The sceptic in me thinks these things are all a ploy to get us spreading hate.
Look at the smoker threads on here, hurls of abuse for people who are doing nothing illegal and exercising their right to do something they enjoy.
I would bet my life that not everyone on those threads are slim of build and eating healthily.
So you have the smokers saying "well smoking suppresses my appetite so at least i'm not obese like all you fat people costing the NHS however many X million".
Then you have the argument that the obese are more likely to die suddenly say of a heart attack, which wont cause the NHS as much as a "generally healthy" person who has the misfortune of suffering cervical cancer or dementia in later life and the relatively expensive treatment and care that the NHS has to fund.
Its all 6 and 2 x 3s as far as I am concerned, and I don't think anyone of us is unaware of the risks of overeating, bad diets, smoking, or alcohol. But we still do it, and we are always going to do it because unless we are a smoker AND a drinker AND obese, we can all justify it by saying well i'm X but at least i'm not Y. And if we do happen to be all 3, we can then say well hey-ho, I'll probably die pretty young and save the state a fortune in pensions and winter fuel allowance and bus passes and old age care.
The whole thing is just bloody stupid imo. Lets say tomorrow everyone stopped drinking, quit smoking, and lost weight. We now have a whole generation of people paying considerably less tax, and statistically living longer. So maybe we've saved the NHS a few quid, but we've lost £13billion from smokers, £11billion from alcohol duty, however many million from multiple clubs, bars, breweries, and jobs created by these industries, AND we have a huge pensions bill to pass on to the next generation with a huge gaping whole in tax revenues.
Yeah, somehow I don't think the Gov and all the do-gooder busy bodies are going to be overly chuffed about that. 
Live and let live