This term has been around since 1610. It originally meant a well-fed servant. The more famous use in reference to the Yeoman of the Guard of the English royal household and later to the Warders of the Tower of London dates to 1671. Beefeater is quite literal in origin, being a reference to the diets of well-off and spoiled servants. It contrasts with loaf-eater, a reference to a servant who eats the bread provided by his master, a term that dates back to Old English, hláfǽta.
It is often incorrectly postulated the term comes from a supposed French word, buffetier. This alleged root, which would mean one who eats from a buffet, does not exist. Sometimes the word beaufet is presented as a transitional form, but this is simply a 17th century alternative spelling of buffet and appears later than beefeater.
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2013, by David Wilton