I was on that program. And I ate the liver. I steamed it in a bit of onion broth. I made my tuna salad with chopped canned green chile which meant no mayo required. It is, BTW, delicious. The white bread was plain old one-ounce slices of Wonder Bread.

Barnes & Noble has a 1920s Girl Scout Manual which suggests that eating bread full of bran is not a good idea because it's so much harder to digest. I do have a vague memory of that being a concern even into my youth in the 1950s.