Suzie, I agree, it's easy to assume that, if junk food costs more, through tax,that people would buy less. The demand is relatively inelastic for the group that such a tax would target. Plus the supermarkets are always going to have specials, so the tax, although still being collected, would be ineffective. There was a young mum interviewed in the local paper, recently, who had sincerely believed that she was being a 'good mum' by providing all of the food groups in the form of fast food. She had never been taught to boil peas or make mashed potato, let alone cook meat, eggs, etc.

I believe that there is a huge resurgence in home growing of vegetables, herbs and keeping chickens for eggs in Britain via the landshare (http://www.landshare.net/) organisation where people seeking an allotment style garden are connected with those with a spare bit of land, such as farmers, utilities and councils. The flow on effect is that there is a big interest in home cooking. There is, of course, a history of allotment style gardening in Britain, but no such history here.

In short, I'm not sure what the answer is for Australia.

Here's a bolshie notion ...

The reason that junk food is so cheap is that the wages and working conditions in the industry are well below the value that the consumer puts on their own time.

There I've said it.

The junk food industry is the most efficient bare bones operations we've got and it relies on kids and a marginalised workforce to do it. I suspect that quite a large slab of the processed food industry operates on low wages and poor conditions.

So perhaps one of the most effective things that those concerned with the whale-isation of the nation could do is start pressing for significant improvements in the wages of the fast food workers.

Wouldn't solve the problem entirely but would take a decent bite out of it and have in some ways the same effect as a tax.

In my sleepy little town we have no traffic lights and no fast food outlets aside from a hamburger joint or two... and one pedestrian crossing. Yet the average size of the locals is up there with a two door kelvinator.

The local supermarket sells an enormous array of frozen fast food equivalents - pre-made meals dripping with luscious transfats, salt and sugar. In fact it would not be possible to put together your simple brown rice and lentil curry - since neither are stocked. Pizzas again kids? We had pies last night.

I agree wholeheartedly that a fat tax is not enough, but I worry that such arguments are often construed to suggest that it would have no positive effect. I really don't think that's the case - a fat tax would very likely have a positive influence.

Most of the approaches we've seen are based around education and awareness and have some effect, but nowhere near enough. In my view, this is because the buyer gets the benefit (the food) straight away, and pays the cost of the choice (poor health) much later down the track. Inceasing the price makes the cost of a poor choice much more direct at the time of the decision, so should affect the decision more strongly.

Increased prices have helped to reduce use of cigarettes and alcohol, so why shouldn't they also work with food? It couldn't do much harm to try.

It won't be enough to do the whole job, but in combination with a range of other measures it should help.

Allowing the government to be involved in any way on this issue would appear to be a major mistake. They simply can't be trusted to give good advice when:

a) their dietary recommendations over the last 30 years have been completely unscientific (note that their advice coincided with the rise in obesity)

b) they are subject to lobbying and electoral consequences from various economic interests, most notably grain farmers and various food manufacturers

And unfortunately as this series on obesity has shown, those in the academic and medical professions charged with researching and addressing this problem appear to be just as clueless about the fundamental causes of this epidemic.

The readers have merely been subjected to the usual speculation, dogma and scientifically baseless explanations about the causes of the epidemic (gluttony, lack of exercise, lack of vegetables).

I agree with Suzie.

Also, we already have a 10% fat tax - the GST. It's applied to processed foods bought in shops and all restaurant and takeaway foods. Therefore fresh fruit and vegetables currently have a comparative price advantage.

The fact that this advantage has not had any discernible impact either on people's buying choices or waistlines (and as the GST has been in place for more than 10 years now, you would think that any impact would've shown up) implies that you would need a very large tax to change people's behaviour. This would also make it a very regressive tax, disproportionately affecting the affordability of food for lower income populations, and without clear evidence that the obese would become thinner as a result.

Obesity is not like smoking-induced lung cancer, where the clearly appropriate action to reduce lung cancer is to reduce smoking, and there is a demonstrable relationship between cigarette price rises and declining smoking rates. Obesity is multi-factorial condition; food intake is only one part of the problem.

And even if it can be argued that food intake is the MAIN part of the problem, there is no evidence that I am aware of to be certain that by raising the price of 'unhealthy' food you will switch people's preference to 'healthy' food; people may instead choose to consume fewer non-food goods to continue to afford the food choices that satisfy them. Lower-income households may just become poorer, not thinner.

Some thoughts in response to the article (not a critique, not expert opinion, not evidence based research, just brainstorming free form thoughts).

How about instead of taxing the end product (which won't prevent manufacturers from producing them) we tax the raw product. Now I know that is not realistic, but I am thinking about David Gillespie's thoughts on obesity... that the rise of obesity appears to be inversely correlated with the the price of sugar.

I doubt that we could do a long term study... but wouldn't it be interesting to increase the price of sugar, including derivatives (and in particular, high fructose corn syrup) to it's 1900 level. Manufacturers would probably stop using it knowing that the consumer won't be able to afford the end product. The consumer won't even have to choose between a mars bar and a snickers or can of coke. None of these will be available except the artificially sweetened variety (so maybe we should also tax the ingredients that make up sweeteners too).

No, I don't like that idea either, I like the freedom of choice and having icecream and chocolate when I want it, and in quantities I want, despite the ill effects it has on me.

But what will I cost the health system in years to come? I have no idea and I don't care to think that far ahead. Right now I feel fine and that works for me. I know the research... "but it won't happen to me". As horrible as it sounds, and as much as I won't like it, it may take an intervening govt with regulation of an extreme nature like a huge tax on sugar, and all it's derivatives and substitutes, that prevents the manufacture of the calorie-rich nutrient-poor foods, for me to lose weight.

I do not believe a tax on end products will work, based on knowledge of my own attitude and behaviour around food. They'll still be affordable although less so, and most likely I will choose to forego something else to have the sweet thing.... the fruit or that magazine, or delaying a bill for a while. It won't change my desires or behaviours in any noticeable way. It also won't stop manufacturers making these things... and I expect... just drawing from the milk wars... they'll find other ways to make the product cheaper to keep people buying.

While I know this is fraught with problems, I think the best way to reduce obesity is to reduce the availability of the things that make us fat. If we banned tobacco in Australia, we wouldn't have any smokers. Of course, apart from the outcry about freedom of choice and the manufacturers right to manufacture and sell, it may open the doors for black market and smuggling. Gosh, imagine if the penalty for bringing sugar into the country was the same as the penalty for bringing heroin into the country? Hmm, probably enough of the random brainstorming free thinking.

I personally think we don't yet know enough about the factors that lead to people becoming obese. I think it is unrealistic to be thinking about taxes and regulations until we know enough about what we should be regulating and taxing, regardless of whether we believe regulating and taxing would or wouldn't work.