Again, the focus of the ABC story was a former economist who gave up sugar and lost weight. Yes, I know, anecdotal evidence. And yes, if he had given up fat he would have lost weight too, or starch or alcohol. Cutting down on calories does induce weight loss. However, the man’s personal experience was with sugar and having been enlightened he apparently embarked on a mission to rid the Australian diet of the root of all evil.

But he had a problem: Australia’s leading expert on carbohydrates and health, Professor Jennie Brand-Miller from the University of Sydney, was not overly concerned about sugar. Her view was that health effects of carbohydrate-rich foods were related to their blood sugar-raising potential or glycaemic index. Viewed through this perspective, foods rich in refined starch, which strongly raise blood glucose, may be just as bad, or even worse, than foods rich in sugar. Despite considerable scientific support such permissive views on sugar could not be tolerated so a kind of fatwa was issued: Brand-Miller had to be beheaded, in a profession sense. And the ABC and the economist have been after her ever since.

Again, the latest program examined a paper written by Brand-Miller and Dr Alan Barclay called the Australian Paradox in which these authors observed that while obesity rates in Australia have climbed in recent decades, sugar consumption appears to have fallen. But why trawl through this paper again now? For goodness sake, it was published five years ago.

Journalistic deception

Had the public interest been Lateline’s key concern, the producer might have asked a simple question: have any new studies been published that might inform the issue? As it turns out, new studies have been published that relate to all three lines of evidence that Brand-Miller and Barclay relied on in their paper – national dietary surveys, apparent consumption of sugar data and soft drink sales. The results of all three of these new studies are consistent with a fall in per capita sugar consumption in recent decades.

I am very familiar with the two peer-reviewed papers as I co-authored them. If the ABC had been interested in presenting a balanced story they could have given me a ring, but no such luck. They know I exist because Lateline flashed my photo up on the screen on Tuesday night. And at least one of their senior journalists, who featured on the Lateline program, is familiar with the recent soft drink data because I sent it to her the last time the ABC was intent on misleading the general public about sugar. Unfortunately, the data were withheld from the general public on that occasion, as they were this time around.

There is a name for the practice of deliberately withholding information so as to promote a view that a journalist knows to be incorrect. It’s called journalistic deception.

What about the ABS?

If the ABC didn’t want to talk to me at least they could have interviewed someone from the Australian Bureau of Statistics (ABS) which conducted the latest national dietary survey. The top line results from this study indicate a fall in the intake of total sugars since the 1995 survey, though better insight is on the way. The ABS has been busily analysing their data in depth, teasing out ‘added sugar’ from naturally-occurring sugar, and the results are due out in a fortnight.

Why didn’t the ABC interview the ABS? Or just wait a couple of weeks for the release of the in-depth analysis? Why construct a story with stale, 5-year old news that had been covered before when a real story, backed by strong new evidence, will present itself in a couple of weeks? Maybe Lateline got wind of the results.

Furious agreement

In lieu of balance, Lateline interviewed six experts who all agreed with one another – shades of the infamous Catalyst programs on cholesterol. The Australian nutritionists interviewed essentially argued that they just don’t believe the available data on sugar intake. They couldn’t highlight any other sugar consumption studies, it was just a case of ‘spare me the evidence; my mind is made up.’ Such is the parlous state of public health nutrition in Australia that some of its senior players are prepared to advocate policy based on denial of the scientific evidence.

Tellingly, the two authors of the Paradox paper, the editor of the nutrition journal that published it, the professor from the University of New South Wales who reviewed the complaint about the Paradox paper and the Vice Chancellor of the University of Sydney all declined to be interviewed by Lateline. It would appear that the ABC’s reputation for bad nutrition stories had preceded it.

What are the motives?

I suspect those who pitched the story to the ABC were intent on discrediting Brand-Miller and Barclay one more time before the release of the comprehensive ABS analysis of sugar in the Australian diet. These new data will find their way into the updated version of the Australian Paradox paper, which was required as part of the review of the complaint against its authors. With all key lines of evidence likely to show no parallel between sugar intake and obesity trends it would appear that Brand-Miller and Barclay’s argument will prevail. The media strategy seems to have been to hit them while they are still vulnerable.

But why would Lateline accept such a poisonous pitch? What’s in it for the ABC? Surely there is not much journalistic kudos to be gained from recycling old stories.

My guess is that the ABC shares the interest in ‘food politics’ of many of the more radical public health nutritionists, with its strong anti-corporate sentiment. This requires that the food industry be attacked at every available opportunity – sugar being the current weapon of choice. No doubt the next objective is the imposition of a tax on sugar-sweetened beverages but if this particular battle is to be won sugar has to be seen as a BIG health issue, even though it isn’t. The public relations people call this ‘perception management’.

Personally, I would have thought that the ABC’s role was to report on food politics rather than engage in it.

Disclaimer:
This article reflects my personal views. It was not commissioned or paid for by anyone.

That’s an interesting claim but is it true?

