Sweet slopes

Slippery slope arguments are only a logical fallacy if you don't have a mechanism. 

In health and lifestyle regulation, there are a couple of plausible ones. A rather plausible one is that establishing control regimes over consumption behaviours in one domain reduces the marginal cost of implementing similar control regimes over other consumption behaviours. Eugene Volokh covered rather a few mechanisms over a decade ago.

Here's Grant Schofield, the Ministry of Education's special health advisor and public health professor at AUT:

“[This Government] might not do a tax right away, but they can certainly start….with any of the points in our paper that we’ve suggested.”

Anti-tobacco laws over the years are used by Schofield and his co-authors to show the importance of Government intervention in making sugary foods less available and affordable in shops. Changes at the supermarket, ensuring sugary food and drink are not “loss-leading” and easy, end-of-aisle temptations, are among the recommendations.

Organisations providing dietary advice should also be banned from accepting money or endorsing products that market processed food, Schofield says. If they do accept or promote companies that have processed food, that should be publicly declared to show a conflict of interest. 

...

[Schofield] also points out that anti-sugar policies could be tacked on to current “infrastructure” restricting sale and advertising of alcohol and tobacco.

“We’ve got quite strict controls [over alcohol and tobacco sale]. I know people enjoy them, but they cause harm. It’s exactly the same with sugar and junk food.

“We already have all the infrastructure to do that with alcohol and tobacco, so let’s just chuck sugar in there as well.

Schofield also uses tobacco to rebut “industry arguments” regarding potential loss of business.

“At every point [when changes were made], there was interference. When smoking was stopped in bars and pubs, the industry… said it was going to be the end of everything and there would be people out of business. Actually the exact opposite happened. The country was just a better place.”

Overall, the public health problems stemming from excess sugar consumption are not too different from those associated with tobacco.

“You can say there is no safe level of tobacco, but there is a safe level of sugar,” Schofield admits.

“But there’s no nutritional value for sugar. I’m not saying we’ll ban it, it will still be in society, but we’ve got to change its availability - it’s pretty obvious.”

I care less about plain packaging on cigarettes per se than about the slope it puts us on. Remember what Jack Banzhaf told us about tobacco in the 90s?

"They use the 'slippery slope' argument. 'My God, if they can do this to smokers today they can do this to people who eat Haagen-Dazs ice cream or whatever.'"

Yup. They did. And they were right. Adjust your priors accordingly.

Bit depressing though. Wasn't it only a couple of months ago that NZIER and the Ministry of Health both advised that sugar taxes were a pretty bad idea?