Taxes on food are good for the poor.

When taxes were taken off of food, they were spread upon everything else that poor people buy.

"Poor" people do not pay food taxes. They are using food stamps and other government assistance not subject to sales tax in the first place.

By supposedly relieving them of a tax they were not in fact paying, an additional tax was levied on everything else they buy.

The net effect of not taxing food is the most regressive tax imaginable.

Update; I have come across an opposing point of view on the Journal's Op-ed page, link.