Actually, it’s a strange measure to have chosen as it is almost impossible to verify. Most countries in the world simply don’t have good dietary data on teenagers, or adults for that matter. Let’s look at the available data and consider whether the claim is close to being right.

Any global average for sugar intake will be greatly influenced by typical intakes in populous countries such as China, India and Indonesia. Yet sugar intakes in these countries are very low – of the order of 20 grams per day or less, which equates to a miserly 4 teaspoons of sugar per day.

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Added sugars or total sugars?

The figure used in That Sugar Film may have been referring to total sugars i.e. the naturally occurring sugars in fruit and milk plus ‘added sugars’. I’m not sure why anyone would be concerned about naturally occurring sugars but let’s push on.

Intakes of total sugar in China, India and Indonesia would be more than twice that of added sugar, maybe 10-12 teaspoons a day. If we assume that teenagers in these countries consume more sugar than everyone else their intake could be about 12-16 teaspoons a day. That’s still a long way from 40.

American sweet-tooths

One populous country stands out from the rest when it comes to sugar intakes – the United States, which fortunately has good dietary data. Sugar intake in the US appears to have peaked in the early 2000s and has been falling since, largely driven by falling intakes of sugary soft drinks.

Currently, adolescents in the US consume about 18 teaspoons of added sugar each day or about 28 teaspoons of total sugars. The makers of That Sugar Film chose to use a level teaspoon (4.2g) as their chosen measure rather than the usual 5g teaspoon, which inflates the intake up to about 33 teaspoons a day – still well short of 40.

So the figure for sugar consumption chosen for That Sugar Film was nothing like ‘just slightly more than the average teenager worldwide’.

Sugar intakes of Australian teenagers

For the record, the average Australian aged 14-18 years consumes about 24 teaspoons of sugar a day, about half of which occurs naturally in fruit and milk.

Had the makers of That Sugar Film consulted with someone who actually knew what they were talking about they would have avoided misleading their audience. Then again, perhaps that was the idea.

Views on the health impact of sugar and carbohydrates more generally differ quite widely and there is plenty of room for debate, but it needs to be informed debate. Wild overstatements don’t help and diminish the credibility of those who make them.

WHO’s record on sugar

The World Health Organization (WHO) is a leading global health agency with a proud history of sound dietary advice, including advice about sugar. In a 1990 report, WHO recommended a limit on intake of ‘free sugars’ of no more than 10% of daily calories, which is about the current average intake of Australian adults. Free sugars means all sugars added to foods by the manufacturer, cook or consumer, plus sugars in honey, fruit juices and syrups.

WHO’s rationale for limiting sugar intake was to lower the risk for tooth decay. No lower limit on intake of free sugars was recommended.

Thirteen years later WHO again looked at the science of sugar and health and found ‘convincing’ evidence that both the amount of free sugars and the frequency of sugar consumption increased the risk for tooth decay. And again WHO recommended a limit of 10% of daily calories.

The 2015 WHO report

In its latest report WHO found … wait for it … that eating too much sugar causes tooth decay and that the intake of free sugars should be limited to … wait for it … less than 10% of daily calories.

Interestingly, WHO also made a ‘conditional recommendation’ that the intake of free sugars could to be lowered to below 5% of daily calories for better prevention of tooth decay. But then WHO stated that this recommendation was based on ‘very low quality evidence’.

In this day and age it is a mystery why any health organisation would make a recommendation based on ‘very low quality evidence’. If the evidence is so poor, why didn’t WHO just stick with the old advice that there was no recommended lower limit on intake of free sugars?

WHO also reviewed the evidence in relation to whether sugar intake is related to body weight. Its recommendations are cautious e.g. WHO states that the evidence ‘suggests’ an association between reduction of free sugars intake and lower body weight in adults. There was no association in children. The quality of the evidence varied between moderate to low.

Perhaps the reason for the soft recommendation was WHO’s desire to maintain advice about free sugars, whereas other organisations have tended to focus more on sugar-sweetened beverages where there is more persuasive evidence. WHO found that substituting sugar for other carbohydrates (starch) had no effect on body weight, so there is nothing inherently fattening about sugar – it all depends on how many calories you eat.

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The myths: what WHO doesn’t say

The latest WHO report is notable for what it doesn’t say about sugar. It doesn’t say sugar is addictive, toxic, uniquely fattening, or that it gives you fatty liver, heart disease or diabetes. That’s because these are all just myths peddled by attention-seeking, non-nutritionists to boost their celebrity, sell books and make money.

Too much sugar is bad for your teeth. And sugar contains calories, which cause weight gain when consumed in excess of the body’s needs.

It’s not rocket science; it’s nutrition science.

The origins of the low fat diet

The low fat diet had its origins in 1980 with the publication of the first Dietary Guidelines for Americans. The recommendation to ‘Avoid too much fat, saturated fat and cholesterol’ was intended to lower blood cholesterol and reduce the risk for heart disease. Although the focus was really on lowering saturated fat, it was thought that lowering total fat intake may help prevent some cancers and obesity.

In Australia, the simpler guideline ‘Avoid eating too much fat’ was adopted to aid its communication.

