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Sugar, Obesity and Kids

11 min read
27 Dec 2015

Sugar has been in the press recently for controversial reasons. It’s being blamed for a raft of health issues, including the upward trend in obesity rates and diabetes. According to the 2012 study ‘Diabetes: the Silent Pandemic: and its impact on Australia’ if rates of diabetes diagnosis remain at their current levels, 3 million Australians over the age of 25 will suffer from diabetes by 2025.

The financial impacts of both increasing obesity and diabetes rates are enormous; obesity and related illness are costing Australians up to $38 billion dollars a year (diabetes alone costs us around $6.5 billion per year). There’s an additional economic toll as well, with data suggesting that obesity-related absenteeism, presenteeism (working through illness and disease that affects productivity) and premature death cause a loss of productivity in the workplace worth nearly $7 billion dollars.

Over 63% of the Australian adult population is considered medically overweight and, according to recent findings from the University of Sydney, obesity now affects more than 25% of the nation’s children. And we have one of the fastest climbing obesity rates in the world. Some of the most prevalent conversations around this phenomenon centre on sugar intake. On average, Australian’s consume nearly 42kgs of sugar per person, per year. The World Health Organisation has acknowledged the alarming impacts of high sugar consumption on health, recommending people reduce their daily sugar intake to 10% of their total energy intake per day.

It’s important to note that the reference to obesity is purely a medical definition, not a value judgement on individual bodies; nor does it refer to an individual’s ability to fully participate in our society. We recognise that discussions around body type are often laden with shaming language, to little or no effect on health. Issues of self-consciousness are particularly damaging to children. Subsequently, a huge weight loss industry operates on the promise of quick-fixes, and rarely involves properly qualified public health professionals, psychologists or even qualified dietitians. We discuss the role of sugar here purely from a scientific and biological perspective, and how it is affecting the health of Australian children.

The science of sugar

Simple sugars are the most basic molecular form of carbohydrates, and provide the most readily available source of the body’s energy requirements in the form of glucose. Other types of sugar molecules include fructose and galactose. It is also available in the form of complex carbohydrates, such as breads, legumes and pasta, but these take slightly longer to break down and provide the glucose component. Complex carbohydrates are often accompanied by dietary fibre, which aids the intestinal tract in its normal processes.

Glucose is converted to energy within our cells and allows our bodies to carry out essential functions. When glucose cannot enter the cells because it is either not available, or severe diabetes is preventing it from entering, an altered bodily state known as hypoglycaemia, which is usually associated with insulin-dependent diabetics, can be a result. This is a dangerous condition because the brain, unlike other bodily cells, can only operate on glucose. In summary: without glucose, we will lapse into a coma and ultimately die.

Fast fact: a process known as gluconeogenesis can use the body’s fat stores to perform a complicated chemical transformation of ketones to a form of glucose, but ketones have their own dangers. The good news is, they will prevent otherwise healthy people from entering into hypoglycaemia.

Added sugar vs. natural sugar

Let’s define natural and added before we move along. Not all sugar is created equal and it’s around this area that the facts can get a little bit confusing. Table sugar is made of sucrose, which is a molecular combination of glucose and fructose. It is typically used to describe “added sugar”. While all sugars are natural, we often hear that term in respect to fruits, vegetables, dairy products and non-processed complex carbohydrates. Other types of sugar, as we have discussed, include lactose, maltose, and galactose. While you may wish to look into the metabolic effects of these types of sugars, the report we are about to discuss, widely covered in the media, looks specifically at fructose.

What happens when we reduce our children’s sugar intake?

Sugar is extremely high in calories, and a high caloric intake no doubt affects our health, but is it the major culprit? The study authored by paediatric endocrinologist Dr Robert Lustig argues that sugars containing fructose pose a threat to us all, and specifically studied a cohort of children to examine the effects. It examined the effects of restricting sugar intake in obese children to see if it resulted in improved metabolic function.

The aim of this study was not to reduce weight but to see if restricting fructose intake, without reducing caloric intake, had any effect on improving obese children’s metabolisms. Metabolism describes all chemical processes that take place in the body, but usually refers to measurable indicators of disease, such as insulin and glucose levels, cholesterol and triglycerides. Dietary sugars in the form of fructose were reduced from 28% to 10% (in line with the new WHO guidelines) and those calories were replaced with starches to ensure stable weights were maintained for the length of the study, which was 9 days.The study results are compelling – concluding that isocaloric fructose restriction (reducing sugar intake whilst keeping calorie intake the same) improved metabolic indicators in the children studied. The study indicated improvement in glucose tolerance and hyperinsulinemia, diastolic blood pressure and LDL-cholesterol levels. These effects were measured after nine days of reduced fructose intake. The study sent health reporters into a frenzy, with article upon article sharing the report’s conclusions.

More about this study

The study looked at 43 participants aged between 8 – 18 years old who had been diagnosed with obesity and at least one other ‘co-morbidity’ factor (additional symptom, like hypertension, impaired fasting glucose or hyperinsulinemia). Each of these children had required medical attention related to obesity. This study excluded children diagnosed with diabetes, were pregnant or were taking any neuroactive medications. Participants were interviewed by a dietitian to ascertain their average daily caloric intake and to establish baseline macronutrient profiles (e.g. how much of each type of food, fat or sugar they consumed daily).


