Grape-nuts! No headache or “tummyache”! Fully cooked, pre-digested! Possibly regurgitated by a bird!    That is a LARGE warning box on the front of the package. And that’s not even counting “Don’t try to cook this food!”  The only warning needed on the grape-nuts box is that it’s made of condensed cardboard pellets.  University of Chicago Magazine. 1908.