Keys versus Yudkin

The low fat diet had a low key launch. Yet these humble origins are now being re-imagined as the disastrous consequences of a fight to the (professional) death of two of the great nutritionists their era – Ancel Keys and John Yudkin. As an epidemic of heart disease raged in the post-war years Yudkin pointed his finger at sugar. But Keys argued that the effect of different fats on blood cholesterol was the key mechanism affecting heart disease risk, and he won the day.

Yet Keys’ victory is now being portrayed as the fateful moment when nutrition science careered off course for four decades. Fortunately for humankind, ‘the truth’ that the problem was sugar all along has now been revealed by various journalists, lawyers, economists and B-list celebrities, all of whom seem to have made a packet in doing so.

Not content with challenging Ancel Keys’s views, the myth-makers have set out to destroy his reputation, arguing that he fudged his data – that Keys was a fraud. In contrast, Yudkin is now portrayed as a prophet, whereas he was discredited in his day.

The mythical fork in the road

Why the myth-makers need to construct this fanciful sugar or fat fork in the road is a mystery. After all, both the Australian and the American dietary guidelines published in the early 1980s discussed fat and sugar. The relevant sugar guideline in Australia was ‘Avoid eating too much sugar’ and the American guideline simply said ‘Avoid too much sugar’. And the advice to limit sugar intake has stayed in place ever since.

In contrast, as new scientific evidence about fat became available the cancer link was dismissed and recommendations steadily evolved to have more focus on fat type and less on lowering total fat. All the recent research is ignored by the myth-makers.

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Mistakes were made

Certainly, mistakes were made by some of our health authorities. By the mid-90s the ‘eat less fat’ message should have been disappearing into history. However, it was given a new lease of life when obesity experts latched onto it, based on insufficient evidence which soon fell away.

According to the myth-makers, this wasn’t a policy failure. No, it was the work of the sugar barons conspiring with their operatives in academia to prop up the low fat diet to further their commercial interests!

Fraud? Conspiracy?

Alternatively, maybe nutrition experts have just been gradually refining their dietary recommendations as new scientific evidence becomes available.

In 2011, Professor Jennie Brand-Miller from the University of Sydney and Dr Alan Barclay, Chief Scientific Officer at the Glycaemic Index Foundation and Head of Research at the Australian Diabetes Council published a paper on the Australian Paradox – the apparent fall in sugar consumption that occurred over a period when rates of obesity in this country increased. The paper was obviously intended to stir the pot a little.

The narrative in the United States at the time was that the increase in obesity prevalence in that country had coincided with increasing sugar intake, so perhaps sugar was a causative factor. In their paper Barclay and Brand-Miller pointed out that while that may well be the case in the United States, sugar intakes had remained fairly constant in the United Kingdom over the same period and had actually fallen by 16 per cent in Australia. However, both countries had experienced an increase in rates of obesity, hence the Australian Paradox.

Under normal circumstances this simple paper may have dissolved away into the vast ocean of scientific literature and never been heard of again. However, a member of the public took exception to the finding that sugar intakes in Australia were falling. Despite not having any qualifications in nutrition or science he had formed a view that sugar intakes in Australia were in fact rising. A social media campaign was initiated to attack the nutrition researchers and their findings and a formal complaint was lodged with the University of Sydney.

The accusation

It was alleged that Barclay and Brand-Miller deliberately included falsified data in their analysis, were reckless, caused harm or risked public health and gained personally from their conduct. For nutrition research scientists the accusations could not have been more serious. After all, the researchers were required to adhere to the University of Sydney Research Code of Conduct and the Australian Code for the Responsible Conduct of Research. If they were found to have breached these codes their respective careers in research were finished.

The investigator

The University of Sydney took the complaint seriously and decided that an internal enquiry may not have been sufficient to resolve the issue. An external, independent person of recognised high academic standing and with substantial experience in overseeing matters of ethics and integrity was sought to conduct the review. Professor Robert Clark AO, Chair of Energy Strategy and Policy at the University of New South Wales, Former Chief Defence Scientist of Australia and CEO of the Defence Science and Technology Organisation accepted the role. His 86-page report has just been released after a six-month inquiry.

The findings

The University of Sydney summed up the key findings of the report in its press release:

• A formal inquiry into allegations brought against a University of Sydney academic and her research collaborator has found no research misconduct occurred.
• There was no breach of the University’s research code of conduct or of the Australian Code for the Responsible Conduct of Research.
• Consequently, there is no basis for further investigation and the allegations have been dismissed.

Although the nutrition researchers must be relieved by the findings of the review we can only imagine what it was like to suffer the sustained attack on personal and professional integrity they had to endure. Professor Clark’s comments in the body of the report provide some insight:

It is my view that, at interview, Professor Brand-Miller and Dr Barclay presented as open, honest, and well-intentioned academics … The stress resulting from the impact of the Complainant’s allegations on their scientific integrity was apparent. They each expressed the view that over the past few years they had effectively undergone ‘trial by internet’ due to the manner in which the Complainant had aired the allegations in the public domain.

