Salt helps you retain water, it is necesary for keeping your body healthy and hydrated. On the other had too much salt, which is incredibly easy to consume can cause the exact opposite holding onto the water your body needs and causing high blood pressure. You need a maximum of around 3 grams of salt a day for a healthy person, that can easily be consumed in one modern day meal, not even a whole meal, just one plate, since sodium i a very common preservative.