The state of Ohio does not tax food but there in one exception food eaten on the premises of a restaurant is taxed food to go is not taxed What is a reasonable economic explanation for this?

You have to understand that taxes are not the rule, but the exception. They are not universal and then repealed, but created out of need. Likely, in a bygone era when people really cared about what the government did, the poor people would have protested to no end a tax on foodstuffs. When a loaf of bread is a nickle, you really don't want even a cent's tax. The wealthy, however, wouldn't mind too much a tax on dining out, which of course, would have been a luxury then. It is typically the pattern anywhere to tax the wealthy most.