"The hallmark of the human diet is flexibility, the ability to
find or make a meal in any environment," says anthropologist
William Leonard of Northwestern University. He cites evidence
for a variety of diet in different places, noting that animal
herders in Siberia get more than half of their food from meat,
while meat makes up only 5 percent to 6 percent of the diet of
potato farmers in Peru. High nutrition diets became necessary
for humans to meet the increasing energy demands of the large
brain, and the hunting-gathering lifestyle developed as humans
took advantage of grazing animals such as antelope and gazelle.
The staple foods of humans are much more nutritionally dense
than those of other large primates, which can subsist on leaves
and fruit, he said. The size and shape of the jaw and wear on
the teeth can tell us a lot about what ancient people ate, said
Peter Ungar of the University of Arkansas. Yet it can sometimes
be misleading. For example, one skull with large, flat teeth was
thought to indicate