Why do sweet and salty taste so good together?

Salted caramels. Chocolate-covered bacon. Ice cream and pretzels. Kettle corn. And the classic kid combo -- French fries dipped in a milkshake. Is your mouth watering yet?

The marriage of salty and sweet is one that shouldn't work, but magically and deliciously does. We can't get enough of it. Too much sugar is overly intense and too much salt simply tastes terrible, but when you mix the two, the combination is heavenly. What's the science behind this phenomenon?

First, let's talk about taste. We have five primary tastes -- sweet, salty, sour, bitter, and umami. Umami is a relatively newly discovered taste, and is Japanese for savory or delicious. Contrary to what you probably learned in elementary school, each taste bud can sense all of these. Our bodies evolved with taste buds for a reason. For example, we taste sweet in order to fuel our bodies with carbohydrates. We taste sour or bitter to protect our bodies from something potentially damaging. We taste salt to provide our bodies with a necessary nutrient.

Salt isn't just a nutrient, either. It's a flavor enhancer. So, it stands to reason that if you mix sugar and salt, the salt enhances the sugar flavor. Chefs call this flavor layering, and the right mix -- not too sweet and not too salty -- gives your brain a positive biological response.

Another reason we love sweet and salty is a brain experience called sensory specific satiety. Because humans are omnivores, we're wired to desire a variety of foods and tastes. Eventually we'll tire of the same taste over and over again. If you constantly gorge yourself with sweets and only sweets, at some point you'll lose your taste for them. The same goes for salty. However, with flavor layering, flavors meld together in your mouth without giving you a specific taste. By avoiding sensory specific satiety, salty/sweet tastes even better and keeps you coming back for more.

And finally, because we crave sugar for the carbohydrates to keep our bodies going, and we crave salt for the essential nutrition, sweet and salty really is a perfect match.