During the early Roman period the food that was most used was cereal grain in the form of a kind of porridge made from cooked cereals, which overall may have accounted for as much as seventy percent of the populations caloric needs. Early in the Roman period as well as in the Greek world, barley was favored because it was plentiful and relatively inexpensive. This barley porridge was often supplemented with dairy products, olives, vegetables, and perhaps fresh fruit. Less often the
porridge would be served with meat or fish. This preference seemed, with the Romans, to change to predominantly more wheat and less barley.
By the second century B.C.E. wheat was favored in Italy as a human foodstuff and barley was used to feed livestock except in times of shortage. Originally "far" (husked wheat) was prepared as the staple
"puls" (porridge) of the day. Later the development of "frumentum" (a species of naked wheat) was made into bread. Bread was sometimes flavored
with other foods such as honey or cheese. This bread was eaten at most meals and formed a staple food throughout the Republic, and later the Empire, by those who were not wealthy and were the Roman working class, unemployed or slaves. By the end of the first century B.C.E. grain stores were being developed by Rome. Wheat was harvested in the Po River valley and about thirty percent of the grain supply was brought in from the Nile valley in Egypt and other areas of wheat producing farms in North Africa.
Some consumption figures on the quantities of grain needed to feed the burgeoning population of Rome are quite interesting. From antiquity we get the information that an average wheat yield was approximately between seven and one-half to twenty-two and one-half bushels per acre (5 to 15
quintals per hectare), which ranks as about one-third of present-day grain yield. Since each individual used nearly 440 pounds (200 kg) of grain a year, and since population in the Roman Republic is estimated to have been nearly 750,000 people by the first century B.C.E., this means that the overall grain requirements for the Roman world was between 110,000 to 230,000 tons of wheat per year.

It is not surprising then that grain was brought in not only from fairly close areas such as Etruria, Umbria, and Campania, but from much farther afield as well, as from Sicily, Sardinia, North Africa, and Egypt.
This constant problem of providing large amounts of grain was finally resolved by the development of a "grain dole" in which it is estimated that by 46 B.C.E. in excess of 300,000 people in the city of Rome alone may have been collecting free grain. These were the poor, the unemployed, and the elderly. In following years oil and even wine were
added to this dole to extend this public assistance program. This munificence then became a kind of welfare state, and was for the most part politically motivated. During the Roman Republican period, those who stood for a magistracy depended upon the people for their votes, and therefore it was wise to keep the people happy. Providing food was a way
of ensuring that. Later on during the Empire when elections were not so important, food was distributed to accumulate personal support among the population, as well as to maintain the peace.

(to be continued)

References:

• Atkins, L., and R. Atkins, "Handbook to Life in Ancient Rome"
  
• Fass, P., "Around the Roman Table"
  
• Bethel, Don R., "Foodstuffs, Cooking and Drugs," in Civilization of the Ancient Mediterranean - Greece and Rome," M. Grant and R. Kitzinger, Eds.