According to archaeologists and anthropologists good teeth in long dead guys can be a sign of not a lot of carbs in the diet. Bread and circuses notwithstanding.
The Egyptians used grinding stones that left bits of abrasive dust in their bread, which at times led to tooth wear and (possibly, in the case of the Pharaoh Hatshepsut) death due to dental abcess.
The bread dole was a continual thing in Rome for hundreds of years. For maximum political impact, it was combined with The Games, so folks had to get the Circuses in order to get the Bread, which means carbs. That’ll teach ‘em.