Synonyms for Unhealthful (same or very similar meaning)
WordNet sense 1 (detrimental to health):
insalubriousWordNet sense 2 (detrimental to physical or moral well-being):
unwholesomeWordNet sense 3 (not sanitary or healthful):
insanitary, unsanitaryWordNet sense 4 (not conducive to good health):
unhealthyFrom the ODE community, based on WordNetadd/edit