Ever wondered why it’s so hard to walk past your favourite ice-cream parlour? Or why you’re sent into panic over a strongly-worded email? Basically, humans weren’t built for the 21st century. The good news? There are ways to train your brain.
Our prehistoric ancestors enjoyed a far easier and, arguably, happier existence, says historian Yuval Noah Harari. We “didn’t have to deal with automobile accidents or industrial pollution,” he writes in his book Sapiens: A Brief History of Humankind. There were “no floors to polish, no nappies to change and no bills to pay”.
There was no need for sleeping pills, digital detoxes or deep-tissue massages. All our meals were organic, free-range and non-GMO. We lived in mobile tribes with few possessions and little pressure, far from skyscrapers, fast food, traffic and 24-hour news cycles.
Our modern world “gives us more material resources and longer lives than those enjoyed by any previous generation, but it often makes us feel alienated, depressed and pressured.”
In short, the gap between human nature and our contemporary environment is harming our physical and mental health.
Fortunately, our sophisticated survival systems have a secret weapon: They’re highly adaptable, meaning you can train your brain. Humans thrived because of our ability to communicate and learn, and by harnessing that power, we can adjust to overcome our basic instincts.
The evolution of our diet through the ages
Once upon a time, long before Uber Eats and microwaves, we humans hunted protein-rich food and gathered roots and berries. If they were sweet, we’d fill our stomachs. If they were sour, we’d keep away. We had finely-tuned survival instincts so we could bolt if we sensed a tiger snake nearby. We formed strong social bonds because isolation meant death. It wasn’t all strawberries and naps in the sun, but life was simpler.
Our appetites evolved to nourish and protect us. Sweet, calorie-dense foods enticed us to eat as much as possible so that we could store energy for times when things were lean.
So if you’re wondering ‘why am I always craving sugar’, sugar cravings were a crucial survival mechanism.
“A typical forager 30,000 years ago had access to one type of sweet food – ripe fruit,” Dr Harari writes.
“If a stone-age woman came across a tree groaning with figs, the most sensible thing to do was to eat as many of them as she could on the spot before the local baboon band picked the tree bare.”
He calls this the “gorging gene”. There are no local baboons marauding around Australia’s suburbs, yet that gluttonous urge means the compulsion to eat as much cake as possible is real. In an age of abundant processed, fatty, high-sugar and high-salt treats, our hardwired predilection for calorie-dense food is leading the entire population astray.
The problem is so pressing that in July 2023 the Independent federal MP Dr Sophie Scamps introduced a bill to ban junk food advertising between 6am and 9.30pm.
“Two-thirds of adult Australians and one-quarter of our children are above the healthy weight range,” she said. She recognises that when modern conditions meet stone-age impulses the outcome can be disastrous.
“We evolved these taste profiles based on a situation where we had scarcity of foods,” molecular nutritionist Dr Emma Beckett explains. “The people who survived would’ve been those able to eat a large amount through the feast time, so they were able to survive during the famine time.”
How to stop sugar cravings
If you’ve ever given a child bitter or sour food, you’ll know they pull faces and spit it out. But over time they can grow to tolerate and even like food with strong flavours.
“Your brain learns they’re not going to kill you. It learns you’re not eating poison.”
These are lessons we can apply as adults. You can wean yourself off the sweet stuff by slowly reducing sugar in your diet.
“Dial back the amount of sweetness,” Dr Beckett says. But do it gradually, or it won’t work.
But, Dr Beckett doesn’t advocate a return to stone-age eating either, such as following the paleo diet.
When people were eating a paleo diet (because they lived in the Paleolithic Era) “those people were not living into old age, so they didn’t have to worry about things like colorectal cancer and heart disease.“
So, is a paleo diet healthy for this day and age? “The diet you choose now should be the diet that’s going to set you up to live well in old age,” he says.
How to eat healthier
In our time-poor lives, convenience has become a major influence on our food choices. “It’s not humans that have changed, it’s society that’s changed,” Dr Beckett says. And convenience often means ‘fast food’.
Meaningful change at a population level requires government policy that makes fresh food more accessible and cooking at home easier. But there is action we can take to help our prehistoric brains navigate this fast-food world, such as prepping meals when you have time and energy or making it easy to access healthy snacks.
“If you’ve got a whole melon sitting on the bench, you’re probably not going to crack it when you’re hungry,” says Dr Beckett. “But it you’ve cut up the melon and put it in the fridge, when you’re feeling snackish you’ll probably grab it.”
What is our fight or flight instinct?
As our appetites developed to sustain us, so too our limbic system evolved to keep us safe. Unfortunately for modern humans, this efficient internal alarm has trouble distinguishing between the threats ancient humans faced (saber-tooth tigers) and threats that modern humans face (angry emails).
