When you’re looking at the nutrition label on packaged food, how much sodium is okay? It’s important to know, since up to 75% of the salt in our diets comes from packaged foods. So use this simple ratio to keep your sodium in check. It comes from Dr. David Katz, director of the Yale Prevention Research Center. He says look for a 1-to-1 ratio of calories to sodium, or less. So if a food has 150 calories per serving, it should have no more than 150 milligrams of sodium.