Alice Friedemann’s review of: Marlene Zuk. 2013. Paleofantasy: What Evolution really tells us about sex, diet, and how we live.
My first introduction to Evolutionary Psychology was “The Adapted Mind” which posited we’re unhappy because of the tremendous difference between the modern world and the natural world we’d lived in for millions of years. This idea was especially appealing because I love being outdoors and learning natural history. It made sense.
But now I’m going to have to give up blaming the ancestral environment for my problems, because it appears we’ve been evolving fast enough to cope with our modern diet and lifestyle.
We can now quickly compare our DNA with ancient skeletons and see that it doesn’t take thousands of years to evolve – many adaptations, like the ability to digest milk as an adult, took place recently within just a few generations. Some other genes that have rapidly evolved are:
- Ability to digest starch by having more copies of the amylase gene
- Polar people have genes to deal with cold stress
- Foragers are adapted to a wider variety of foods than agricultural people
- Cultures that eat mainly plants have more liver enzymes to detoxify compounds found in roots and tubers than hunting cultures that depend mainly on meat
But word hasn’t gotten out to the people following the Paleo Diet and Lifestyle. Some of their misguided notions are no doubt driven by nostalgia for a simpler past. Nearly all times and places have had legends of a “Golden Age” and more recently, visions of Noble Savages living in harmony with nature (sadly, not true, as you can read in Shepard Krech’s “The Ecological Indian: Myth and History”).
Paleofantasists shun anything cavemen didn’t eat. So kiss refined sugar, dairy, legumes, and grains good-bye. Embrace Meat, Fruit, and Vegetables.
The biggest bugaboo is eating starch, but there is a lot of archeological evidence and common sense that hunter gatherers ate starch, such as:
- I’ve read a great deal about the native tribes of California, and in many, half of their diet was acorns, which are 5% carbohydrate (whole wheat and corn flour are 7%). The Mayans and Inca ate corn, as well as potatoes, squash, beans, quinoa and many other carbohydrates.
- Bits of starch grains have been found on the grinding stones from 30,000 year old sites in Italy, Russia, and the Czech Republic, where our ancestors made flour from ground up plants, combined it with water and made a pita bread on stones heated in fires.
- Fossil hominids had such sturdy premolar teeth it’s believed they were probably used to open seeds and chew starchy underground tubers and bulbs.
- Anthropologist Frank Marlowe studied the eating patterns of 478 groups around the globe. He found that no matter where you live, at least a third of your diet is going to come from plants (and in many places nearly all of your diet), so the idea our ancestors were mainly carnivorous is not true.
- Even Neanderthals ate starch, which we know from studying the plaque on their teeth.
- Scientists analyzed the DNA of human populations that had low or high starch consumption. It turns out that cultures that eat a lot of starch have more amylase genes (and therefore more amylase) with which to process and consume starches. Our closest relatives, chimpanzees, eat very little starch, and have 1/6 to 1/8 of the amylase humans do.
- Zuk says “So early humans ate crackers. What’s the big deal?” Our ancestors were smart to grind roots so the flour could be stored or carried, since often game animals were seasonal and no meat was to be had many times of the year. But word hasn’t gotten out to cavemanforum.com and other such websites, where meat reigns supreme, and carbohydrates are the ultimate evil.
The problems with this the Paleofantasy are many, here are just a few:
- The idea we ever perfectly adapted to an environment is false, the environment kept changing (there are theories even that we became as intelligent as we are trying to cope with the rapidly changing environment, which has never been as stable as the past 10,000 years).
- Did cave men exhausted from chasing animals down long for the days when humans stole kills away from lions instead?
- How can you choose a paleodiet when nearly every tribe ate different kinds of food? There’s no such thing as a “natural” diet, we ate way too many different kinds of food in the past and have adapted to too many new ones.
- Where can you find meat as lean as in the past not from domesticated animals bred to grow quickly with more fat and fed anti-biotics? Similarly, fruits and vegetables are not remotely like the original varieties. Potatoes were bitter lumpy roots, apples in Kazakhstan so bitter they’re barely edible.
- One of the biggest forbidden foods of Paleo enthusiasts is starch, but we now know from above that our distant ancestors ate a great deal of starch – seeds, roots, tubers, acorns, and so on.
- Milk is considered an evil in many paleo-diets, but about 35% of the world’s people can digest milk and dairy products – this ability to digest lactase arose three times in different genetic ways within 3 civilizations and spread throughout the population rapidly because it was such a huge advantage, those with this mutation had more surviving children. And not just because of getting calcium and enough calories – milk is a safer liquid than the feces-polluted water near villages, the resulting diarrhea from bad water was what caused such high mortality in children under 5. Even those without this ability can still usually eat some dairy, especially fermented cheese products such as yogurt.
