healthy is more of a modifier that narrows down the categorization of what we're discussing, less often used as a highlight of an intrinsic property. also there's the fact that medications are often saddled with less than ideal side-effects and are resorted to only as a trade-off where the issues caused are less deleterious to a patient than the issues they address, so not even they are intrinsically healthy. The reason healthy food is a concept is because the majority of people have a tendency to enjoy food that is unhealthy.