"food" for anything, 1670s, from Latin pabulum "fodder, food, nourishment," from PIE root *pa- "to protect, feed" (see food) + instrumentive suffix *-dhlom.
Pablum (1932), derived from this, is a trademark (Mead Johnson & Co.) for a soft, bland cereal used as a food for infants and weak and invalid people, hence figurative use (attested from 1970, first by U.S. Vice President Spiro Agnew) in reference to "mushy" political prose.