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A review by davidr
Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live by Marlene Zuk
4.0
Hundreds of thousands of people try to practice a "paleo" lifestyle, where "paleo" is short for "paleolithic", and is a euphemism for "caveman". They eat mostly meat, thinking that this is what our ancestors thrived on for tens, or even hundreds of thousands of years. They believe that humans ate this way and evolved to take advantage of this type of diet. They believe that humans have not had enough time, since the agricultural revolution, to evolve toward a more modern type of diet. Some practitioners of the paleo lifestyle take their approach much further. Some, for example, donate blood frequently, in order to mimic the results of being wounded frequently. And, some do other strange things. But they don't necessarily refuse to vaccinate themselves (although some do), in order to prevent the scourges of yesteryear, like smallpox, polio, measles, and so on. But they are not always consistent; they wear modern clothes instead of skins, they don't live in caves, and they don't use bear teeth to incur blood loss, and they wear eyeglasses.
Marlene Zuk's builds up a pretty convincing argument to back up her main premise, that humans have indeed had time to evolve significantly since the "first" agricultural revolution, about 12,000 years ago. She is an evolutionary biologist and behavioral ecologist. So, she actively does research in related fields.
Some anthropologists study isolated "primitive" tribes in order to improve understanding of prehistorical humans. But, this approach is fraught with issues. Today's isolated tribes have been influenced by modern society in many ways, and are not as isolated as many would think. They do help anthropologists to understand small-scale societies, but not earlier stages of evolution.
Evolution can be rapid. There is an interesting story about how a group of crickets in Hawaii evolved in twenty generations to suppress their singing, to be quiet, to avoid a parasitic fly. There is a similar story about an experiment that showed rapid evolution of guppies in eleven years.
The ability for some people to drink milk makes it the poster child for rapid evolution in humans. These people have developed a tolerance for lactose in milk. Lactose tolerance is an advantage in high latitudes. Lactose tolerance allows a more efficient uptake of calcium, that is otherwise prevented where sunlight is low, and vitamin D is difficult to obtain. Some societies in northern Africa have also developed lactose tolerance, which must have evolved independently from those in northern Europe. A hypothesis for this evolution is that the ability to drink milk from animals gives people a source of uncontaminated fluid, in a region where water is scarce. So, this is an example of convergent evolution, where a functionality has evolved in multiple places at multiple times, independently. Zuk remarks that one cannot refuse to drink milk in a paleo diet, because lactose tolerance depends on one's genes, and these genes have changed.
Convergent evolution also occurred in societies that lived in high altitudes. Some people in the Andes mountains have developed high hemoglobin concentrations in their blood. On the other hand, people in Tibet who live at altitudes at 13,000 feet above sea level don't have high hemoglobin levels. Instead, they have evolved faster breathing rates, in order to distribute enough oxygen to their bodies.
A central question in this book, is whether a paleo diet really is the "one and only diet that ideally fits our genetic makeup." Early humans often ate roots, tubers, and other starchy foods. Prehistoric humans and Neandertals ate grains, and sometimes cooked their food. They ate a wide variety of plants, and even made crackers! So, the suggestion that we should eat a paleo diet consisting of meat and fish, and not fruits and vegetables and grains, is plainly wrong. It is also true that the proportion of meat eaten increased about 30,000 years ago, after the invention of the bow and arrow. However, big-game hunting was an unreliable as a sole source of support for a family. I just love Zuk's comment; "Saying you want to maintain your wife and children on it is the ancestral equivalent of claiming that you will support your family by playing lead guitar in a band."
I enjoyed this book, and it seems to cover some aspects of paleolithic diet trends. But I wasn't wholly convinced by the arguments. It is very difficult to quantify how much meat vs. how much plant food was eaten in prehistoric times. The remains of plants don't fossilize, and the evidence for grains and plants in prehistoric diets is sporadic. I think that a more complete understanding will require evidence from archaeology. (By the way, I am a vegan, so I certainly do not buy the arguments to follow a paleo diet.)
Marlene Zuk's builds up a pretty convincing argument to back up her main premise, that humans have indeed had time to evolve significantly since the "first" agricultural revolution, about 12,000 years ago. She is an evolutionary biologist and behavioral ecologist. So, she actively does research in related fields.
Some anthropologists study isolated "primitive" tribes in order to improve understanding of prehistorical humans. But, this approach is fraught with issues. Today's isolated tribes have been influenced by modern society in many ways, and are not as isolated as many would think. They do help anthropologists to understand small-scale societies, but not earlier stages of evolution.
Evolution can be rapid. There is an interesting story about how a group of crickets in Hawaii evolved in twenty generations to suppress their singing, to be quiet, to avoid a parasitic fly. There is a similar story about an experiment that showed rapid evolution of guppies in eleven years.
The ability for some people to drink milk makes it the poster child for rapid evolution in humans. These people have developed a tolerance for lactose in milk. Lactose tolerance is an advantage in high latitudes. Lactose tolerance allows a more efficient uptake of calcium, that is otherwise prevented where sunlight is low, and vitamin D is difficult to obtain. Some societies in northern Africa have also developed lactose tolerance, which must have evolved independently from those in northern Europe. A hypothesis for this evolution is that the ability to drink milk from animals gives people a source of uncontaminated fluid, in a region where water is scarce. So, this is an example of convergent evolution, where a functionality has evolved in multiple places at multiple times, independently. Zuk remarks that one cannot refuse to drink milk in a paleo diet, because lactose tolerance depends on one's genes, and these genes have changed.
Convergent evolution also occurred in societies that lived in high altitudes. Some people in the Andes mountains have developed high hemoglobin concentrations in their blood. On the other hand, people in Tibet who live at altitudes at 13,000 feet above sea level don't have high hemoglobin levels. Instead, they have evolved faster breathing rates, in order to distribute enough oxygen to their bodies.
A central question in this book, is whether a paleo diet really is the "one and only diet that ideally fits our genetic makeup." Early humans often ate roots, tubers, and other starchy foods. Prehistoric humans and Neandertals ate grains, and sometimes cooked their food. They ate a wide variety of plants, and even made crackers! So, the suggestion that we should eat a paleo diet consisting of meat and fish, and not fruits and vegetables and grains, is plainly wrong. It is also true that the proportion of meat eaten increased about 30,000 years ago, after the invention of the bow and arrow. However, big-game hunting was an unreliable as a sole source of support for a family. I just love Zuk's comment; "Saying you want to maintain your wife and children on it is the ancestral equivalent of claiming that you will support your family by playing lead guitar in a band."
I enjoyed this book, and it seems to cover some aspects of paleolithic diet trends. But I wasn't wholly convinced by the arguments. It is very difficult to quantify how much meat vs. how much plant food was eaten in prehistoric times. The remains of plants don't fossilize, and the evidence for grains and plants in prehistoric diets is sporadic. I think that a more complete understanding will require evidence from archaeology. (By the way, I am a vegan, so I certainly do not buy the arguments to follow a paleo diet.)