most of us to do this is by extending the period between our last meal of one day and our first meal the following day, whether that’s by skipping breakfast or just eating dinner early and breakfasting late.
EXERCISE AND SUNLIGHT
Thinking about human history, its easy to see that we are not made for sitting at a desk all day and sitting on a sofa all evening. In fact, some researchers have also been considering the fact that, for longevity and long-term health, we appear to be best adapted for a ‘hunter–gatherer exercise regimen’. What this means is that we are ideally made for:
- relatively high levels of energy expenditure on a day-to-day basis, made up of:
- a large portion of low- to moderate-level activity (equivalent to the hunter–gatherer’s daily activities of foraging, building/maintaining shelters, walking, getting water, the low-intensity aspect part of a hunting day)
- shorter periods of high-intensity activity (equivalent to hunting, or at least the most intensive parts of a hunting day)
- days with higher exercise intensity are followed by more restful days
- activities involving social connection
So it would seem that for most of us, increasing our background activity level of the ‘chop wood, carry water’ variety – whether that’s cycling or walking to work, walking the dog, digging the garden, swimming – together with some high-intensity interval training (HIIT), so short bursts of intense exercise, is ideal. HIIT has been shown to greatly improve cardiorespiratory fitness, promotes abdominal weight loss and improves glycaemic control. So, it offers huge benefits to our metabolic health.
The social aspect of exercise is also emphasised by many authors – exercising with others and out in nature is not only good for the body, it’s good for the soul. This also emulates the lifestyle pre-industrial and pre-farming communities whose shared endeavors and experiences were not only bonding events but were also for the good of the tribe. Whether your ideal Sunday is a cross-country ramble, a community green-gym project or a game of football, it’s all good. I’ve written before about the great benefits of sunlight, both through its effects on vitamin D production and also nitric oxide. Most of us can really benefit from spending more time out of doors and increasing our daily sun exposure, just as our ancestors did.
It’s difficult to battle tens, if not hundreds, of thousands of years of adaptation. While I’m not suggesting we ditch the food shops and forage every meal from the local woods, I do think that looking at health through an evolutionary lens can be very enlightening.
FURTHER READING / VIEWING / LISTENING
Nourish Balance Thrive Podcast: Rewilding the Gut: Restoring Ancestral Diversity to the Microbiome
I spent three days as a hunter-gatherer to see if it would improve my gut health
Image by Gruban, CC, Algerian Desert, via Wikimedia Commons
