It's telling that, whenever the government (rarely) enacts laws that tax or ban consumables with negative externalities, they actually target the right thing. After troves of empirical evidence, they heavily taxed smoking and banned trans fat (I'm aware of the government's misguided early endorsement of trans fat vs. saturated fat, but science has progressed a lot since then). Recently, local governments have tried to tax excess added sugar. That has been less successful, but it's guided by the right thinking. Excess sugar in our food supply is unequivocally, empirically bad. The government has less of a basis to tax it since it's not paying for all our healthcare, but that would change under M4A. Moreover, there would be more money behind nutritional/health research, because that research would have a more tangible payoff: an approximate dollar amount saved in public healthcare expenditures.