An inconvenient truth

Was all this really necessary?

It would appear that Barclay and Brand-Miller were targeted because they were generating data that undermined the sugar scare being perpetuated by various media personalities, celebrities and booksellers, who presumably were on a nice little earner. To sustain the sugar scare there had to be a crisis –a tsunami of sugar crashing across Australia wreaking havoc on the population’s health. Evidence that sugar intake was actually falling simply represented an inconvenient truth that had to be buried, along with the nutrition scientists who dared to publish it.

Science is all about a contest of ideas – debate between differing views is inherent in the process. But the place for such arguments is in scientific meetings or in peer-reviewed journals where dissent can be recorded for posterity. But fundamental to such debates is soundly based scientific evidence, civility and respect for one’s opponent.

Sadly these were missing in the attack on Brand-Miller and Barclay.

The trend in sugar consumption in Australia has been a contentious issue in recent years, especially as nutritionists and lay people have sought dietary explanations for the obesity epidemic. On one side of the argument is the view that the intake of sugar, or perhaps fructose, has increased in recent decades and that this has been the driving force behind the epidemic. This argument emerged in the United States where sugar intakes are undoubtedly high.

In the Australian context it has been argued that sugar intake hasn’t increased at all and is actually in steady decline. Proponents of this argument include Dr Alan Barclay and Professor Jennie Brand-Miller who published an assessment of trends in intakes of sugars and obesity rates in Australia, the United Kingdom and the United States between 1980 and 2003. In this paper the authors identified an ‘Australian Paradox’ – increased rates of obesity despite an apparent fall in sugar intake.

The recent publication of new data from the Australian Health Survey (AHS) has provided some clarity on this issue.

Sugar data from the Australian Health Survey

The AHS was conducted by the Australian Bureau of Statistics, which also conducted Australia’s last national dietary survey of adults and children in 1995, so now we have insights into how the diet of Australians has changed over the intervening period of approximately 16 years. Here are some of the top-line results relating to sugar.

• Intake of total sugars has fallen in men, women and children.
• The percentage of dietary energy from total sugars has also fallen.
• Carbohydrate intake has fallen, both in absolute terms and as a percentage of energy. Total energy intake has also fallen.

Sugar from soft drinks

The percentage of sugar from coming from soft drinks has fallen substantially:

• In men it fell from 15.5% of the total in 1995 to 11.4% in 2011 – a fall of 26%.
• In women it fell from 9.3% to 7.6% – a fall of 18%.
• The proportion of sugar from fruit drinks, vegetable drinks and cordial was up marginally in men but down substantially in women.

Sugar from other food groups

• Milk products provided over 17% of total sugar intake.
• Fruit provided about 16% of sugar intake (or 23% if fruit drinks are included). The percentage of sugar coming from fruit has increased.
• Breakfast cereals provided just 2.8% of sugar intake. The percentage of sugar coming from breakfast cereals has fallen.
• The proportion of sugar coming from cakes, muffins, pastries, biscuits, etc has increased. It’s the same story with confectionery.

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Sugary drinks

I was particularly interested in the data on sugary drinks, having recently published a paper on the topic. Our dataset was very different to that of the AHS, comprising sales data from industry, but the timeframes were similar. In our study we found a fall in the sugar contribution from carbonated soft drinks from 8.4 kg per person in 1997 to 6.2 kg per person in 2011. In relation to the broader category of sugar-sweetened beverages, per capita sugar contribution fell over the 15-year period from 9.2 kg to 7.6 kg. These results are consistent with the large falls in the percentage of sugar from coming from soft drinks observed in the AHS.

Calories from ‘discretionary’ drinks

The AHS also provided data on how many calories came from ‘discretionary’ foods and drinks i.e. those that are not providing many essential nutrients. Here are some figures for beverages:

Soft drinks 1.8%
Fruit drinks, cordials 1.2%.
Alcoholic beverages 6.0%

It makes you wonder why so much of the current anti-obesity effort is being invested in relation to nutrient-poor soft drinks and so little attention is being applied to the much bigger issue of nutrient-poor alcoholic beverages. The percentage of calories coming from alcohol increased between 1995 and 2011.

Is there a Paradox?

The argument about whether sugar intake in Australia is going up or down is now resolved – sugar intake has clearly fallen since 1995. Whether declining sugar intake coinciding with rising obesity prevalence represents a paradox or not depends on your beliefs. If you are convinced that sugar intake is the primary driver of obesity then indeed there is a paradox that you will need to explain somehow. According to your thesis obesity rates should be falling not rising. But arguing that the data on sugar consumption are all wrong is no longer good enough.

The sugar scare: driven by non-nutritionists

The current sugar scare may have had its genesis in the American experience and the credible hypotheses it generated. But before these hypotheses could even be adequately tested in good scientific studies the agenda was hijacked by opportunists, self-serving activists, book-sellers, B grade celebrities and shameless self-promoters, aided and abetted by a media that cares a lot about ratings but little for facts or science. In Australia, the whole premise of the scare – that sugar intake is rising – has been shown to be false. Consequently, the community has been alarmed about a major problem that doesn’t actually exist.

