High sodium levels in food have been linked to stimulating our brains pleasure center, shown to lead to heavy salty snack addiction.
According to recent study salty snacks or high sodium meals are shown to release our pleasure cells (Opioids), which in order branches into an increase in sodium with in our diets. Salt is on the increase to keep us happy!
This would be why the bad foods are so addictive, most contain higher than average levels of sodium. Our average daily allowance should not be more than 1/4 of a teaspoon of sodium.