A big part of efficient health care is to keep people out of hospitals. Prevent, inform and make basic health care easy, accessible and inexpensive. If this patient you're talking about had the option of going to a local doctor for a basic diagnosis and medicine for free (or a couple of dollars), I guess he would have done it. If his only option was going to a hospital where the doctor would give him unnecessary treatments and squeeze every dollar out of him while losing his insurane for the rest of his life, a first sign of a disease would mean as much as a personal bankruptcy for him. It's no wonder people are going to try to live with easy-to-cure diseases until it's too late and expensive treatment is necessary. You say he's an idiot, but actually he just decided that getting rid of a small inconvenience wasn't worth a personal bankruptcy.
Besides, the whole financial incentives system is broken. If a 400lb patient comes to the cardiologist, what is the financial incentive to just assign the patient a lifestyle coach, which is the only long term cure for his/her problems?