Unfortunately, non-nutritionists operating in the lucrative dietary advice business don’t understand the potential for negative nutritional outcomes from the simplistic solutions they offer. A scientifically-trained dietitian or nutritionist would understand that a sizable proportion of sugar in the diet comes from nutrient-rich fruits and milk products and would offer nuanced advice around sugar, aimed at lowering intake of nutrient-poor foods. In their wilful ignorance the non-nutritionists just target sugar wherever it can be found and sod the consequences.

In the United Kingdom, Professor Graham MacGregor, Chairman of Action on Sugar, recently lamented that the field had been overtaken by ‘nutters’ whose exaggerated claims were generating hysterical headlines. It’s a familiar scenario.

The question for dietitians and nutritionists is how to take back control of the agenda from the nutters. Any ideas?

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Obesity is proving to be an intractable public health problem demanding innovative solutions and one idea that is attracting attention is the taxation of sugar-sweetened beverages. The theory is simple enough. Basic economics tells us that if the price of sugary soft drinks were to rise, their consumption would fall; lower intake should mean lower calorie intake which would lead to lower body weights. But would it work in practice?

The Ohio experience

A recent research study conducted in the United States provided some interesting insights. Taxing soft drinks has a long history in the US and occurs in many states today, though historically the rates have been low and the purpose has been to raise revenue. But there was an interesting exception. In 1992, the state of Ohio introduced high taxation of sugary soft drinks which was then repealed at the end of 1994. This provided an opportunity to test the effect of taxation of soft drinks on body weights over a period of two years. The researchers compared changes in body weights in Ohio over this period to (1) all other states that had no increased taxation and (2) a bundle of states with the same mean BMI as Ohio. The researchers found:

… very little evidence that the large tax imposed in Ohio had any detectable effect on population weight … our results cast serious doubt on the assumptions that proponents of large soda taxes make on its likely impacts on population weight.

How come? Why didn’t quite high taxation of sugary soft drinks affect body weights?

How strong is the evidence that soft drinks affect body weight?

It may come as a surprise to many dietitians and nutritionists that there is actually a debate in the scientific literature about whether lowering intakes of sugar-sweetened beverages would reduce the prevalence of obesity. Two excellent papers published in Obesity Reviews last year presented the opposing views.

In one corner was Professor Frank Hu from the Harvard School of Public Health who argued that the issue of whether sugary soft drinks are linked to body weight has been resolved and the answer is yes. In developing his argument Professor Hu first drew on epidemiological studies, citing a Harvard meta-analysis of cohort studies. It has to be said that the association between sugar-sweetened beverage consumption and body weight in children in this study only just reached statistical significance, though an updated meta-analysis by the same research team is also supportive.

The second line of evidence considered was randomised controlled trials, which would be expected to provide better insight but these were relatively few in number and their findings were conflicting. However, Professor Hu was swayed by two recent high quality trials by Ebbeling et al and de Ruyter et al both of which indicated that sugary drinks affect body weight.

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The alternative view

The alternative view was presented by a team headed by Professor David Allison from the Nutrition Obesity Research Centre at the University of Alabama. Their view was based on data from their updated meta-analysis of randomised controlled trials, which included the two recent trials by Ebbeling et al and de Ruyter et al. Again the trial evidence was equivocal. On the one hand, adding sugar-sweetened beverages to subjects’ diets was linked to increased body weights, but lowering intake of these beverages did not lower body weight, except in overweight subjects. However, these authors noted that the recent high quality trials were ‘tilting the needle’ in favour of an association.

The effect size is small

One thing that had never really registered with me was how small the ‘effect size’ of sugar-sweetened beverages on body weight really is. The authors explained it thus:

Increasing consumption of [sugar-sweetened beverages] explains 1.92% of the variance in body weight or BMI change. Reducing consumption of [sugar-sweetened beverages] in persons of all weight categories explains 0.09% of the variance in body weight or BMI change. Among persons who are overweight or obese at baseline, reducing the consumption of [sugar-sweetened beverages] explains 1.54% of the variance in body weight or BMI change.

So although the consumption of sugar-sweetened beverages appears to be linked to body weight the magnitude of the effect is tiny.

Is substitution a factor?

One of the key assumptions of the taxation strategy is that the higher cost of sugary soft drinks would result in lower intake of these beverages and lower calorie intake. In other words, there would be no substitution with other calorie-containing drinks or foods. This may well be the case in the constrained environment of a randomised controlled trial but would it happen in real life?

A study in 2010 found that although taxing soft drinks resulted in a small fall in soft drink consumption this was completely offset by increases in consumption of other high calorie drinks, such milk-based drinks. Consequently there was no effect on total calorie intake at all. Although most nutritionists would be glad to see nutrient-rich beverages replacing nutrient-poor drinks in children’s diets, this is not the intended purpose of an obesity tax.

Could taxation be made to work?

