Funnily enough, the cost of our medical care is also heavily externalized. Pharma companies dump all of their toxic medical waste into lakes, streams, rivers, forests, and the ocean. Allopathic drugs are tested on animals all the time. Medical waste is a huge problem worldwide. We are literally living in a system of externalities.

You would neither be able to afford the food you eat nor the medicine you'd need to cure ailments that arise from that unhealthy food if those industries weren't subsidized by the government and the costs weren't so heavily externalized.