Free Cooked: A Natural History of Transformation by Michael Pollan Page B

at
around 790,000 B.C., but Wrangham’s hypothesis suggests cooking must have begun at
least a million years earlier. In his defense, Wrangham pointed out that evidence of
fires that old would be unlikely to survive. Also, cooking meat doesn’t
necessarily leave behind charred bones. But recently archaeologists found a hearth in a
cave in South Africa that pushed the likely date for cooking back considerably
further, * to one million years B.C ., and the hunt for even
older cook fires is on.
    So far at least, Wrangham’s most
convincing arguments are deductive ones. Some new factor of natural selection changed
the course of primate evolution about two million years ago, expanding the brain and
shrinking the gut; the most plausible candidate for this new selective pressure is the
availability of a new, higher-quality diet. Meat by itself could not have supplied that
diet. Primates, unlike dogs, don’t digest raw flesh efficiently enough to thrive
on it. The only diet that could have yielded such a dramatic increase in energy is
cooked food. “We are,” he concludes, “cooks more than
carnivores.”
    To demonstrate how the advent of cooking
could have supplied a caloric boon sufficient to change the course of our evolution,
Wrangham cites several animal-feeding studies comparing raw and cooked or otherwise
processed food. When researchers switch a python’s diet from raw beef to cooked
hamburger, the snake’s “metabolic cost of digestion” is reduced by
nearly 25 percent, leaving the animal that much more energy to put to other purposes.
Mice grow faster andfatter on a diet of cooked meat than on a diet of
the same meat raw. * This might explain why our pets
tend toward obesity, since most modern pet food is cooked.
    It would seem that all calories are not
created equal, or, as a proverb quoted by Jean Anthelme Brillat-Savarin in
The
Physiology of Taste
puts it, “A man does not live on what he eats, an old
proverb says, but on what he digests.” Cooking allows us to digest more of what we
eat, and to use less energy doing it. † What is curious is that animals
seem instinctively to know this: Given the choice, many animals will opt for cooked food
over raw. This shouldn’t surprise us: “Cooked food is better than
raw,” Wrangham says, “because life is mostly concerned with
energy”—and cooked food yields more energy.
    It may well be that animals are
“pre-adapted” to prefer the smells, tastes, and textures of cooked food,
having evolved various sensory apparatus to steer them toward the richest sources of
energy. Attractive qualities such as sweetness, softness, tenderness, and oiliness all
signify abundant, easy-to-digest calories. A hardwired preference for high-energy foods
would explain why our evolutionary ancestors would immediately have appreciated cooked
foods. In speculating as to exactly how early humans would have discovered all the good
things fire does to food, Wrangham points out that many animals scavenge burned
landscapes, enjoying particularly the roasted rodents and seeds. He cites the example of
chimpanzees in Senegal, who will eat the seeds of the
Afzelia
tree only after a
fire has passed through and toasted them. It seems likely that our ancestors would also
have scavenged among the remains of forest fires, looking for tasty morsels and, perhaps
occasionally, getting lucky enough to have the sort oftransformative
experience that Bo-bo, the swineherd’s son in Charles Lamb’s story, did when
he first touched that bit of crackling to his tongue.
    Like any such theory—indeed, like evolution
itself—the cooking hypothesis is not subject to absolute scientific proof. For that
reason, some will no doubt dismiss it as another “just so” story, Prometheus
in modern scientific garb. But, really, how much more can we expect when trying to
account for something like the advent of ourselves? What the cooking hypothesis gives us
is
a compelling modern myth—one cast in the language of