Humans have been processing foods for millenia. So why is “processed” now synonymous with “unhealthy”?

When you hear the term “processed food” these days, chances are you’re thinking of something high in calories and low in nutrients. There’s a reason for this association: Some of the most popular and recognizable processed foods include sodas, potato chips, and even cereals—all of which have been maligned for their high sugar or salt content. But that hasn’t always been the case. Did you know that before the advent of soda, seltzer water was prized for anti-microbial properties? It was actually first developed specifically to address sailors’ distaste for stale water on ocean voyages. Only later did the water—“impregnated with fixed air,” as its maker described it—become a base ingredient for sugary drinks. BBC details the unexpected history of some of today’s most common processed foods—and how technology contributed to their current association with unhealthfulness—here.