I love the whole "make smokers/obese people/whatever pay for treatment" angle, because it's just so, so ridiculous. It's so absurd it makes me laugh.
Fatty twats like me who smoke and drink die young, often before pensionable age - we don't consume much NHS resource, because by the time we're diagnosed then it's already metastatic and a month or so in a (low-cost) hospice is all that's required before we pop our clogs. Having, of course, spent those short years contributing tax far beyond what we use, including that on tobacco and alcohol (which I have no problem with - big up the welfare state
)
Those that eat well, don't have any unhealthy vices, exercise regularly etc - they live to a ripe old age, usually developing a host of comorbidities (heart failure, COPD, diabetes etc), and have numerous hospital admissions in their last decade of life. The financial burden on the NHS and SS is far greater for the healthy people than idiots like me who'll be unlikely to see 50.
I'm not for a second advocating an unhealthy lifestyle, but it's not the smokers, obese etc that are putting such a burden on healthcare. Quite the opposite.
There was a reputed peer-reviewed journal paper that studied this in depth a few years ago, but I'm buggered if I can remember which journal it was in.