"The Problem With the Paleo Diet Argument"
Our epidemics of dietary disease have prompted a great deal of research
into what humans are meant to eat for optimal health.
In 1985, an influential article was published proposing that
our chronic diseases stem from a disconnect
between what our bodies evolved eating during the stone age
during the last 2 million years and what we’re stuffing our face with today,
advocating for a return towards a hunter-gatherer type diet
of lean meat, fruits, vegetables, and nuts.
Though it may be reasonable to assume
our nutritional requirements were established in the prehistoric past,
the question of which prehistoric past remains. Why just the last 2 million?
We’ve been evolving for 25 million years
since our common great ape ancestor
during which our nutrient requirements and digestive physiology were set down,
and therefore probably little affected by our hunter-gatherer days at the tail end.
So what were we eating for the first 90% of our evolution?
What the rest of the great apes ended up eating -
95 plus percent plants.
This may explain why we’re so susceptible to heart disease.
For most of human evolution, cholesterol may have been virtually absent from the diet.
No bacon, butter, trans fats, and massive amounts of fiber,
which pulls cholesterol from the body.
Now this could have been problem since our body needs a certain amount of cholesterol,
so our bodies didn’t just evolve to make cholesterol,
but to preserve it, recycle it;
our bodies evolved to hold on to cholesterol.
And so if you think of the human body as a cholesterol conserving machine
and plop it into the modern world of bacon/eggs/cheese/chicken/pork/pastry,
well then no wonder artery-clogging heart disease is our #1 cause of death.
What used to be so adaptive for 90% of our evolution,
holding on to cholesterol at all costs since we aren't getting much in our diet,
is today maladaptive, a liability leading to the clogging of our arteries.
It seems our bodies just can’t handle it.
As the editor-in-chief of the American Journal of Cardiology noted 25 years ago,
no matter how much fat and cholesterol carnivores eat,
they do not develop atherosclerosis.
You can feed a dog 500 eggs worth of cholesterol and a stick of butter
and they just wag their tail;
their bodies, evolved from wolves, are used to getting, eating, and getting rid of excess cholesterol,
whereas within months, a fraction of that cholesterol
can start clogging the arteries of animals adapted to eating a more plant-based diet.
Even if our bodies were designed through natural selection
to eat mostly fruit, greens, and seeds for 90% of our evolution,
why didn’t we better adapt to meat-eating in the last 10%, during the Paleolithic?
We’ve had nearly 2 million years to get used to all that extra saturated fat and cholesterol.
If a lifetime of eating like that clogs up nearly everyone’s arteries,
why didn’t the genes of those that got heart attacks die off
and get replaced by those that could live to a ripe old age
with clean arteries regardless of what they ate?
Because most didn’t survive into old age,
they didn’t live long enough to get heart attacks.
When the average life expectancy is 25,
then the genes that get passed on are those
that can just live to reproductive age by any means necessary,
and that means not dying of starvation.
And so the higher the calorie foods, the better.
So eating lots of bone marrow and brains, human or otherwise,
would be a selective advantage,
as would discovering a time machine stash of Twinkies for that matter.
If we just have to live long enough to get our kids to puberty to pass along our genes,
then we don’t have to evolve any protections against the ravages of chronic disease.
To find a population nearly free of chronic disease in old age,
we don’t have to go back a million years.
In the 20th century, networks of missionary hospitals in rural Africa
found coronary artery disease virtually absent, and not just heart disease,
but high blood pressure, stroke, diabetes, common cancers, and on down the list.
In a sense, these populations in rural China and Africa
were eating the type of diet we’ve been eating for 90% of our last 20 or so million years,
a diet almost exclusively of plant foods.
How do we know it was their diet that protected them and not something else?
In the 25 year update to their original paleo paper,
they tried to clarify that they did not then and do not now
propose that people adopt a particular diet
just based on what our ancient ancestors ate.
Dietary recommendations must be put to the test.
That’s why the pioneering research from Pritikin, Ornish, and Esselstyn
is so important, showing that plant-based diets can not only stop heart disease
but have been proven to reverse it in the majority of patients.
Indeed, it’s the only diet that ever has.
Perhaps because that's what we ate throughout the vast majority of our evolution.