The Australian Paradox

Professor Jennie Brand-Miller and Dr Alan Barclay

Quit sugar, really?

In many parts of the world, including Australia, around half of the total carbohydrate consumed each day is from sugars, and the other half is from starches and maltodextrins. Core foods that contain natural sugars include fruits, milk and yoghurt, which are important sources of essential vitamins and minerals. For many people in these nations, added refined sugars are a source of unwanted kilojoules and they contribute to tooth decay if consumed frequently in large amounts. However, so are added refined starches and maltodextrins. On average, added refined starches and maltodextrins provide more kilojoules (17.5 kJ / g) than sugars (16.0 kJ / g) and have a higher glycemic index. Enigmatically, these facts are rarely mentioned in popular books, on-line or in the media. One reason may be that unlike sugars, starches and maltodextrins are not listed in foods nutrition information panels – they are the truly hidden nutrients/ingredients in our food supply.

The sugar fructose has received unprecedented attention in recent years; with claims as extreme as that it is as toxic as alcohol. However, there is level 1 evidence (systematic reviews of randomised controlled trials in humans) that when consumed in realistic (non-pharmacological) amounts, fructose is no more fattening, or likely to have adverse effects on common risk factors (blood glucose, blood pressure, uric acid, etc…), than other forms of carbohydrate. We should not be surprised - fructose provides 15.6 kJ / g, has a low GI (19), is sickly sweet (1.7 times more than sucrose, or table sugar), and causes osmotic diarrhoea when consumed in large amounts by itself, limiting the amount that humans can consume under normal (real life) conditions.

Some popular book authors in Australia recommend complete avoidance of fructose – some to the extreme of avoiding certain fruits. Ironically, they do not recommend the complete avoidance of all sugars – despite their exhortations on TV, websites and in books. In fact, they are recommending that people replace all things fructose with other added refined sugars like glucose/dextrose (which are actually the same thing) and rice syrup (which is 45% maltose (another sugar), 3% glucose, and 52% maltotriose (a maltodextrin consisting of three glucose molecules joined together)). All these alternatives provide more kilojoules than fructose, still contribute to tooth decay, and have a much higher glycemic index (100 for glucose/dextrose, 105 for maltose, and 98 for rice syrup based on its constituents). These alternative sugars are not more healthful than the fructose that they are replacing, and when following these diets people are not actually “quitting sugar”. Simplistic advice like “quit sugar” may inadvertently increase the intake of refined starches and maltodextrins, high glycemic index carbohydrates, energy, saturated fat and salt, which could in fact have adverse health consequences.

With respect to carbohydrate-containing foods, rather than attempt to "quit sugar", people should eat at least 2 serves of fruit per day, 2-4 serves of dairy (e.g., milk and yoghurt) per day, and consume a moderate amount (no more than 10% of total kilojoules, or less than 13 teaspoons for an average Australian adult) of added sugars each day. Starches and maltodextrins should not be ignored just because they are not listed in a foods nutrition information panel. It is just as important to consume a moderate amount of added (refined) starch and/or maltodextrins as it is to consume a moderate amount of added (refined) sugars - when purchasing starchy foods look for wholegrain varieties, preferably with a low GI.