There's more that makes us scarf entire bags of salty snacks than just lack of self control.
Salt is necessary for the human body, and our brains are hardwired to crave it.
But dump a whole salt shaker onto your pork chop, and your dinner is ruined — so there's something else going on in our brains that keeps us from overdoing it with the vital mineral.
Our bodies use salt (sodium chloride) to regulate fluids and to create nerve impulses. Yet unlike other vital minerals, such as calcium (which we store in our bones), we can't hide away salt for later use. Salt on its own is also a rare find for many terrestrial animals.
So when we do find salt, it's in our best interest to eat it — hence our near-incessant cravings for the stuff.
The taste alone, however, doesn't fully explain our obsession with salt. Sodium chloride also acts as a flavor enhancer "to improve the perception of product thickness, enhance sweetness, mask metallic or chemical off-notes, and round out overall flavor while improving flavor intensity," according to the National Academy of Sciences.
But too much salt is definitely not good for us, either. Drinking sea water will kill you, and a diet with consistently too much salt has been linked to heart attacks, stroke, and high blood pressure. Overindulging on salt also puts heavy a burden on your kidneys and can lead to painful kidney stones.
Thankfully, our bodies have a mechanism to prevent us from salting ourselves to death.
Two of the five fundamental flavors of human taste — sweet and umami (a taste for protein) — are appetitive, meaning they can increase our appetites for calorie-rich foods, like sugary fruit and savory meat. Two others — bitter and sour — are generally aversive and keep us from eating poisonous plants and animals.
Salt is special in that it can trigger both appetitive and aversive behavioral responses, depending on how much you eat.
A study in the journal Nature, for example, found that high doses of salt hijack our bitter and sour taste receptors, making overly salted food unpalatable. The researchers also found that mice without this taste pathway had no aversion to high levels of salt.
Like many other of our other tastes, our love of salt helps us overcome its natural scarcity on land. But unlike our modern tendency to gluttony with sweet and fatty foods, our love of salt is also offset by our strong dislike of over-salted food.
So next time you're elbow deep in a party size bag of Doritos, remember: You're just answering nature's call for a mineral that is vital for your wellbeing. But you may want to put the bag down sooner rather than later to help ward off the hypertension and kidney stones.
