The
characteristics that most distinguish humans from other primates are largely
the results of natural selection acting to improve the quality of the human
diet and the efficiency with which our ancestors obtained food. Some scientists
have proposed that many of the health problems modern societies face are consequences
of a discrepancy between what we eat and what our Paleolithic forebears ate.
Yet studies of traditionally living populations show that modern humans are
able to meet their nutritional needs using a wide variety of dietary strategies.
We have evolved to be flexible eaters. The health concerns of the industrial
world, where calorie-packed foods are readily available, stem not from deviations
from a specific diet but from an imbalance between the energy we consume and
the energy we expend.