They tried this stupid crap at the cafeteria where I work a couple of years ago. The idea was a total FLOP. Even after it was shown to be a losing idea, they ideologically held onto it as long as they could. After a few months of their cafeteria sales on Mondays dropping to near nothing, they eventually dropped it. (yet another instance of liberalism being all well and good until the tolerance of losing money is reached)
I'll bet it worked wonders for productivity as well as employees went out for lunch on Mondays - the whole reason for an employer to provide a cafeteria for employees anyway.