Table of Contents
The Story of the Human Body by Daniel E. Lieberman is about how our bodies have evolved across time, how the environment and culture affected our development, and what, if any kind of behavior or lifestyle, is considered optimal for human beings.
A Return to the Past
Some have called for a return to the Paleolithic lifestyle, since it is healthier than our modern world, where people lounge in chairs all day long and eat domesticated plants and animals, and drink coffee.
But the short answer is that there is no ideal environment for the human body. For example, short legs helped humans conserve heat in cold climates but is disadvantageous to running or walking long distances efficiently. Natural selection rarely achieves perfection because no environment is the same.
Evolutionary Medicine
The emerging and important new field of evolutionary medicine proposes that we have created an environment that is not well matched for our bodies. While farming led to more food and modern sanitation and medicine led to less infant mortality and increased longevity, there have been many cultural changes that have changed the interactions between our genes and environments in detrimental ways.
These diseases are mismatch diseases, defined as diseases that result from our Paleolithic bodies being poorly adapted to modern behaviors.
Germs
Most people think germs are invisible pests that cause disease. The less of them, the better. We disinfect our homes, food, and bodies with a collection of germ-killing weapons, including soap, bleach, and antibiotics. No one questions the assumption that cleaner is healthier. And for good reason. Sanitation and antibiotics has saved more lives than any advancement in medicine.
But from an evolutionary perspective, our sterilizing behavior is abnormal and potentially harmful. One reason is that your body is host to a microbiome: trillions of other organisms that live in your gut, skin, and respiratory tract. Some estimates say that there are ten times as many foreign microbes in your body than your own cells.
The Future
Even though the human body has come a long way, the journey is far from over. What will the future look like? Will our technologies cure cancer, solve the obesity epidemic, and make people healthier and happier? Or are we headed towards a dystopia as described in WALL-E, where people are chronically ill weaklings who depend on medicine, machines, and big corporations to survive?
How can an evolutionary perspective help us make better decisions? There is no single answer, but here are some.