Gist of my comment was that although obesity is correlated with type 2 diabetes and with heart disease (note: not "obesity causes type 2 diabetes and heart disease"), it would be foolish to try and combat these "negative externalities" through excise on foods believed to contribute to obesity, for reasons basically the same as those the previous Labour govt gave for not cutting GST on foods believed to be "healthy:" complexity of administration and the likelihood of bizarre unintended consequences.
It's not clear to me in any case why exactly we might impose excise on one high-calorie food item which consists largely of highly processed carbohydrates with a high glycaemic index rating and significant fat content (eg, a chocolate bar), but not some other high-calorie food item featuring a similar level of highly processed carbohydrates with a high glycaemic index rating and a significant fat content (eg, a filled roll). The whole thing seems to come down to nothing more than assigning moral values to food.
For this I was declared "ignorant" by a fellow commenter, who went on to say:
One of the big problems in New Zealand is that people do not realise they are overweight because everyone else around them also has a weight problem. So it is hard to inform the public because they don’t even think there is a problem to fix.
This is certainly plausible - I recall my wife (at 175cm and 72kg) saying on a visit to Singapore that the women there made her feel like a sweaty hippo, and there's no denying that NZers are a bunch of lard-arses for the most part. As an argument though, it's seriously begging the question - that is, it's working on the basis that stating the problem is an argument for your solution: "People in NZ are fat, they don't even notice they're fat because everyone else is fat too, so it's important that we all adopt my proposed solution."
Er, well, no, not really. It may be evidence that we should adopt a solution, but that doesn't necessarily mean it has to be yours. The S59 debate was characterised by similar logical failure, in that a lot of people seemed to imagine the fact NZ has a child abuse problem was an argument for repealing S59.
When we consider taxpayer-funded lobby groups like the Obesity Action gubbins or proposals to ban advertising of certain foods or even to impose excise duty on them, it's worth considering the following: look at photos of your grandparents when they were young, or just photos in general from 50+ years ago. In my case, I have plenty of photos of relatives hanging out in the 1940s and 1950s, and there isn't a fat-arse to be seen - and this in Lancashire, with a diet consisting to a great extent of lard, dripping and beef suet. Compare that with a look round your own workplace lunch-room, in which tubby middle-aged women starve themselves on their nutritionist-recommended low-fat diets and wonder how they can possibly have gotten 30 kilos overweight. I smell bullshit - now, if only we could tax that...