The history of the Irish diet is also a story of ourselves. Looking at the foods we ate in the past opens a door into what was happening socially, culturally and economically on the dirt floors of rural cottages, the stone hearths of the great houses, and the streets of our cities. What we eat now, compared with years gone by, tells a tale of the island’s transformation – and the when, how and how often of our eating habits are just as revealing.

Chicken: 3m a week

“Mr Leopold Bloom ate with relish the inner organs of beasts and fowls. He liked thick giblet soup, nutty gizzards, a stuffed roast heart, liverslices fried with crustcrumbs, fried hencods’ roes. Most of all he liked grilled mutton kidneys which gave to his palate a fine tang of faintly scented urine,” James Joyce wrote in Ulysses, a story set in 1904

Our meat-eating habits have changed considerably. This week alone three million chickens will be killed to sate Irish appetites. Fifty years ago people in this country barely ate chicken. In 1960 the World Health Organisation surveyed Irish consumption of all poultry – duck, turkey and chicken – and found that we ate 6kg each a year. By 1980 that annual figure had reached more than 20kg each. Today it stands at 22kg.

Traditionally, chickens and poultry were managed by women in rural settings and seldom killed for the home table. Eggs were a source of income rather than chickens being a source of protein. The eggs were sold to buy household goods or shoes for children – so a regular small income from farm poultry was crucial for women running households.

Eating a chicken was something of a rarity, but then so was eating meat in general. In 1936 the Irish diet consisted of only 7per cent meat, according to the National Nutrition Surveillance Centre. About a third was dairy and a quarter potatoes, the rest being cereals and seasonal vegetables.

Rise and fall of the potato

“Many Irishmen have but one day on which they eat flesh, namely on Christmas Day. Every other day they feed on potatoes and nothing but potatoes,” Johann Georg Kohl observed on his travels around Ireland in 1841

Ireland was the first European country to adopt the potato as a key crop when it arrived in Europe in the 1600s, and the turbulent period of the Cromwellian wars saw it spread rapidly through the country. Fields of wheat or oats could be burnt; potatoes were still good to eat after months in straw underground. The success of the potato also led to the decline of many pulses and cereals that had been part of the national diet in the medieval period. Beans, peas, wheat, oats and rye – even lentils – had been commonplace. Our overdependence on the potato brought death and social destruction to Ireland in the 1840s,when a blight from Belgium swept through Europe and then Ireland.

Yet the potato, along with dairy produce, remained the central food in Ireland for another 100 years. The first Irish national nutrition survey, of 1946-48, found a whopping intake of 549g each a day. But by 1990 our potato consumption had halved, beginning a decline that has lasted subsequent decades. Ninety-nine per cent of us still eat boiled, mashed or roast potatoes daily. But our preference for processed potatoes – chips, wedges and so on – rose from 13 per cent in 1980 to 26 per cent in 1990 and has now reached a point where they account for half of all the potato we eat, according to Euromonitor.

Pork, from chops to processed

“There was such an abundance of ackornes this yeare that it fattened the pigges” – runts – “of pigges,” the Annals of Clonmacnoise recorded in 1038

Pork is the most popular meat in Ireland; we each consume a huge 35kg a year. Chops and roasts are popular buys, but the most commonly eaten forms, particularly among children and younger consumers, are processed: bacon, sausages, ham, salamis and puddings. So in some respects pork is our most popular meat because of our love affair with salt. The pig has an important place in Irish food history, giving “torc” (boar) or “muc” (pig) to many placenames. Many rural and urban households kept a pig fattened on potatoes and scraps. Curing pork with salt made it last longer. From the mid-18th century, production of cured bacon moved into factories, and by 1862 we had perfected a method of injecting brine into pork, both as a preservative and for the taste. Processed pork accounts for more than half of the pork we eat, according to Safefood, and has become a focus of health messages linking bowel cancers to processed meats. Happily, though, the salt content of bacon is about half what it was 30 years ago.

