Well, churros probably are involved.
Until Europeans (the Spanish) arrived, the natives had no cooking oils, no sugar and very little animal protein, particularly in certain more barren parts of the inland Americas. Sheep, cattle, domesticated goats and draft or transportation animals such as horses were all brought by the Spanish.
Indians weren’t immediately able to adapt to this change in diet, although I suspect that it was really the change to a sedentary lifestyle in the 20th century that did them in.
BTW, have you ever had authentic churros? They are awesome and there is no comparison with fast food or frozen churros. When I was a boy, I used to go spear fishing at Punta Banda, and there was a push cart vendor there who fried them fresh in oil. Hot, crunchy, tender and sweet, like donuts from heaven.
True only of the over-populated farming areas, mainly Meso-America but also possibly including the Andean region.
North America, for instance, was lightly enough populated that there was plenty of access to animal protein from game.