Tasty by John McQuaid Read Free Book Online

of silica from the soil that plants absorb and distribute through their cells. When the plant matter rots away, the silica remains, providing an identifiable afterimage of the cells.)
    Henry expected that the pair had lived on a savanna diet, heavy on grasses and roots, consistent with the environment in which they lived. But when she analyzed some of the tartarfrom their teeth, she was surprised. The Australopithecus sediba diet came almost entirely from the shrinking forests, which contained a different carbon isotope than savanna roughage: nuts with hard shells, broad leaves pulled from bushes and reedy trees growing low under the forest canopy, bark stripped off the younger trees and chewed like prehistoric jerky. Sometimes they would have eaten fruit, but such finds would have been rare. Bitter, leafy, herbal flavors were the highlights of eating.
    It was a taste mystery. They could strike out across the savanna anytime it suited them. In order to keep eating their forest-based diet, they would have had to travel far, moving across grasslands, ignoring the food they offered. This diet was, on some level, a choice. Perhaps the flavors and textures of savanna foods repelled them. Did other groups behave differently? Did this group later change its behavior, or die when its favored foods ran out? It’s sad to think of this species employing its emerging intelligence on a quest to keep eating a familiar but increasingly spartan diet, seemingly ignoring one key to its survival.
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    Shifting habitats forced human evolution onto an improbable path. Food sources grew unreliable and farther apart, so bodies became more upright, lean, and mobile. Brains grew larger to devise more sophisticated strategies for getting food. But these two trends conflict.
    Compared to that of our closest relatives, chimpanzees, the human body is an improbably fragile vessel. Chimps have big guts and large, powerful jaws, and can open their mouths twice as wide as we can. Smaller human jaws and faces are traced to a 2.4-million-year-old mutation in a gene that makesmyosin, a muscle protein, and produces weaker, finer muscles. The human gut is also small. Yet our brains are large, and demanding. An adult human brain consumes about a quarter of the body’s energy. In other primates, it’s only a tenth. On paper, this anatomy looks like a recipe for disaster. Chimps must spend many hours of each day chewing to sustain themselves. How did our ancestors ever eat enough to survive?
    The Homo sapiens body works for one principal reason: bigger brains helped humans create better, tastier food. Our ancestors made up for their physical weaknesses by becoming skilled hunters and chefs.
    In the 1930s, the legendary anthropologists Louis and Mary Leakey excavated a trove of fossils in Kenya’s Olduvai Gorge that illustrated this progression over two million years. The earliest tools, from the time of the australopithecines and before, had been fished from the smooth quartz and basalt of the Omo River cobble and smashed and cracked to produce a flat surface that could be used for pounding. As time went on and more sophisticated species appeared, a craft developed: rocks were chipped away to create a characteristic spade-like shape of concave impressions and edges. Such a tool could be used for chopping and scraping. The most obvious use for such implements was butchering animals, and excavators also found stone tools and animal bones marked by cuts and hammer blows.
    Meat became a dietary staple for members of our own genus, Homo . This changed eating forever. Unlike industrially produced meats, which are succulent and fatty, wild game is exceedingly tough. Cutting and tenderizing made it possible to eat more game. Starchy roots, another important staple, could be sliced or mashed. In other words, food was partially digested before the first bite was taken. Now constant chewing was no longer necessary, and meals were briefer