If taxation is to work as a strategy for obesity prevention it may be worthwhile revisiting the 2011 study by Mozaffarian and colleagues which looked at which foods and drinks were associated with weight gain over time. The surprising findings of this study, which considered three large cohorts of men and women, were that just about every group of foods and drinks was associated with weight gain, positively or negatively.

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Although sugary soft drinks were positively linked with weight gain, so were fruit juice, potatoes, potato chips, red meat, processed meats, sweets and desserts, butter and refined grains. Rather than tax just one of these, an effective strategy for obesity prevention would probably need to tax them all. As nuts, yoghurt, fruits, vegetables and wholegrains were all negatively associated with weight gain an effective taxation strategy would also need to lower the price of these relative to the ‘fattening foods’ and also those foods with an apparently neutral effect.

Although it sounds complicated it might work. But would the Federal Treasury ever support such an approach?

Despite all the interest in sugar in recent years Australian nutritionists don’t really know for sure whether sugar intake in Australia is going up, going down or staying the same. Unlike American nutritionists who have the findings from the ongoing NHANES series of nutrition surveys to go on, we have been hamstrung by the poor quality of our nutrition data. There are few national nutrition surveys to guide us.

In 2011, Dr Alan Barclay and Professor Jennie Brand-Miller collated the available Australian data and concluded that per capita consumption of sugar had decreased by 16% in Australia between 1980 and 2003. Their work was attacked with uncommon vigour. Apparently, this was not a message that some people wanted to hear. One concern expressed about their work was that Barclay and Brand-Miller had partly relied on ‘apparent consumption’ data, which the Australian Bureau of Statistics ceased publishing in 1998/99.

In a subsequent analysis by the commodity firm Green Pool, the apparent consumption data were updated and analysed, and again suggested a long-term fall in sugar consumption in Australia was underway. There were more howls of protest. Unfortunately, when the quality of the available data is ordinary this sort of debate ensues and we end up with lots of heat but little light.

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Soft drink trends

Carbonated soft drinks have been a major source of sugar in the Australian diet for decades. In 2007, Dr Gina Levy and Professor Linda Tapsell published an analysis of sales of soft drinks and other water-based beverages in Australia between 1997 and 2006. There were three key findings – beverage sales were increasing; there was a shift away from sugar-sweetened to non-sugar drinks; and the per capita contribution of sugar from these beverages to the national diet was declining.

But have these beverage trends continued to the present day?

New soft drink study

Recently, Gina Levy and I conducted a study to update the earlier findings of Levy and Tapsell. Our objective was to assess trends in sales of soft drinks and other water-based beverages over a 15-year period, from 1997 to 2011. The paper has been accepted for publication in Nutrition & Dietetics and should be available as an ‘early view’ soon. Gina Levy presented the findings at the ‘Sweet Symposium’ in Sydney on 2 December.

Sugar contribution from sugar-sweetened beverages

The most interesting finding from this study was the fall in the sugar contribution from carbonated soft drinks from 8.4 kg per person in 1997 to 6.2 kg per person in 2011. In relation to the broader category of sugar-sweetened beverages, per capita sugar contribution fell over the 15-year period from 9.2 kg to 7.6 kg.

The reason for the decline in the contribution of sugar from these beverages is the ongoing, long-term decline in the proportion that is sugar-sweetened, from 70% to 58% of the total. This is largely driven by a substantial shift in carbonated soft drinks from sugar-sweetened to non-sugar drinks. Over 15 years the proportion of carbonated soft drinks that is sweetened with sugar has fallen from 64% to 45% of the total. There has been a corresponding increase in the proportion of non-sugar soft drinks and still water.

Factors affecting soft drink purchase

The traditional drivers of the soft drink market have been indulgence and convenience. It now appears as though increasing health consciousness, especially in relation to body weight, is making its presence felt.

Disposable income appears to be critical to soft drink purchases – middle to high-income families purchased more carbonated soft drinks than lower income families. And, over time, lower-income families purchased a smaller proportion of both sugar-sweetened and non-sugar carbonated soft drinks. I was a bit surprised by this, half expecting lower income groups to be less aware of health issues and more likely to consume soft drinks.

In the various income categories, the households with the highest purchases of soft drinks were those with teenage children, especially boys, and these guys like the sugary stuff. Researchers may like to investigate what drives the high intake of sugar-sweetened drinks among teenage boys. Is it increased energy needs? Or rebelliousness? Whatever it is, it doesn’t seem to lead to a life-long desire for sweetened drinks, as is often assumed. Beverage habits don’t last a lifetime – they change and evolve. In older households soft drink purchase is lower and there is a higher preference for non-sugar beverages.

Where to from here?

Whether you see sugar per se as a health problem or, like me, see the health issues associated with sugar-sweetened beverages as stemming from their ‘empty calories’ and glycaemic load, the long-term trends at play are good news and consistent with public health objectives. The water-based beverage category is undergoing a fundamental shift from sugar-sweetened to non-sugar drinks, a trend that has now been underway for at least 15 years.

