salt-free diet vs low-salt diet

salt-free diet and low-salt diet both are nouns.

Word	Noun	Adjective	Verb	Adverb
salt-free diet	Yes	No	No	No
low-salt diet	Yes	No	No	No

As nouns, salt-free diet and low-salt diet are synonyms defined as:

salt-free diet and low-salt diet: a diet that limits the intake of salt (sodium chloride); often used in treating hypertension or edema or certain other disorders

Other synonyms of salt-free diet include low-sodium diet.

salt-free diet (noun)	low-salt diet (noun)
a diet that limits the intake of salt (sodium chloride); often used in treating hypertension or edema or certain other disorders	a diet that limits the intake of salt (sodium chloride); often used in treating hypertension or edema or certain other disorders