Originally Posted by YVR Cockroach

The nutritional information labels are there for a reason. Read them.

Some minimally-processed foods, such as canned tomatoes, can have widely varying sodium levels from negligible to very high.,

Beware of "reduced/low sodium" or even "no salt added" labels: Some food stuff are naturally high in sodium, and the normal sodium levels in the non-sodium reduced versions can be absurdly high in the first place (so merely not-so-absurdly high).