Megnut — now reborn as an erudite and gripping food blog — has a great Memorial Day post tracing the history of "war food" from the southland's okra-based coffee-substitute during the Civil Ware right up to the Gulf War's MREs:
During the Civil War Southern civilians suffered heavily from Northern blockades and as the war dragged on, food supplies became quite limited. Southern food substitutions
became common when staples were no longer available. For meat people ate "[d]omestic animals, crows, frogs, locusts, snails, snakes and worms." When coffee ran out, it was "brewed" from "[o]kra seeds that were browned, dried sweet potatoes or carrots, roasted acorns, wheat berries."