Comment by PermutationCity

Yes, plans have pretty wide latitude on what they cover. ACA limited quite a lot by not only in plan design, but also what therapeutics must be covered. And you are correct, obesity is not one of them.

Medicare Part D (outpatient drugs) has wide latitude on what medicines they cover - it's actually smart for patients to shop their Part D plans if they are taking an expensive, chronic medication.

The only classes of drugs that Part D plans must included are:

Part D sponsor formularies must include all or substantially all drugs in the immunosuppressant (for prophylaxis of organ transplant rejection), antidepressant, antipsychotic, anticonvulsant, antiretroviral, and antineoplastic classes. (Page 28)

https://www.cms.gov/medicare/prescription-drug-coverage/pres...