Studies have shown that the long term intake of salt will cause vasoconstriction (generalized narrowing of small arteries due to activation of vessel wall muscles) and thus might cause hypertension even in healthy subjects.
Salt should be added moderately to food. No salt added is even better.
Caution is of utmost importance for healthy subjects with a familial history of diabetes, since they are at risk of becoming diabetic at a certain age.
Sugar should be ingested in moderate amounts; physical exercises are the best way to burn the energy it produces, and lose fat tissue it causes.