In south american countries, there's a concept called a "basic basket" ( https://es.wikipedia.org/wiki/Canasta_b%C3%A1sica_de_alimentos https://es.wikipedia.org

In south american countries, there's a concept called a "basic basket" ( https://es.wikipedia.org/wiki/Canasta_b%C3%A1sica_de_alimentos https://es.wikipedia.org/wiki/Canasta_b%C3%A1sica_de_aliment... ) ( https://pt.wikipedia.org/wiki/Cesta_b%C3%A1sica https://pt.wikipedia.org/wiki/Cesta_b%C3%A1sica ), which, while not standardized, can at least give you a ballpark cost of the basic food needs of an average household for a month. One could conceivably figure out a reasonably not-out-of-thin-air number for each country by cross referencing the items in an arbitrary basic basket package and supermarket food prices in each country.