We’re all familiar with the term “fight or flight”. That’s essentially our limbic system kicking into gear.
“Our primitive survival mechanism responds to threats in our environment [in a way that] served us way back in primitive times,” says science journalist and broadcaster Lynne Malcolm, author of All in the Mind. “Our brain responds to threats in the same way it always has.
“Your heart rate and blood pressure increase, causing extra blood to flow to the muscles to help you get out of danger. Sugars and fats pump into your bloodstream. You begin to sweat so you can keep yourself cool. Your brain is relatively quiet and very focused. This response is designed to save your life.”
This fight or flight instinct can be relentless. We did not evolve to endure the endless pressures of modern life. If we don’t take time out to rest, relax, play and restore ourselves, the stress can build up. This is known as the allostatic load, and it causes anxiety and stress which can manifest in many ways.
“Once you get an overload, this can accelerate ageing and associated illnesses right down to the DNA in our cells,” Lynne adds. Compounding the problem is our lack of leisure. Our forebears had far fewer demands on their time. As Dr Harari writes in Sapiens, modern hunter-gatherers hunt one day out of three. Gathering takes three to six hours. In contrast, those of us in the industrialised workforce labour 40 to 45 hours a week.
What can trigger anxiety?
Other ancient worries weigh on us. A fear of being judged or rejected looms large in many people’s lives. This too has its roots in evolutionary necessity. “In Neanderthal times, if you were excluded from the group, it’s likely you’d die. Social anxiety would have served as a warning to individuals that they were at risk of rejection,” Lynne says.
Happily, just as we can coach our appetite into healthier habits, understanding why we’re panicking over perceived threats can help us reduce the severity of the fight-or-flight response. One technique is to think of your worries as books that you acknowledge, then put on a shelf. “Just stop and think, ‘Wait a minute, I’m not going to die. This isn’t going to kill me. I still have all these other things in my life’,” Lynne says.
Thinking about why you are feeling anxious or emotional or outraged can help you gain perspective and control, Lynne says. “Stepping back a bit and going: What is really important? What matters, and how is this worry or anxiety bossing you around? You’re not in control. It’s in control of you.” Once you’re aware of what’s happening, you can take the reins.
She also advocates cultivating a habit of meditation. “If you’re really freaked out by something, have five minutes focusing on gentle breathing, rather than all the other stuff worrying you. That can be a quick-fix thing that can give you that time to break the circuit.”
How to train your brain towards delayed gratification
In modern society we need to put aside money to pay bills and save for retirement. Our jobs leave us no time to hunt and gather, so we do meal prep. We allot time to exercise. All of this requires forethought and delayed gratification – something our stone-age brains are not renowned for. Behavioural scientist and author of Get it Done, Professor Ayelet Fishbach, says we’re now required to act in ways that traditionally have had no evolutionary value, and thus go against our nature.
“We expect everyone to save for retirement for years. Really, there was no need to do this until very recently in our development,” she says. In order to save, we must override our internal reward systems. The dopamine hit from an impulse purchase is immediate. The benefits of squirrelling away cash are harder to see.
“We’re not designed to plan for 20 years ahead,” Prof Fishbach explains. “There were no bank accounts or even freezers in our species’ evolution.” When choosing between an immediate reward and a future reward, our impulse is to opt for instant gratification. Classic behavioral studies show this evolutionary phenomenon at play. When presented with a small reward sooner or a large reward later, pigeons always opt for a few grains after two seconds, rather than many grains after 10 seconds.
However, Prof Fishbach says, pigeons can be trained to wait for a bigger windfall. And we can do that too. Creating barriers to spending “allows self-control to kick in,” she says, and this is particularly useful as we wrestle with a new adversary: online shopping. The quick dopamine hit when we click ‘buy’ is very seductive. An effective way to avoid the impulse purchase trap is to introduce a time buffer. Put the item in your cart, then walk away. When trying to save, instead of creating barriers to spending, remove barriers to saving. It’s something we’ve seen our government implement with compulsory superannuation.
On the subject of temptation, Prof Fishbach says the adage of “forewarned is forearmed” rings true. “When people know about temptation in advance, it’s like inoculation. You know it’s coming so it’s easier to resist it.” Tricks like these do work. While an absence of “life-and-death pressure” means it’s unlikely our physiology is going to catch up with our smartphones, ice-cream and online shops any time soon, Dr Beckett says that doesn’t mean our fate is fixed.
Our adaptability acts as a failsafe that protects us in an ever- changing world. “Even though it’s in our biology, it’s not inevitable,” she says. We can train our prehistoric brain.