A recent headline declared "bye bye booty, heroin chic is back," referring to a fashion look in the 1990s and 2000s that glorified women with ultra-thin figures. But the backlash to the headlines from people recalling how this trend harmed their relationships with food and their bodies, shows that plenty of people are not interested in going back. So what really makes a "trend" go in and out of fashion? 

Professor Sabrina Strings says that while we may have had a few years in which having curves was considered fashionable, the thin ideal has never truly gone "out" of style. It's older than America itself — but just like America, it’s rooted in racist hierarchies. 

Professor Strings is an associate professor of sociology at the University of California, Irvine and author of "Fearing the Black Body: The Racial Origins of Fat Phobia."