The language used to describe the foods we eat can have a huge effect on how we perceive them: “organic”, “artisan”, “homemade” and “handpicked” foods sound slightly more tempting than the prosaic “tinned”, “rehydrated” or “freeze-dried”. Another adjective that can whet our appetites is “natural”, while we tend to associate “processed” food with long lists of ingredients we can’t pronounce. But...