Obesity and Medicare

It was recently announced that obesity treatments will now be eligible for Medicare coverage. I remember reading a number of objections to this decision, both in the blogosphere and elsewhere, though I can't find them now. One of the most plausible objections, phrased in the form of a defensible argument, goes something like this.

1. Obese people are obese (at least in part) by virtue of their own free will.
2. If these people became obese of their own free will, it is likely that anti-obesity treatments will be less effective, since the patients are not behaving in a way that would reduce their obesity.
3. Less effective treatments should not be covered by Medicare.

This is, I think, a utilitarian argument (though very rough and underdeveloped). There is a certain, limited amount of money available for health-care expenditures, so using some of it on less effective treatments is inadvisable.

Another argument goes like this:

1. Obese people are obese (at least in part) by virtue of their own free will.
2. This means that their obesity is (at least in part) their own fault.
3. Medical care should not be provided to those who harm themselves.

I can't see any way to defend this second argument, though it is also underdeveloped. In fact (and this shouldn't come as any surprise), I think physicians have a positive moral duty to heal and not to try and establish the fault (or lack thereof) of their patients.

Both arguments, though, have to come to terms with the following objection. How does one differentiate between personal decision and outside factors in the etiology of disease? It would be even more complicated to apply such differentiation (were it possible) to rationing of medical care.

To put it in more concrete terms: which of the following diseases make a patient more or less "blameworthy"? Cirrhosis of the liver; AIDS; obesity; lung cancer; heart disease; trauma sustained in an automobile accident (with a seat belt? without a seat belt?); etc., etc., etc. Keep in mind that these are some of the most common causes of morbidity and mortality in the U.S.
(Another way of going about it is to ask the question: are there other government programs which encourage patients to stop unhealthy behavior? At what point would a patient become ineligible for help in quitting smoking?)

This train of thought is inspired by a post over at Close Range. I'm not a philosopher (although I do read and enjoy philosophy), and these thoughts lack rigor. But maybe Marc can give me some advice.