Not all media outlets reported on the study uncritically, and other academics have maintained scepticism. For example, The Guardian discussed the nuances of the study design and the methodology by referring to a number of relevantly qualified academics, as did Scientific American and the Science Media Centre. Specific criticisms include the fact that the number of children involved in the study was small enough to be considered preliminary, that the study was not statistically well-controlled (meaning the way the data was collected and interpreted may have been flawed), and it did not have a control group. A control group – a relevantly equal group that does not experience the variable being studied – is used to examine results against the experimental group in order to control for other variables. It is the gold standard in this type of study. It has also been pointed out that the baseline intake of the participants (prior to the start of the study) was self-reported, a factor that can be exaggerated or grossly underestimated., a non-profit group that analyses statistics from a range of studies and sources, critically examined the raw data. Firstly, they note that food surveys, when self-reported, are notoriously unreliable. They chime in with the discussion on the lack of a control group, meaning any other variables at play are unable to be identified. A variable is a contributing factor to a specific outcome. In this case, we cannot definitively conclude that there were no other variables at play. These variables may be behavioural or biological. The response also finds that the number of calories calculated to maintain the children’s weight was grossly underestimated. Other, more complex, analysis can be found within the article.

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What we can conclude about the sugar study

Without further studies and a closer look at the biological functions of fructose, it’s difficult to conclude anything beyond the fact that this is an interesting area of ongoing research. What is rarely disputed by relevant experts, however, is the need to cut down on our sugars as a part of a balanced diet. This is particularly true for hidden sugar in the form of sucrose, which is added to all kinds of processed foods, despite health claims that sidestep the labelling laws. Soft drinks in particular are raising our caloric intake without providing any nutritional benefit beyond meeting our energy requirements. The problem is that we too readily exceed them. These studies discuss the link between obesity and sugar intake, but none should be considered in isolation. Studies should be rigorously reviewed and replicated by other researchers.

Where is sugar hiding?

With this information in mind, it makes sense to at least consider reducing your sugar intake and that of your children. The health and behavior of your children today can have a dramatic impact on their lives. While you may not feel like you have a diet high in sugar, it’s still worthwhile looking at where it may be hiding in plain sight. provided some well-needed inspiration for this list.

  • You’re drinking more sugar than you think. Even if you don’t drink ‘sugary drinks’ like soft drink, energy drinks or flavoured milk, you may be consuming more sugars in your daily juice than you realise. Some children’s fruit drinks contain up to 7 teaspoons of sugar per serve, the same as cola drinks. And you may think that having a fruit smoothie is a healthy alternative to mid-morning snack but you may be better off with that chocolate bar. The popular Boost Juice Berry Crush smoothie has 65g of sugar – compare that to 31g of sugar in a 60g Kit Kat bar.
  • Sauces and salad dressings. Surprisingly, sauces like tomato sauce and BBQ sauce can pack a sugary punch. There can be up to 13 grams of sugar in just two tablespoons of BBQ sauce. Salad dressings often also contain sugar. Consider a simple homemade dressing with an olive oil base.
  • Fruit yoghurt. Yes, there’s naturally occurring sugar in dairy products and in fruit but most ‘fruit yoghurt’ also contains added sugar, so consider swapping it out for natural Greek yoghurt and adding your own fruit.
  • Pasta sauce. Pre-made pasta sauce can have up to 24 grams of sugar in every cup, so make your own from scratch if you want to avoid the extra sugar.
  • Sugar ‘alternatives’. Just because you find agave syrup in the health food section of the supermarket doesn’t actually mean that it’s ‘healthy’. Agave is 85% fructose.
  • Dried fruit. But it’s fruit?! Not all of it. Read the packaging carefully – often added sugar is the second ingredient on the label. Just a 1/3 cup serving of dried fruit might contain 24 grams of sugar.
  • Granola bars. They’ve got whole oats and dried fruit, so they must be healthy… except for the 12 grams of added sugar packed into each little bar. Now, not all granola bars are equal, so if you love a granola-based afternoon pick me up, make sure you compare the nutritional information to find one with low sugar content.

Your favourite foods – reimagined

If it seems like sugar is everywhere, but it’s easy to find simple ways to substitute excess sugar for better alternatives for your kids.

  1. At breakfast, swap your cereal for rolled oats; most pre-packaged breakfast cereals are full of added sugars. Add a modest teaspoon of honey to sweeten the deal (though remember that honey is 100% sugar!). Swap your white toast for whole-grain to improve your nutritional intake.
  • At lunch, avoid those extra sauces in your children’s sandwich or roll, stick to whole grain bread, prepare a salad with a dash of olive oil and balsamic vinegar instead of pre-made dressing, swap out mayo for mustard (mayo is high in sugar and saturated fats) offer water or sugar-free cordial instead of a soft drink or flavoured milk drinks.
  1. Snacks are fine, but don’t reach for the block of chocolate. Have a piece of fruit or a handful of nuts on hand instead. Swap that afternoon muesli bar for a few veggies and hummus.
  1. Juicing often removes fibre while holding onto the sugars. Skipping the juice and going for the whole fruit will mean your kids consume less fruit overall and therefore less sugar. Some fruits are naturally lower in sugar than others, and strawberries are a great example of this. It’s worth noting that fruit should be a part of a balanced, healthy diet, and shouldn’t be negated entirely. We talk more about this below.

Knowledge is power

The most important thing to remember is that sugar isn’t intrinsically the enemy; like anything, sugars have a place in a balanced diet but it’s important to recognise where extra sugar may be sneaking into our everyday diets. By being aware of where and how we consume added sugars, we can make healthier substitutions and swaps to benefit our health and the health of our children.

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