nitpicker –
Once you grant the government the right to ban the foods you consider to be “non-foods”, what will stop them from doing the same to foods that you do consider to be edible.
The point is, that just as you make certain distinctions about what you believe you should and shouldn’t eat, each person should have the freedom to make similar of different choices. If you believe that margarine is not food, then by all means, don’t eat it. But why should I be bound by your opinion?