If nutrition facts regulations went away tomorrow, I suspect the market would enforce their existence anyway.

I think consumers want to know what is in the food they're eating, so you would get many startups who study what makes something healthy, or finding cheaper ways to list calories and ingredients, instead of listening to the government telling you about the food pyramid etc.

Even if customers deem it too expensive to pay for the nutrition facts, then how do you or others gain the right to intervene in a voluntary act between two people?