There was a brand of bread in the 70's that had "sawdust" in it:
In 1977, "low-calorie, high-fiber" Fresh Horizons brought comedy to the bread aisle. That's when consumers learned--from newspaper articles, not ads or labels--that the bread's fiber--listed as "cellulose" on the label--came from wood pulp.
I ate that bread, and it wasn't bad.
That stuff is surprisingly accurate; shopping by picture phone has been met and exceeded, solar energy is growing big and with many applications, and I'm sure there are much more surprising things than sawdust in synthetic food.