Europe’s most avid beef eaters

“Steak. Steak was the thing,” said Myrtle Allen of Irish restaurants in the 1950s

Cattle have been esteemed in Ireland since the earliest of times, and beef was considered a food of high social rank even before we began exporting it to England in the 1600s. “The value of beef is about what people invest in it – their idea of it,” the food historian Regina Sexton says. “Beef has status in our customs and eating habits because cattle are the largest of the farm animals. Rearing a cow is so resource- intensive, therefore its meat demands a high price.” So prime cuts of beef were rare in most houses, and when beef did appear it was in the form of cheek, tongue, shin or offal. By 1993 total meat consumption in Ireland had increased by 74 per cent. Now we each eat about 16kg a year. We are still the largest consumers of beef in the EU, as other nations move to different proteins.

Dairy and cheese: an old tradition

“Cattle have no grass and hay does not give them milk . . . Consequently, only a pint of sour milk to be got for a penny now,” went an entry in the 1827-35 diary of Humphrey O’Sullivan, the Kilkenny author and teacher

Cheese for most people in late-20th-century Ireland meant picking slivers of foil off a block of Calvita, Mitchelstown Co-op’s hugely successful product. It’s only in the past 40 years or so that artisan cheeses have been produced, let alone sold in supermarkets. Dairy and cheese are key to the Irish food story. We know from molecular analyses of organic residues on nearly 500 Neolithic pots by Bristol University that dairying was taking place in Ireland between 4000 and 2500 BC and that foods made from milk – butter, cheese, curds, whey and everything in between – were popular.

Political upheaval and changes in landholdings and agriculture in the 17th century saw the traditions of milk and cheesemaking decline. They returned in the 19th century in the Anglo-Irish big houses, but rarely in domestic settings. Feeding Britain with butter effectively removed cheese from the Irish diet in the 1800 and 1900s. After the second World War creameries made commercial Ccheddar. Nowadays we each eat 5kg a year, according to Bord Bia, and have a cheese culture which stands toe to toe with that of France.

Fish: the church rose, fish fell

“Their seas round about supply them with all manner of shellfish, and other sorts, the choicest which ever came to Neptune’s table,” wrote a traveller in Ireland in 1670

Fish has a poor presence in the current Irish diet, but it wasn’t always so. Sir William Perry, writing in 1672, noted that fish such as salmon, pike, perch, eels and roach were caught in rivers and cooked over open fires. Earlier still, cod, hake, whiting, mackerel, skate and shellfish were popular in Viking Dublin. On western coasts, shellfish was not only part of the diet but also provided a thriving industry in extracting purple dye for the clothing of the nobility. Ironically, given Ireland’s Friday fish tradition, some link the recent decline in the consumption of fish to the rise of the Catholic Church, which advised that fish be a food of fasting and that red meat, in general, be avoided. In 1962 the average Irish consumer ate just 5.3kg of fish a year. Then Pope Paul VI gave bishops discretion in applying the ban on meat. By 1976 we were each picking the bones out of 12.4kg of fish a year. Now most fish is bought by older consumers, so the Catholic tradition may still account for a lot of sales of fresh fish. A lack of knowledge among younger consumers about how to prepare fish may account for the drop in consumption to 9kg each a year by 2000. It currently stands at 11.3kg per person.

Mealtimes: the rise of snacking

The three-meals-a-day model is changing rapidly, with more eating taking place outside mealtimes. Snacking and “dashboard dining” have become core eating occasions. Irish consumers snack on average 2.55 times per day, according to Bord Bia; it’s a model of eating that would have been alien 50 years ago. Now it is routine, supported by an abundance of 24-hour fast-food outlets, coffee shops and snack chains.

The profusion of snacking opportunities and the falling price of food has also increased portion size. We are eating not just more but also more often. “Portion sizes have become bigger, but they also vary because our meal patterns are changing. Because food is to hand it becomes a constant throughout the day,” says Regina Sexton.

Shopping: 2 hours a week in supermarkets

Huge changes in bread, cereals and vegetables have also occurred in the Irish diet, but the key transformation is simply the variety of foods available. Despite chefs and the media talking about local food and independent shops, most Irish people get their food from the supermarket, spending 2¼ hours there in an average week.

As the food writer Michael Pollan says, the western diet has changed more in the past 40 years than it did in the the previous 10,000. Supermarkets have been the main agent of that, and Irish diets, like all aspects of our lives, have become more international, and processed foods suit our time-poor lives. While there is much trumpeting of “heritage” foods, and traditional Irish ingredients, we tend not to buy them. Most shoppers look for low prices and convenience, and the price of food continues to fall.