This word first appeared in The Hobbit. In The Etymologies of the 1930s Tolkien had N. cram describe as “cake of compressed flour or meal (often containing honey and milk) used on long journey” and derived from ᴹ√KRAB “press” (Ety/KRAB). In drafts of The Lord of the Rings from the 1940s, however, Tolkien said this was not an Elvish word:

Cram was, as you may remember, a word in the language of the men of Dale and the Long-lake - to describe a special food they made for long journeys (RS/177).

This attribution of cram to the men of Dale survived into the publish version of The Lord of the Rings (LotR/369).