There are many references to food and drink in early Irish literature. Honey seems to have been widely eaten and used in the making of mead. The old stories also contain many references to banquets, although these may well be greatly exaggerated and provide little insight into everyday diets. There are also many references to fulacht fiadh. These were sites for cooking deer, and consisted of holes in the ground which were filled with water. The meat was placed in the water and cooked by the introduction of hot stones. Many fulacht fiadh sites have been identified across the island of Ireland, and some of them appear to have been in use up to the 17th century.
Excavations at the Viking settlement in the Wood Quay area of Dublin have produced a significant amount of information on the diet of the inhabitants of the town. The main meats eaten were cattle, sheep and pigs. Poultry and wild goose|geese as well as fish and shellfish were also common, as were a wide range of native berries and nuts, especially hazel. The seeds of knotgrass and goosefoot were widely present and may have been used to make a porridge.
From the Middle Ages, until the arrival of the potato in the 16th century, the dominant feature of the rural economy was the herding of cattle. The meat produced was mostly the preserve of the gentry and nobility. The poor generally made do with milk, butter, cheese, and offal, supplemented with oats and barley. The practice of bleeding cattle and mixing the blood with milk and butter (not unlike the practice of the Maasai) was not uncommon. Black pudding was made from blood, grain, (usually barley) and seasoning remains a breakfast staple in Ireland.
Potatoes form the basis for many traditional Irish dishes The potato was introduced into Ireland in the second half of the 16th century, initially as a garden crop. It eventually came to be the main food crop of the poor. As a food source, the potato is extremely valuable in terms of the amount of energy produced per unit area of crop. The potato is also a good source of many vitamins and minerals, particularly vitamin C (especially when fresh).
Potatoes were cultivated by much of the populace at a subsistence level and the diet of this period consisted mainly of potatoes supplemented with buttermilk. Potatoes were also used as a food for pigs that were fattened-up and slaughtered at the approach of the cold winter months. Much of the slaughtered pork would have been Curing (food preservation)cured to provide ham and bacon that could be stored over the winter.
Fresh meat was generally considered a luxury except for the most affluent until the late 19th century and chickens were not raised on a large scale until the emergence of town grocers in the 1880s allowed people to exchange surplus goods, like eggs, and for the first time purchase a variety food items to diversify their diet.
Continue to read this very fascinating history at : http://en.wikipedia.org/wiki/Irish_cuisine