Taken from some of the excellent photo galleries on the Time website.
I have included countries I have been to, but I can't say I ate like a local all the time. I normally eat a simple breakfast (muesli, bread, coffee) but in places like Japan breakfast was often just a smaller dinner with rice, seawood and some veg. I couldn't even stand the smell of such food in the morning but I'm sure they would react with equal disdain to an Irish breakfast.
Guatemala: The Mendozas of Todos Santos
Food expenditure for one week: 573 Quetzales or $75.70
Family Recipe: Turkey Stew and Susana Perez Matias's Sheep Soup
United States: The Fernandezes of Texas
Food expenditure for one week: $242.48
Favorite Foods: Shrimp with Alfredo sauce, chicken mole, barbecue ribs, pizza
France: The Le Moines of Montreuil
Food expenditure for one week: 315.17 euros or $419.95
Favorite Foods: Delphine Le Moine's Apricot Tarts, pasta carbonara, Thai food
Great Britain: The Bainton family of Cllingbourne Ducis
Food expenditure for one week: 155.54 British Pounds or $253.15
Favorite foods: avocado, mayonnaise sandwich, prawn cocktail, chocolate fudge cake with cream
Japan: The Ukita family of Kodaira City
Food expenditure for one week: 37,699 Yen or $317.25
Favorite foods: sashimi, fruit, cake, potato chips
Mexico: The Casales family of Cuernavaca
Food expenditure for one week: 1,862.78 Mexican Pesos or $189.09
Favorite foods: pizza, crab, pasta, chicken
China: The Dong family of Beijing
Food expenditure for one week: 1,233.76 Yuan or $155.06
Favorite foods: fried shredded pork with sweet and sour sauce
Can't find relevant figures for Ireland, but I reckon for 2 kids, 2 adults it would be around €200, which at the moment is trading at $275.
Have never made it to the continent of Africa, but just thought I'd include Chad to show the other end of the spectrum.
Chad: The Aboubakar family of Breidjing Camp
Food expenditure for one week: 685 CFA Francs or $1.23
Favorite foods: soup with fresh sheep meat