Are the recent reports true? Are those sweet white crystals really as dangerous and addictive as alcohol or tobacco? HFG dietitian Zoe Wilson tells what you should know about sugar.
Recently, US paediatritian Dr Robert Lustig kicked off a worldwide debate when he published an article describing added sugars as “toxic”. So worried was he by its harmful effects on our health that he called for legalised control of all foods and drinks with added sugar – and more specifically fructose – just like the restrictions on the sale of cigarettes. And so began a media firestorm.
The debate was further inflamed with the release of controversial bestsellers Sweet Poison and Big Fat Lies by Australian lawyer David Gillespie, where he details his research and his own success shedding 40kg by cutting all foods containing fructose from his diet. Gillespie claims his research proves that fructose is “as addictive as nicotine” and calls sugar “very dangerous”.
But just how true are these claims? And what do other leading health experts say about the health risks of sugar?
Public health enemy number one
Those sweet, white crystals you pour into your coffee are just one of several varieties of sugar.
To really understand the debate, it’s important to know the differences (see guide below). Simple table sugar is made up of molecules of glucose joined to fructose. When we eat sugar, these glucose and fructose molecules separate and our bodies then deal with each of them differently.
The sugar critics claim that, at this point, fructose is dealt with like alcohol, which turns straight into fat and is stored around the liver, giving rise to a range of health problems, ranging from obesity to non-alcoholic fatty liver disease and the onset of type 2 diabetes.
However, some leading health professionals believe the scientific evidence doesn’t support such claims. Dr Alan Barclay, chief scientific officer at the Glycaemic Index Foundation and Head of Research for Diabetes Australia, insists these health claims about fructose have little basis in truth, and that the story is not quite as simple as Gillespie and Lustig suggest.
“I think that focusing on a single nutrient alone and scaremongering is exacerbating the [obesity] situation,” he says.
The idea of banning sugar, he believes, is not going to cure the world’s weight woes. Instead, we should be focusing on the foods we should eat – not the ones we should cut out.
“Prohibition doesn’t work. Instead, we need to focus on the positive,” he says.
A case of mistaken identity
All three basic forms of sugar (glucose, fructose and galactose) occur naturally – as well as being added to foods such as lollies, chocolate, or your cappuccino.
Glucose, for example, is part of the starch found in pasta, rice, potato and bread.
While fructose, for all its bad press, is found naturally in fruit, honey, maple syrup, barley, rye and most vegetables including onion, sweet potato and corn.
Dairy products derive their sweet taste from lactose, made up of galactose and glucose.
Despite sugar’s bad reputation, we do actually need some forms to keep our bodies running the way they should.
Our bodies need a supply of glucose, which acts like the petrol in a car, travelling around in our blood and being drawn on for fuel. As such, glucose is our body’s first preference for energy. In fact, glucose is the only form of energy our brain can run on, making it essential that we don’t cut it out entirely from our diets.
What’s alarming about the recent debate is the confusion it has created – namely that all sugar is bad.
A spate of sensational TV current affairs show segments have contributed to cementing this popular misconception. While overlooking the important difference between fructose and sugar in general, the media has gleefully leapt on Lustig’s provocative comments that our rampant consumption of fructose is slowly killing us – including his proclamation that: “Fructose is ethanol (alcohol) without the buzz”.
Addicted to sugar?
Meanwhile, in the scientific world, Lustig’s claim that every molecule of fructose is converted straight to toxic fat is challenged by many scientific studies. They show that fructose is, in fact, converted to a number of different by-products (not only fat) which our body either uses straight away as fuel, or stores to use as fuel when it’s needed.
There’s more to the sugar critics’ claims that also bears investigation. For example, according to Gillespie, “Fructose is not only directly making us fat, but it inhibits our appetite control system, so it also gives us permission to eat more of everything else.”
He claims the hormones which contribute to us feeling full after eating other foods (including glucose) are not released when we eat fructose.
Without these triggers, Gillespie argues, when we eat fructose we feel less satisfied and so we eat more.
Since the advent of processed foods, our fructose intake has increased dramatically. It’s now a common part of our western diet and, according to Gillespie, we’re all ‘hooked’.
But this addiction argument has been challenged by research. A review published in the journal Clinical Nutrition found there was no evidence to support claims that high sugar consumption in humans was related to addiction.
A second paper, published in Nutrition found that while there is some evidence to support Lustig’s views, “the case for fructose being less satiating than glucose... is not compelling.”
According to critics of Gillespie and Lustig, much of the research they base their theories on has been conducted on animals, rather than on humans. In these studies, subjects have had to consume vast amounts of sugar in forms that are not readily available in real life.
“Most studies showing any negative side effects were in rats who ate [fructose] in amounts about six times what a human would consume”, says Dr Barclay.
One of the short-term effects that research has found with eating high doses of fructose is diarrhoea, but as Dr Barclay explains, we would have to eat about 100–250g of pure refined fructose to experience this side effect. “This equates to 200–250g sucrose [more than a cup of table sugar] – and we really don’t consume that in a day”.
Is sugar why we’re getting fatter?