A question for nutritionists to think about is: how can we support and facilitate this trend in favour of non-sugar beverages?

Importantly, how can we remove some of the barriers that stand in the way? One obvious barrier is the general public’s lingering concern about the safety non-nutritive sweeteners used in beverages. This concern is often whipped up by well-intentioned yet misguided food activists. Is demonizing a logical alternative to sugar-sweetened beverages a wise move?

Maybe it’s time to look at the big picture.

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John Sievenpiper knows a fair bit about dietary carbohydrates and health. His team in Toronto recently conducted systematic reviews and meta-analyses evaluating the effects of fructose on body weight, blood pressure and glycemic control in humans. He discussed some of the findings at the ‘Sweet Symposium’ on 2 December.

The fructose-centric view

Sievenpiper reviewed the rapid evolution of what he called the ‘fructose-centric view’ in modern nutrition, which positions fructose as a central driver of the obesity epidemic and cardiometabolic risk. Certainly several lines of evidence had raised suspicions about fructose – apparent increases in fructose consumption were associated with increases in obesity in population studies; animal studies showed fructose had adverse metabolic effects; there were similar findings in some human studies; and an articulate anti-fructose champion, Robert Lustig, emerged and took his simple ‘fructose is toxic’ message to the general public. And the media loved it – even the ABC’s ‘science’ program Catalyst jumped on the bandwagon and pushed the idea around. In less than a decade the fructose hypothesis became an anti-fructose doctrine with a chanting chorus of true believers.

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Concerns about the fructose hypothesis

Sievenpiper outlined several concerns he had about the fructose hypothesis. The first was the emphasis that had been placed on epidemiological links between the consumption of high fructose corn syrup and the increasing rates of obesity in the United States. Such associations are low quality evidence.

Also, the apparent link between increasing fructose intake and obesity rates was an American phenomenon. Sievenpiper noted the Australian Paradox i.e. rising obesity rates against a background of falling intakes of sugar, and there were similar paradoxes in the United Kingdom and Canada. A recent American Paradox had also emerged – falling intakes of sugar among children and younger adults in the US between 1999 and 2008, yet little or no reduction in dietary energy intakes. A plethora of paradoxes.

A second concern was the over-reliance on animal data when describing the metabolic effects of fructose. And the amount of fructose fed in some of the animal studies was exceedingly high – up to 60% of calories and therefore way beyond the amount typically consumed by humans (about 9% of calories in the US diet).

Sievenpiper’s third concern was that many of the human studies failed to fully account for the confounding effect of dietary energy. If feeding someone excess calories in the form of fructose produces metabolic disturbances, what’s the core problem? Is it the fructose, or is it the excess calories?

Fructose and cardiometabolic risk

The fructose-centric view states that ingested fructose ‘turns straight to fat’ i.e. fructose is rapidly taken up by the liver and converted to triglycerides, thereby contributing to fatty liver, insulin resistance and increased triglyceride levels in the blood. This may be what happens in rats but it’s different in humans – most dietary fructose (about 50%) is converted to glucose and ends up in the circulation, and another 15% or so is stored in glycogen. A further 25% is converted to lactate, so only a minor portion of ingested fructose (1-3%) is converted to fat in human beings.

To tease out the effects of fructose and excess calorie consumption Sievenpiper reviewed two types of human studies – ‘substitution’ trials in which the effects of fructose were assessed with total calorie intake held constant, and ‘addition’ trials in which extra calories in the form of fructose were added to diets. The addition trials observed higher body weight, higher triglycerides, higher total cholesterol, more fatty liver and higher uric acid levels – all the bad things that fructose is supposed to do.

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But the substitution trials painted a very different picture – none of these problems was evident and there was even a suggestion of benefit of fructose in relation to blood pressure and glycaemic control.

The conclusion that Sievenpiper drew from this work is that the addition trials show … effects which appear more attributable to the excess energy than the fructose itself. In relation to the obesity epidemic he argued that … attention needs to remain focused on reducing overconsumption of all caloric foods. Lower calorie intake to control body weight? What a radical idea!

Robert Lustig has argued that fructose is bad but glucose is good and should replace fructose where possible. Sievenpiper cited a recent review by David Ludwig that addressed this proposition directly. And the answer:

… the recommendation to replace fructose with glucose lacks an evidence basis. Rather, public health efforts should focus on reducing intakes of all highly processed carbohydrates, not just refined sugar.

‘Highly processed carbohydrates’

Ludwig doesn’t distinguish between refined sugar and refined starch; he bundles them together as ‘highly processed carbohydrates’. Sievenpiper cited a recent systematic review of 25 controlled trials supporting this view that concluded:

… it would appear that a moderate dietary sucrose intake at levels up to 25% of energy appears to have no significant adverse effects on lipid or carbohydrate metabolism in normal healthy adults when substituted for starch …

These findings are not new – they are consistent with those of the Institute of Medicine in the US and the European Food Safety authority that were discussed in an earlier post. But they beg the question: if substituting refined sugar for refined starch in diets up to the quite high level of 25% of energy has no significant health effects why do our nutrition authorities continue to use sugar or added sugar as a criterion for assessing the nutritional quality of foods and diets?

