A recent study in The New Journal of Physics attempted to measure how the global market has changed established regional cuisines. They used a lot of math and complicated algorithms to measure the use over time of what they called "idiosyncratic" ingredients (ingredients unique to that region), in the cuisines of Brazil, France, and Great Britain. For Brazil, they studied three different editions of the cookbook Dona Benta spanning a period of more than 50 years, and they found that although the recipes changed and became more international, they still called for certain same ingredients such as chayote (a favorite squash Brazilians call 'chuchu') as frequently as they did in the 1940's. This seems to predict that Brazilians will always love chayote, and will incorporate it cleverly into new recipes as their cuisine evolves.
As explained in ScienceDaily, the study also showed that cuisines evolve similarly, and that our "global food culture has not shifted some die-hard culture-based eating habits." That's exciting news to me, because it means there's hope that the unique cuisines of countries such as Brazil and Peru will withstand global influences such as McDonalds. Although come to think of it, even McDonalds incorporates some of those same idiosyncratic ingredients into their local menus, such as the Maharaja Mac in India, a Big Mac made with lamb. The McDonalds we visited in Peru always had a ice cream sundae made with manjar blanco (dulce de leche).
I guess a hundred years from now, Peruvians will still be eating lucuma, though it may be as a pizza topping, and Southerners will still be eating grits, though they may be grits made with steamed chayote and drizzled with dulce de leche!