We're told, endlessly, that smoking must be even more highly taxed because smokers cost the NHS oodles of money. Further, that salt, fats, junk food, should all be taxed because fatties cost the NHS lots of money.

This is nonsense, nonsense on stilts.

There are good reasons to suggest to people that perhaps they shouldn't smoke: it's not particularly good for them after all. But having suggested, having checked that they are aware of the trade off they are making, that's as far as we should perhaps go. Taxing smokes highly because demand is relatively insensitive to price is also fine: we do have to get tax revenues from somewhere. The case for doing something about obesity is of course much stronger. Over and above the danger of ill heath to the porkers themselves there is of course the societal pollution of us all being confronted with the snorting beasts in the streets. Quite enough justification for us to tax them (by the way, the definition of obesity is 20 lbs heavier than the person complaining about obesity).

But to argue that either hamburgers or tabs lead to costs to the NHS is simply wrong:

The researchers found that from age 20 to 56, obese people racked up the most expensive health costs. But because both the smokers and the obese people died sooner than the healthy group, it cost less to treat them in the long run.

On average, healthy people lived 84 years. Smokers lived about 77 years and obese people lived about 80 years. Smokers and obese people tended to have more heart disease than the healthy people.

Cancer incidence, except for lung cancer, was the same in all three groups. Obese people had the most diabetes, and healthy people had the most strokes. Ultimately, the thin and healthy group cost the most, about $417,000, from age 20 on.

The cost of care for obese people was $371,000, and for smokers, about $326,000.

And as Kip Viscusi has pointed out, when you add in the costs of the state pensions that those who die young don't get, smoking and gorging save the government vast sums of money.

There are perfectly good arguments to use in persuading people to not smoke or to eat well. "Wouldn't you like to live longer?" is a useful one for example. But if the answer that comes back is "No, I'd prefer to have a cigar right after this triple scoop sundae" then that's just up to the individual and how they wish to chart their course through this vale of tears we call life.

Lying to everyone about the costs of health care just doesn't help at all. So could various people please stop doing it? Thank you, much obliged.