An important
nutritional disadvantage of total specialization on crop farming
was the disappearance of meat from the peasant diet. Human energy
is supplied mainly by the carbohydrates in food, and we have seen
that the coming of agriculture meant unprecedented supplies of
carbohydrate food from the grains of cereal crops or, in some
regions, from starchy tuber crops. But man also needs proiein for
growing and maintaining the structure of his body; and for this
purpose various kinds of protein, having different combinations of
component substances called amino acids, are required in
correct balance. Animal food is a good protein source, and the
efficient Mesolithic hunters were adequately supplied. The new
large populations based on Neolithic agriculture needed to make up
their protein partly from their small herds of farm animals and
partly from crops. Protein makes up only 6-14 per cent of cereal
grains, and an exclusively cereal diet is liable to cause protein
deficiency.
A solution to this
problem came about through growing legumes. Legume grains (various
peas and beans, groundnuts, and other crops) have a protein content
of 17-25 per cent (38 per cent in the useful soy-bean of the Far
East). This high protein content is probably related to their
special capacity for obtaining nitrogen (the crucial element in
protein), which, as we have seen, comes in so useful for conserving
soil fertility, and makes them invaluable as green manures.
Moreover, cereal proteins are short of some amino acids (such as
lysine) but well supplied with others (such as methionine), while
legume proteins are rich in the former and poor in the latter. When
maize (cereal) and cow-peas (legumes) in different ratios are fed
to young rats, it is found that a 50-50 combination gives the best
protein balance; for man, too, the cereal-legume combination
provides a balanced protein diet without meat.
When cereal crop
agriculture began, it was accompanied in every continent by the
growing of legumes. Lentil beans were grown at Halicar in Turkey in
the sixth millennium b.c. They were especially common in ancient
Egypt, where lentil soup preparation is the subject of a fresco
from the reign of Rameses III (late second millennium b.c.). The
scale of lentil production in Egypt under the Romans was
impressive. When an already ancient Egyptian granite obelisk was
shipped to Rome as a souvenir for the Emperor Caligula (early first
century a.d.), tons of lentils were used as packing. Remains of
peas have been found in a Swiss Neolithic village of the fifth
millennium b.c., and broad beans in another Swiss site of the
second millennium B.C. Remains of kidney beans dating from 4000
b.c. or earlier occur in caves in Mexico, and kidney beans, lima
beans, and a jar of ground-nuts have been found in Peruvian tombs.
Manuals on how to grow soy- beans were among the earliest Chinese
books (second millennium b.c.).
In due course, all these crops were spread far and
wide, and lentils, broad beans, and kidney beans are now almost
world-wide.
It seems to have been realized very early that
legumes were a food substitute for meat. The first recorded
nutritional experiment is described, with admirable scientific
precision, in the Book of Daniel. At the end of the seventh century
b.c., Nebuchadnezzar, the Chaldean king of Iraq, sacked Jerusalem
and carried off most of the Hebrew upper classes to Babylon. The
most promising children he decided to bring up in his palace, to be
trained into competent Babylonian bureaucrats. He instructed his
chief eunuch, Ashpenaz, to feed them for three years from the royal
table, after which he intended to inspect their health and
educational progress. Among these young students was the prophet
Daniel. He realized that the planned diet would include meat that
was not kosher (not permitted by the laws of Moses, because not
prepared in the Hebrew way); and he asked Ashpenaz, who liked him,
if the Hebrew children could be excused. The official objected that
if they did not eat the fine nutritious meats they would be less
healthy-looking than the other palace children by the time of the
king's inspection: "Then shall ye make me endanger
my head to the king." The
intelligent young Hebrew persuaded Melzar, a subordinate eunuch in
charge of catering, to let the Hebrew children live on beans and
water for ten days, and observe the result. "And at the end of ten
days, their countenances appeared fairer and fatter in flesh than
all the children which did eat the portion of the king's meat." So
Daniel and his friends were allowed to stick to their leguminous
diet.
The royal
table of Babylon was certainly supplied with plenty of meat. On
account of its scarcity, what meat there was in the hydraulic
societies found its way to the larders of the king and the top
officials of the bureaucracy. Meat became, and has remained, one of
the most universal status symbols in human civilization. In later
history influenced by Europe, meat became associated with wealth in
money. The Greeks (in the fifth century b.c.) described a new-rich
self-made man thus: "now he doesn't like lentils any more." An FAO
survey made in a.d. 1964 shows that meat goes with higher incomes
today, not only as between individuals but also as between the more
and less developed nations (see map). The average New Zealander
gets 2-| ounces of actual animal protein per day, the average
Indian j ounce. In the U.S.A., animal protein makes up 70
per cent of all the protein in the nation's diet; in India it makes
up only 12 per cent. Peasants of the dry belt, today as for so many
millennia in the past, must make up most or all of their protein
from cereal and legume crops.
