I'm with rebelmum1 on this one. Of course, people should be free to do what they wish - smoke as much they want, drink as much they want, eat as much as they want. Or to paraphrase JS Mills, everyone has the right to act as he wants, so long as these actions do not harm others. On that basis, I really don't care how fat or thin people are in principle.
Unfortunately, however, we live in world of limited supply of goods and services and therefore certain actions do harm other people to some extent. Everything involves choices. We can't fund everything we need. If we spend more on the NHS, we have to reduce spending on say, education. If we spend more on defence, we have to reduce spending on say, social security. Society has to make prioritise.
On the same basis, conceptually, the 60 a day smoker who needs a lung transplant is denying a new born baby an incubator in the local hospital; the guy who's drunk 9 pints a day since he was 18 and has chronic liver disease is preventing an increase in pension payments; the guy who needs a heart bypass because he's chronically obese reduces funding for books in schools.
More practically, individual health trusts have to allocate their budgets around their needs - if they have to treat more people suffering from illnesses caused by obesity then they have to reduce spending elsewhere. This seems pretty straightforward to me. Equally, it seems pretty straightforward to me that unless you suffer from an eating disorder or a physiological problem which unavoidably results in obesity, you are making a choice. It might not be a simple choice, (e.g. you might eat comfort food, you might not have the time to exercise as much as you like, you might find it hard to shift weight etc) but you're making a choice in the same way that a smoker buying a pack of fags is making a choice or someone getting a crate of beer in for the weekend is making a choice unless you're actually unable to exercise any free will or have any understanding of consequence of course(e.g. an addict or a child) but that's fairly rare.
I drink too much. Not loads too much, but more than I should. I used to smoke loads too. Largely stopped now apart from the occasional sneaky one. If I turned up at the doctors with a disease related to drinking/ smoking too much and he said, "sorry, you've brought this on yourself, we'll do our best to treat you, but you're at the back of queue" I wouldn't be happy obviously but I think it'd be fair enough. I like drinking. I luuurved smoking. I know/ knew they've got health risks but I still do/ did it. I think that's entirely fair way to prioritise health spending. Why would this not apply in the case of obesity?