14 Apr 2017

The Cost of Sugar

From Featured Audio, 9:06 am on 14 April 2017

Professor Jim Mann, Dr Jacqueline Rowarth and Professor Tony Blakely join Kim Hill for a lively conversation about why free sugar is so bad for us, whether diet soft drinks help combat obesity and sugar versus fat.

So juice is not so healthy after all...

According to expert in obesity and diabetes Prof. Jim Mann from the University of Otago, not all sugars are the same.

The most important distinction he makes is between sugar which is intrinsic to what we consume, and the other kind - free sugar.

“By virtue of being surrounded by a cell wall,” he comments, “the sugar in unprocessed fruit and vegetables is much more slowly absorbed, and therefore better to consume, than the free sugar found in processed juice.”

Prof Tony Blakely, Dr Jacqueline Rowarth, Prof Jim Mann and Kim Hill

Prof Tony Blakely, Dr Jacqueline Rowarth, Prof Jim Mann and Kim Hill Photo: Billy Wong/University of Auckland

In addition, it’s very easy to drink far more sugar in juice form from a container or bottle than we would if we were consuming the fresh fruit.

“If you have a small glass of orange juice,” he says, “it comes from a whole lot of oranges.”

By contrast, he says, most people wouldn’t have more than one or two oranges at most at one sitting.

Despite the current fashion for juicing machines and the health-giving claims made on their behalf, Prof Mann sees no health benefit whatsoever in drinking vast quantities of juice.

The World Health Organisation recommends limiting intake of free sugar – the kind not naturally occurring in the things we eat or drink – to no more than 10% of total calories.

Given that many of us consume far more free sugar than that, what role do artificial sweeteners play in helping us hit that target?

Prof Tony Blakely

Prof Tony Blakely Photo: Billy Wong/University of Auckland

For epidemiologist Prof. Tony Blakely, swapping from a sugary drink to artificially sweet drinks still has benefit, since it reduces dental damage and the diabetes risk.

However, he says, the downside is that “you still retain that desire for sweetness. So it’s not the ideal solution.”

But it helps to minimise risk, and provides some support in allowing those whose palate has been shaped by a sugary diet to seek out and consume sweet things.

For that reason, he’s not in favour of taxes which target artificially-sweetened or low-sugar drinks as much as high-sugar drinks. He considers the hope behind such taxes – that consumers will be forced into a healthier diet because everything sugary they like is now more expensive – to be unrealistic.

Even though artificially-sweetened drinks maintain that craving for sweetness among those who consume a lot of them, they are still, he feels, a step towards better health.

And this nudge doesn't only affect the consumer. The food and beverage industry is also persuaded to support better outcomes which can then be built on in the future.

Prof Jim Mann and Kim Hill

Prof Jim Mann and Kim Hill Photo: Billy Wong/University of Auckland