At least initially, it doesn't seem to make sense that sugary junk-food cereals are back in style. In many other aspects of American eating, we've been moving away from artifice and vice. Fast-food companies tout freshness. Salad chains are hot. "Plant-based eating" is the buzz-phrase for the year. Trendy paleo and keto diets made eschewing sugar cool. Companies have worked to eliminate artificial colors, flavors and preservatives.