I live in San Diego, where I teach courses on urban and food geographies and conduct research on the relationship between food and ethnicity in urban contexts. In recent years, I started to notice a pattern playing out in the city’s low-income neighborhoods that have traditionally lacked food options. More ethnic restaurants, street vendors, community gardens and farmers markets were cropping up. These, in turn, spurred growing numbers of white, affluent and college-educated people to venture into areas they had long avoided. This observation inspired me to write a book, titled The $16 Taco, about how food — including what’s seen as “ethnic,” “authentic” or “alternative” — often serves as a spearhead for gentrification.