- The latest research in gut microbes shows that our gut flora have evolved with us to help us digest new kinds of food, yet another avenue to adapt rapidly to new environments. As our diets change, it appears that our internal microbes do too.
Some of the funniest parts of the book are when Zuk reports on the Paleofantasies she’s found in books, newspapers, or on the internet, such as the one about rock star Ozzy Osbourne attributing his survival of past excesses like drinking 4 bottles of Cognac a day to his Neanderthal genes.
Many people see agriculture as where we went wrong, and long to go back to the hunter-gatherer days, when we had a much wider diet, probably eating about 50 to 100 kinds of plants. Now we use a mere 30 crops for 95% of our plant-based foods, 50% of them corn, rice, and wheat.
Another reason agriculture is seen as a wrong turn is that it takes so much more work than hunting and gathering. Zuk shows that this may not be true, the skills of hunting take a long time to develop. Men aren’t at their peak hunting skills until they’re 35 and woman are best at foraging when they’re between 35 and 45. Hunting and gathering was no bed of roses, and Zuk explains why it was not as idyllic as people imagine it to be (as well as why agriculture has advantages and benefits over hunter-gatherer societies).
Agriculture is also seen as evil because that’s when diseases gained ground, because there were large populations and infectious disease could spread more easily. And due to less variety in foods, nutrients were often missing, leading to new vitamin deficiency diseases such as pellagra, anemia, and scurvy
What many people don’t realize is that this changed. About 4,000 years ago, skeletons from Egypt show that people regained their height, and only 20% showed any signs of malnutrition.
In addition, the more people you have, the more likely there will be good mutations for evolution to work with. The population increased so much that a good mutation which might occur every 100,000 years would now turn up every 400 years. Favorable mutations spread faster in larger populations, speeding up evolution. Scientists have calculated there have been almost 3,000 new adaptive mutations in the last 50,000 years in Europeans alone.
Gregory Cochran, in “The 10,000 Year Explosion. How Civilization Accelerated Human Evolution” estimates that our evolution has sped up 100 times faster in the past 10,000 years than the previous 6 million years, and that even people 4,000 years ago were both genetically and culturally different from us.
Andrew Hendry believes that rapid evolution may be the norm and not the exception.
So sure, agriculture had its drawbacks, but it has positive aspects as well. Our intelligence increased dramatically and in turn led to greater cultural and technological complexity.
Paleofantasies and evolutionary psychology stories can be wishful thinking and rationalizing. People have constructed stories to justify being unfaithful or eating junk food for example. Though it turns out that the actual amount of infidelity in America, based on DNA paternity tests, was much lower than I’d expected. It’s only between 1 and 3.7% — not the 10% or more I’d read elsewhere. I trust the data these lower figures come from – genetic testing for diseases to find out which parents have the genetic disorder rather than the figures from men who suspect they aren’t the father and get tested, which skews the number much higher than it actually is.
Of course, our love of junk food may be based on the adaptive craving we have for sugar, since way back when that mainly came from ripe fruit, which was very nutritious and uncommon.
Too bad we don’t also crave fiber – hunter gatherers typically ate 100 grams a day, but now the USDA daily standard is only 25 grams, and most of us don’t even get that. The average American only eats 20 grams of fiber a day.
David Kessler, in “The End of Overeating. Taking control of the insatiable American appetite”, calls the processed and restaurant food we eat “adult baby food”, because you can woof it down in 10 bites on average. Food used to take about 25 chews per bite before you could swallow. Chewing takes time and gives your body a chance let you know you’re full.
Kessler says that the reason it only takes 10 bites is because so much fiber, gristle, and bran has been removed. Meat is “pre-chewed” in marinades. If the food industry could fill you up like a car at a gas station, they would, but what’s saving us is that we don’t want to drink our doughnuts.
As you’ll see if you look at site wholegrainalice, bread is called the staff of life because for millennia that was the main source of calories for people in many civilizations. A pound of whole grain wheat flour has 54.4 grams of fiber, over twice your daily requirement, and 5 times more fiber than a pound of white flour, which only has 11.2 grams of fiber (you need 25 grams a day). It ought to be a crime for flour manufacturers to strip the bran and germ out of wheat, where nearly all the fiber, vitamins, minerals, and essential healthy fats are. I think the gluten-free diet is really stupid nutrition-wise, but if it’s your only way to avoid white flour and get more whole grains into your diet, then go for it. It’s hard to find ways around the predatory industrial food system, which cares only about profits, unless you cook from scratch at home (i.e. no packaged foods). The food industry is about as unpatriotic as you can get – processed food is a good part of why Americans are unhealthy and living less long than the previous generations, and driving our health care costs so high we’ll go bankrupt, unless the corrupt financial industry does that first.
