Salt or sodium causes water retention

[Karen1]

Salt or sodium causes water retention and can also slow down your metabolism. Salt substitutes are still a salt and will cause the same problems that sodium does. It is better to avoid added salt or salt substitutes while on the losing weight.

[Maryann]

Most of the foods I like seem to have either too much saturated fat or too much added salt (sodium).
1. Should I choose the lower fat, lower sodium, or neither?
2. How do I find out if sodium will raise my blood pressure?
Thanks.