The paleo fantasy provides a lesson in the reality of diets
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The paleo fantasy provides a lesson in the reality of diets

Only a couple of years ago, we were peaking on paleo. The paleo diet, I mean. People were even more paleo than the Paleolithic era, understandable perhaps given that the so-called paleo diet didn’t actually exist in the Paleolithic era.

By the by. Many have already moved on. Some of the biggest paleo spruikers I know are now chewing the fat over the ketogenic diet. Some labels are even rebranding from paleo to capture shifting trends.

Paleo: a meaty topic.

Paleo: a meaty topic.Credit:PM Images

Where did it all go wrong?

The premise underpinning paleo was positive. The idea was that the discord of modern living and eating was so at odds with the way we have evolved to eat that it was causing the obesity and ill health epidemics we are currently experiencing.

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If only we could return to a healthier, more natural way of living and eating, then perhaps we could remedy some of these issues.

So they eschewed modern ag (wheat, dairy, legumes) along with sugars and fast foods in favour of meat, vegetables and nuts – the foods our ancestors apparently ate.

The only problem was there never has been a time humans lived in an entirely healthy, "natural" way.

“It's understandable that people want to feel healthier, and that they see how different diets today are from decades ago, when we didn't rely so much on highly processed foods that have a lot of sugar and salt,” says Professor Marlene Zuk, an evolutionary biologist and behavioral ecologist from the University of Minnesota.

“So they are hoping that they can feel better by starting with the most basic thing we do with our bodies, namely eating ... The notion that one can replicate how we ate many hundreds of thousands of years ago isn't well-founded, though.”

Professor Marlene Zuk.

Professor Marlene Zuk.

Peter Ungar, author of Evolution's Bite: A Story of Teeth, Diet, and Human Origins, puts it more bluntly.

“From the standpoint of paleoecology, the Paleolithic diet is a myth,” he writes. “Food choice is as much about what is available to be eaten as it is about what a species evolved to eat.”

What that means is that, depending on where we lived, the season, the weather, even the particular year, vastly different foods were available. We evolved for diversity, not meat, three veg and a side of nuts.

“Our world was ever changing, so, too, was the diet of our ancestors. Focusing on a single point in our evolution would be futile," Ungar writes.

"We're a work in progress. Hominins were spread over space, too, and those living in the forest by the river surely had a different diet from their cousins on the lake shore or the open savanna.”

Zuk, who is also the author of Paleofantasy: What Evolution Really Tells Us About Sex, Diet, and How We Live, adds that evolution is complex, so we can’t really reduce our diet or lifestyle to one singular right way.

“Evolution is the process responsible for the way life on earth appears today, whether we are humans or dandelions. But that's a much different thing than saying that evolution - or genes - dictate everything about us,” she says.

“All of our characteristics, from our height to our ability to digest dairy products to our parental behaviour, are a result of input from our genes and our environment ...

“Evolution is continuous ... we are always affected both by our genes and by the environment. Attempts to pull out one or the other – to say, for instance, that particular differences between groups are 'biological' and hence immutable - simply aren't based in science ... it's very risky – and wrong - to think of evolution as being prescriptive.”

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Though the paleo dream is but a fantasy, perhaps there are some things we can learn.

  • The past doesn’t deserve to be on a pedestal any more than the present.

“We have a lot of nostalgia for an unspecified past, when things seemed simpler, whether or not they actually were," Zuk says. "For some people, that past might be the 1950s, for others an early agrarian lifestyle, for others the Stone Age (whatever that means) ... but we just can't pick out a particular nirvana."

  • While there is no one way that we should all live, eat and move, the remedy to some of our modern maladies may be in the broader brushstrokes.
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“I'm not a dietitian,” says Zuk. “That said, there's plenty of evidence suggesting that high-calorie but low-nutrition foods contribute to obesity and related problems. And it makes sense to look at ways that our bodies are mismatched to the way environments are these days, and see if we can ameliorate that in a way that makes sense.

“For example, it seems to be bad for us to sit too much, because our bodies function better when we move. That's likely because of the circumstances in which we evolved. But that's a far cry from suggesting we should exercise in a particular way to imitate an ancestor.”

  • We may need to rethink what we have ‘evolved’ to do and what is and is not ‘natural’

“Evolution is a continuous process, with lots of compromises and tradeoffs, and that's always been the case," Zuk explains.

“Our lungs, for example, are perfectly good at getting oxygen from a terrestrial environment, but of course our ancestors were fish, so they are really compromises to a system that got oxygen out of the water. Were we more in synch when we were aquatic? Kind of. But it doesn't really help to think about when we were most in harmony, because we've always been making do with what is available.

“A famous scientist, Jacques Monod, said that evolution is 'a tinkerer, not an engineer'. He meant that living things evolve using the parts that are lying around, so to speak, like a tinkerer would build something out of bits and pieces in the garage.

"An engineer, on the other hand, would make parts designed to precisely suit the purpose, and could generate those parts from scratch. Evolution can only use what's available.”

Marlene Zuk is giving a public lecture, Paleofantasy: have humans ever lived 'naturally'? at Sydney University on November 7.