The last word

The fructose doctrine suggests that many of our dietary ills stem from just 8-9% of daily calories contributed by fructose. The real problem – highly processed carbohydrates – is much bigger than that.

Further reading

If you are looking for more insight into John Sievenpiper’s views on fructose check out his interview with American science writer David Despain.

Two new studies recently published in the New England Journal of Medicine have shed further light on the issue of soft drinks and weight gain.

Two new soft drink studies

Ebbeling and colleagues studied 224 overweight and obese adolescents who regularly consumed sugar-sweetened soft drinks. Half the subjects participated in a 1-year program designed to decrease consumption of these beverages. Both this intervention group and a control group were followed up for a further year after the intervention was complete. After one year the mean body weight of those in the intervention group was significantly lower (1.9kg) than that of the control group, though significance was lost at two years. So the program worked while underway but its effects did not persist.

The second study by de Ruyter and colleagues involved 641 primarily normal-weight children aged 5-12 years. Over an 18-month period half the children drank a sugar-sweetened soft drink each day; the other half drank an artificially sweetened soft drink. As these were growing children, body weights increased in both groups but those taking the sugar-sweetened soft drink gained a kilogram more than those drinking the artificially sweetened beverage.

Taken together, these studies suggest that sugary soft drinks may indeed increase the likelihood of weight gain. But why is it so?

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Liquid calories and energy balance

One of the mysteries of modern nutrition is how anyone manages to maintain normal weight in our superabundant food environment. Despite very different diets, food intake varying from day to day and the vast number of calories in and out each year, most people manage to get the balance almost right. Energy intake is fairly tightly controlled by the sensations of hunger, satiation and satiety. When energy intake is too high or too low these sensations adjust to control energy intake. Yet the system of adjustment and compensation seems imperfect when it comes to sugar-sweetened soft drinks.

The main hypothesis explaining this phenomenon is that calories in liquid form do not trigger the same satiety response as calories from solid foods (see Malik 2010), so the compensation for liquid calories is incomplete allowing overconsumption of energy. But is this a reasonable explanation? Aren’t stomach contents liquid? Why would the solid or liquid form of a food outside the body have an effect once the foods are sloshing around in your tummy?

What about milk?

In the best study so far linking individual foods to future weight gain Mozaffarian and colleagues showed that most calorie-containing beverages were associated with future weight gain, including sugary soft drinks, fruit juice and alcoholic beverages. But there was one notable exception – milk. Both whole milk and low fat milk were not associated with weight gain.

Effects on satiety may be the key. A West Australian study published a few years ago looked at how consuming fruit juice and skim milk affected satiety. Even though the volume and calories of the milk and juice were exactly the same, subjects found the milk to be more satiating than the juice. And calories consumed at a subsequent meal were lower after the skim milk.

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Is it the protein?

Soft drink, fruit juice and skim milk are all liquids and they all contain sugar so what explains the very different effects of these beverages on satiety and weight gain? It is tempting to think that the answer is protein. Some years ago Professor Steve Simpson from the University of Sydney proposed the Protein Leverage Hypothesis which suggested that dietary protein was the key to understanding the obesity epidemic and how it could be addressed. Based on extensive evidence from other species Simpson proposed that human appetite was not driven energy requirements alone: we ate to a protein target.

According to the hypothesis, if the available diet is relatively protein-rich the target for protein will be met well within caloric requirements, satiation will occur and eating will stop. This would explain the apparent benefits of higher protein diets for weight management. On the other hand, if the diet is rich in carbohydrate and fat but low in protein people need to eat a lot of food before meeting the protein target and they will tend to over-consume energy. Seen through this prism the problem with soft drinks is their lack of protein when compared to beverages such as milk.

Liquid meal replacements

Since we are discussing sugar-sweetened beverages and body weight, it is worth remembering that the evidence in favour of liquid meal replacements for the management of body weight is quite strong. A meta-analysis of six studies has shown that weight reduction using meal replacements was more effective than weight reduction using a conventional calorie-reduced diet.

Typically, liquid meal replacements are sugar-sweetened milk drinks. Again, being a caloric liquid or in this case a sugar-sweetened liquid, did not seem to pose a risk for obesity. On the contrary, the milk base of these products appears to offer a benefit.

Presence of harm or absence of goodness?

Nutritionists are conditioned to assess foods and drinks in terms of their sugar content and to pass negative judgement when ‘added sugar’ is present. But how are we to interpret evidence that sugar-containing beverages may be positively or negatively associated with weight gain, or neutral? Frankly, a focus on the sugar content of these beverages explains nothing.

Rather than sugar being an obesogenic agent or liquid calories being a problem, doesn’t the evidence suggest that the key issue is the presence or absence of essential nutrients, especially protein? Wouldn’t this explain why nutrient-poor soft drinks are less satiating and more likely to be associated with weight gain than milk or milk-based meal replacements, both of which are nutrient-rich?