Some say food is the gateway to culture, and culinary tourism is booming—with people estimated to spend over $1 trillion this year alone. But not every traveler wants to dive headfirst into unfamiliar dishes. Should we judge? Science seems to offer a pretty solid explanation for the behavior. / The secret to lasting love might just be knowing how to fight (16:32). On the show: Niu Honglin, Steve Hatherly & Yushan