Here’s a curious thing. Despite the claims from Gillespie that we are eating extraordinary amounts of sugar, the last National Nutrition Survey found 95% of Australians’ total sugar consumption was well within the dietary guidelines.
In fact, an Australian study published in the peer-reviewed journal, Nutrients, suggests that while our weight has been increasing, our intake of sugar has been decreasing. It found that between 1980 and 2003 the rate of obesity in Australia had increased three-fold, but in that time our sugar consumption had actually declined. Addressing the sugar-obesity link, the authors concluded, “efforts to reduce sugar intake may reduce consumption, but may not reduce the prevalence of obesity”.
Internationally, a large review of clinical trials in the American Journal of Clinical Nutrition, suggested there is no real evidence that eating fructose in amounts up to 100g every day increases your risk of being overweight, providing it is part of your total food intake, not extra kilojoules. It found that only when study participants added kilojoules to their normal diet by eating more fructose did they gain weight. The authors attributed this to the increase in kilojoules, not the fructose itself. However, there is some evidence that drinking large amounts of sugar, (for example in soft drinks or juice), can contribute to weight gain, as they don’t provide as much satiety as solid foods.
So, what are we to make of the amazing weight loss stories we hear from people who have cut out sugar?
Health experts would argue that their weight loss success is not simply due to cutting out sugar, but eliminating the kinds of unhealthy, high-kilojoule foods that the sugar is in.
Often foods that are high in sugar are also high in fat and refined starches, such as many fast foods, cakes and biscuits. This combination of ingredients creates foods high in kilojoules but low in energy-sustaining nutrients such as protein and fibre, so they don’t keep us full for very long. As a result, we eat more, adding more kilojoules, which leads to weight gain.
How much is too much?
While there are no specific recommendations for fructose intake, there are general guidelines for how much added sugar we should consume. The World Health Organisation recommends less than 10 per cent of our daily kilojoule intake should come from added sugars.
“This equates to 13–14 teaspoons of added sugar per day, which is roughly equivalent to the amount found in one can of soft drink,” says Dr Barclay.
Importantly, this figure doesn’t include foods that naturally contain sugar such as fruit, dairy, grains and vegetables. The reason for this is that these foods also give us many other nutrients, which makes them an important part of a healthy diet.
Rather, it’s those foods and drinks where sugar is added in large quantities that are the problem. Lollies and soft drink, for example, have very high concentrations of sugar. While other foods like doughnuts, pastries and chocolate bars contain lots of sugar along with unhealthy fats. All of these foods should be occasional treats.
“We should focus on real foods, not party foods – fruit, vegies and low-GI whole grains for example – and not focus on what we should be cutting out,” says Dr Barclay.
So the health message is simple: adding a teaspoon of sugar to your tea, or honey to your porridge isn’t harmful. You can enjoy sugar, just be sensible about not overdoing foods with high concentrations of added sugar. And isn’t that what your mum always told you?!
How much sugar are you really eating?
Aim to eat less than 13–14 teaspoons (about 55g) of added sugar per day.
1 cup Nutrigrain has 12.8g sugar = 3.2 teaspoons sugar
1 Uncle Tobys Chewy choc chip chewy muesli bar has 5.7g sugar = 1.4 teaspoons sugar
375ml can of Coke has 39.8g sugar = 10 teaspoons sugar
Five easy ways to reduce your added sugar intake
Swap sugary drinks such as cordial, soft drink, sports drinks and caramel lattes for a reduced-sugar option – try water, tea, a skim latte or 1–2 teaspoons Milo with skim milk.
Satisfy a sugar craving with fruit or reduced-fat yoghurt – this will not only provide you with a sweet hit, but also other crucial nutrients such as fibre, protein, vitamins and minerals.
Reduce the sweet treats you have each day and check the portion size. Chocolate, cake and biscuits all not only have added sugar, but they are also high in total fat, saturated fat and even sodium without many good nutrients, so it’s best to save them for special occasions.
Check your breakfast cereal – aim for one with less than 15g sugar per 100g (or less than 25g if it has fruit) and check the ingredients list for sugar. If it’s in the first 3 ingredients, it’s among the most concentrated ingredients in the pack, so put it back. Original oats, wheat bran cereals and untoasted muesli are all good options.
Make dessert after dinner an occasional treat – after you’ve eaten, have a cup of tea, or even just a big glass of water to signal the end of a meal.
A short and sweet guide to sugar
Sucrose: Simple table sugar is made of half glucose and half fructose. The main sweetener used in processed foods in Australia.
Glucose: The simplest form of sugar and the body’s main fuel. Found in fruit, table sugar and starches such as grains and starchy vegies. Stored in the muscles and liver as glycogen for energy when needed.
Fructose: The simple sugar found naturally in fruit, honey, maple syrup, nearly all vegies (especially onions, potatoes, sweet potatoes and corn) and some grains (wheat, rice, barley and rye). Combines with glucose to form simple table sugar.
Lactose: The natural sugar found in dairy products. Made up of galactose joined to glucose.
Did you know?
Claims such as ‘All natural’ or ‘No added cane sugar’ don’t necessarily mean the product is sugar-free. Concentrated pear and grape juices are often used instead of cane sugar.
The recommended intake for added sugars is about 13-14 teaspoons per day.