The Story of the Human Body summary

What sets us apart from the rest of the animal kingdom – is it, for example, our large brains or perhaps our unique opposable thumbs?

Actually, it’s our posture!

Let’s stick with chimpanzees a little longer. The average chimp spends about half of its waking hours chewing. That’s partly because of the things they eat. Palm fruits, wild figs and grapes are all firm favorites. But they’re not like the fruits we see when we go grocery shopping. They’re much less sweet and a good deal more fibrous.

That means eating is hard work. In fact, if a chimp wants to make sure it’s getting enough to eat, it has to consume about a kilogram of food every hour and spend the next two hours digesting!

How far back in time would we have to travel to meet a recognizably human ancestor?

Well, around 1.9 million years ago, Homo erectus walked the earth. This species of archaic humans spread rapidly across Africa and Eurasia. Its success was down to the lifestyle it invented. It was the first hunter-gatherer.

The hunter-gatherer lifestyle opened up new and better food sources for our early ancestors. That allowed them to spread far and wide from their original stomping grounds in Central Africa. Having gradually dispersed northward, they reached the Caucasus Mountains around 1.8 million years ago.

Access to extra calories changed their bodies profoundly and humans developed larger brains. That was just as well. The Ice Age which had begun around 2.6 million years ago would be around for a while yet – in fact, it only ended 11,700 years ago! It was a tough time presenting plenty of conundrums. Extra gray cells didn’t go amiss.

Modern man, Homo sapiens, emerged in sub-Saharan Africa around 200,000 years ago. The species spread quickly. By around 30,000 years ago, modern humans were living on every continent.

Humanity can trace its ancestry back to a very small group. The population of Homo sapiens from which we are descended as a species was made up of just 14,000 individuals. For non-Africans, that’s even smaller: they have just 3,000 common ancestors!

The American ecologist Jared Diamond called agriculture the “worst mistake in the history of the human race.” Abandoning the hunter-gatherer lifestyle and settling down to farm the land wasn’t exactly an advantage for our ancestors. Agriculture is a backbreaking pursuit, and the diet of farmers was much worse than that of their free-ranging forefathers.

So why did it catch on? Well, farming does have its upsides. Most importantly, it provides a growing population with a reliable source of sustenance.

The Industrial Revolution was kickstarted by the invention of machines capable of mass-producing various goods. It first took root in eighteenth-century England. It’s been slowly spreading across the face of the earth ever since.

Before the advent of the industrial age, the world’s population was around one billion. Now there are seven billion people on earth, most of them living in cities. The planet hasn’t been the same since.

The human body is the product of millions of years of slow evolution. But time has started moving too quickly for us since the Industrial Revolution. Our bodies are struggling to keep pace with the speed of social change.

That’s given rise to so-called mismatch diseases. These are caused by the conflict between modern life and our prehistoric bodies.

When astronauts return from space, they must be carried to keep their leg bones from snapping under the strain of walking. That’s an extreme example of an everyday truth: if we don’t use something enough, we start losing our ability to use it all.

Physical exercise is incredibly important for this reason.

Modern society has created environments which just don’t suit our bodies. Because we’re mismatched with the world around us, we develop mismatch diseases like type 2 diabetes and osteoporosis.

So it’s hardly surprising that around 20 percent of the GDP of the United States is spent on healthcare. But offense is better than defense. Around 70 percent of all illnesses could be prevented if we all exercised more regularly and ate more healthily.