Why is the marriage of salt and sugar so tasty? It might be due to a layering effect — combining one flavor of delight with another yields a delight two times greater. According to Barb Stuckey, a professional food developer, tasting something salty produces a pleasurable experience because it is a necessary nutrient. We have a built-in craving for it because we have no sodium storage system in our bodies, unlike other minerals such as calcium which is stored in our bones. Tasting something sweet, she says, signals calories, or energy, that our bodies need for fuel. She uses the following analogy to explain why experiencing two positive biological responses makes it very pleasurable: “It’s akin to hearing beautiful music while sniffing rose petals: two positive sensory stimuli.” Salt, as well as being a taste itself, is also a taste enhancer, so adding a bit to a sweet treat makes the sweetness more intense.

Sources: io9.com; HowStuffWorks.com