I teach a class called ‘Decolonize Your Diet,’ and I talk about the Spaniards arriving in Mesoamerica. One of the first things they tried to change—in addition to religion— was the way people ate. They introduced wheat and tried to make eating bread something that was seen as more valuable than eating corn. They outlawed amaranth, and in South America they outlawed quinoa.

I tell my students to think about how the dominant powers are invested in controlling what their subjects eat, and then...