My brother just wrote down these lyrics for me as I am gathering old songs, etc. that we remember our parents singing. The tune seems to be similar to "My Bonnie lies over the Ocean", if you are familiar with that old tune. I'm sure the lyrics have gone through my changes as it was remembered by different people over the years.

On Monday we have Bread and Gravy
On Tuesday it's Gravy and Bread.
Wednesday and Thursday it's Gravy on Toast
But that is just Gravy and Bread.
Friday, it's whole wheat and gravy,
Saturday, it's rye bread instead.
But Sunday's a treat, though we never get meat.
We get gravy without any bread,
Oh Yeah, gravy without any bread.

Best Wishes