Apparently “Get up in the morning, baked beans for breakfast” is an alternate lyric for the line “Get up in the morning, slaving for bread sir” in The Israelites by Desmond Dekker, a reggae song. Either that or it’s a commonly misheard version of that lyric. To confuse matters further, it’s sometimes misheard as “Bake beans for breakfast”. For what it’s worth, the two versions I just downloaded have the “slaving for bread sir” line.
Anyway, I hadn’t heard of the song until today. So the allusion (whether it’s to real words on tape or to something that just exists in a few people’s heads) was accidental.