Soda drinks are just 1.6% of average calories

In their report on the sugar tax, the Taxpayers’ Union stated that only 1.6% of average calories came from sugary soft drinks.

Now I’m on their board, but I don’t normally get into the details of research publications. I referred to the 1.6% figure, but I started to think that it must be wrong.

Surely no sensible group or person would advocate a tax on soft drinks, if they represent just 1.6% of calories? Could anyone (apart from those who just hate soft drink companies) really think a tax on products that produce just 1.6% of calories would achieve anything, while ignoring the other 98.4% of calories? So I started to doubt the 1.6% figure.

Hence I asked the NZTU staff if they could provide the data to back up the 1.6% claim. And they did. It is from the 2008/09 NZ National Nutrition Study of 4,721 NZers.

The NNS found that 9.9% of total energy intake (calories) comes from sucrose (added sugar). Of total sucrose intake 16% comes from non-alcoholic beverages.

Multiply 9.9% by 16% and you get 1.6%. So the figure comes from the official Ministry of Health nutrition survey.

So the proponents of a sugar tax want to tax something that represents 1.6% of the average calories consumed by NZers. They think this will make a material difference to obesity.

Let’s say that a sugar tax does lead to a 10% reduction in sales of soda drinks. This would see average calories reduced by 0.16%.

So what would be the average reduction in calories? 3.2 a day (off a 2,000 standard).

Now it takes around 9,000 fewer calories to lose 1 kg of weight. So how long would it take for an average weight loss of 1 kg with a sugar tax that reduced soft drink consumption by 10% (and generously assuming no substitution).

2,813 days.

That is around 7 and a half years.

So if you introduce a sugar tax on soft drinks, and it reduces sales by 10% (a generous assumption) and there is no substitution (an even more generous assumption), then in 7 and a half years we might all weigh one kg less.

The definition of obese is a BMI of over 30 and to not be overweight you need a BMI of 25 or less.

if you are average height male (177 cm) and have a BMI of 30.3 you’d weigh 95 kgs. To get a BMI of 25 you need to drop to 78 kgs – a drop of 17 kgs.

So a sugar tax that drop soda drink consumption by 10% and didn’t result in any substitution (highly unlikely) would take around 128 years to get an obese person to a healthy weight.

And for this, they want a new tax that would cost NZers billions and billions of dollars.