The first book to promote paleofantasies was Walter Voegtlin’s 1975 “The Stone Age Diet”. This was when the idea we should be eating a lot more meat like the cavemen did became popular.
Zuk mentions the 2011 U.S. News & World report evaluation of 20 diets, in which the Paleo diet came in dead last. There were 22 experts – mainly physicians and professors of food science and nutrition, who evaluated and ranked a variety of diet plans based on
how easy to follow, ability to produce short and long-term weight loss, nutritional completeness, safety, and prevent diabetes and heart disease.
In the 2013 evaluation of 29 diets, the Paleo diet came in last again. Here are the scores of the diets from best to worst (on a scale of 5)
3.7 Jenny Craig
The Paleo diet scored low because dairy and grains have a lot of nutrients, and unless the meat is lean, the fat can give you heart disease. There are far less carbohydrates than what’s recommended, about 23% rather than the 45-65% of your calories coming from carbohydrates that the USDA recommends. You’re also not getting enough calcium and Vitamin D if you aren’t in the sun enough. Read the review for all the details.
Lately studies have shown that sitting and inactivity too much of the day is one of the biggest causes of obesity and early death. I’ve got a kitchen timer at my desk that goes off every 20 minutes to get me up for a few jumping jacks now, since apparently even working out at the gym doesn’t do any good if you sit for too long. But it wasn’t until reading this book that I found an explanation of why sitting might be so bad for you.
Zuk writes that it’s possible the genes that metabolize glucose behave different in your body depending on whether you’re active or sedentary. “A couch potato body sends the wrong signals to the genes, which behave as if a famine were imminent, since inactivity is historically associated with not having any food”, which tends to make your body use calories frugally and gain weight, plus the lack of exercise leads to hypertension, atherosclerosis, Alzheimer’s and a host of other diseases.
I also found it interesting that many women anthropologists have questioned the macho perspective of their male colleagues who promoted the idea of “Man the Hunter”. It turns out that it’s quite likely that women hunted as well. Adrienne Zihlman says that the old idea of “Man the Hunter came to stand for a way of life that placed males center-stage, gave an evolutionary basis for aggressive male behavior and justified gun use, political aggression, and a circumscribed relationship between women and men as a ‘natural’ outcome of human evolutionary history.”
In fact, the main function of hunting might not be subsistence at all, since hunting is often unsuccessful, and when it is successful, the meat is typically shared between many families, so a good hunter isn’t always increasing the survival of his own children. Or put another way, big-game hunting is as unreliable as counting on earning your living as a rock star or gambler. It’s thought by some anthropologists that the purpose of being a good hunter is a way to gain status and the respect of other people more than a way to provide calories.
Another assumption that I had about childhood – it’s longevity being due to the need to learn, may also not be true. It’s possible that a long childhood is good for the parents, since children work hard in most societies, at such tasks as gardening, caring for animals, taking care of younger siblings, and aren’t paid to do these chores. Children are also inexpensive to feed and at some point do enough labor to more than compensate for what they eat. It turns out that many social, hunting, and gathering skills are learned after childhood, so a long childhood to learn skills is probably not the main reason childhood lasts so long.
Hillary Clinton famously said that it takes a village to raise a child. She had no idea how right she was, it turns out that we are what scientists call “cooperative breeders”. Which means that we go way beyond most mammals, where just the mom and sometimes the dad help out with the young. There are only a few species where individuals other than the parents help raise the young. Usually they’re older brothers and sisters. Some examples are meerkats and about 8% of bird species. In humans, you can see this in that many people besides the parents handle and play with babies and children. Zuk says she isn’t suggesting a paleo-Kibbutz where we all share the children, but in many societies, half the care is by done by other relatives and unrelated group members. Studies of Israeli and Dutch children showed they did best when they had at least 3 relationships with adults where there was a clear message of “you will be cared for no matter what.”
Clearly that isn’t happening in America, one of the few countries were babies don’t sleep in bed with their mothers and in many other ways are raised in unnatural ways that cause our babies cry longer and louder than babies in other cultures.
Zuk has a great sense of humor and although I’ve read a lot of what’s in the book, there were enough surprises and the writing was far more entertaining than most non-fiction on any topic, that you will probably enjoy this book as well.