Leftovers, anyone?

If someone looks very ill, as in almost dead, you might call them "death warmed over." Apparently, the British call it "death warmed up."

A clever play on this phrase comes in the title of a book on funeral practices, entitled "Death Warmed Over: Funeral Food, Rituals, and Customs from Around the World" by Lisa Rogak.

I didn't find much in way of the origins of this phrase. Suppose it's one of those common sense things. But why would you warm death up, like leftovers?

Which reminds me of "momento mori," the Latin phrase meaning remember death. For it is only in facing our own mortality that we learn to appreciate life. Brief as it is.