The opposite of a health benefit is a health penalty. Googling "health penalty" "health benefit" comes up with quite a few significant links.

This pair of opposites is probably applicable in other contexts as well (surely in economy and finances).

The opposite of a health benefit is a health penalty. Googling "health penalty" "health benefit" comes up with quite a few significant links.

The word pair fits also etymologically quite nicely. Penalty as well as benefit are originally human acts: A punishment (Latin poena), and a good deed (bene factum). Both terms imply some sort of book keeping, as in in accounting or a game. Both terms for originally human acts have acquired an impersonal meaning as well: "The tax benefits of marriage", or "The Financial Penalty for LGBT Women". Using the term penalty, even when describing a consequence which is not the act of a single person, evokes an image of a rule based framework, like a sports game or a court case. Certainly some possibly imaginary score is lowered.

Both terms are frequently used in economics where they apply quite naturally, because it's a rule based framework where scores are kept.

Using them in medicine applies this concept of rule-based score keeping to a person's health and interactions, thus "economifying" or "gamifying" it.

The general term for that, not only with health, is penalty. Googling "health penalty" "health benefit" comes up with quite a few significant links.

The opposite of a health benefit is a health penalty. Googling "health penalty" "health benefit" comes up with quite a few significant links.

This pair of opposites is probably applicable in other contexts as well (surely in economy and finances).