Amy Halloran interviewed Jonathan Stevens and Cheryl Maffei of Hungry Ghost Bread fame (in Northampton, Massachusetts) and at one point Stevens says:
Going out to dinner with my dad, when bread would come to the table he would grab a piece, and if you could take the center out and make it look like dough again, we couldn’t eat it. It was deemed fundamentally undigestible, and this is before any of us knew anything about sourdough.
This is what is supposed to happen when you squeeze the crumb of some real bread:
And here’s what happens when you try the same thing with an entire loaf of real bread:
Crappy cheap bread will not spring back like that.