WordNet (r) 3.0 (2006):

health food
    n 1: any natural or prepared food popularly believed to promote
         good health

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "health food":
   board, bread, bread and butter, caudle, cheer, comestibles,
   cottonseed flour, creature comfort, cuisine, daily bread, eatables,
   edibles, fare, fast food, feast, food, food and drink, foodstuff,
   fruits, ingesta, junk food, kitchen stuff, liver, meat, nuts,
   provender, provision, soybeans, spread, sustenance, table, tucker,
   viands, victuals, vittles, wheat germ, whole wheat flour, yogurt