On a recent visit to our local greengrocer, I noticed a sign above a small box offering free fruit to children. I asked the shop assistant about the offer and she told me the children visiting the shop with their parents were not very interested in the free fruit. I was not surprised. Given a choice between fresh fruit and chocolate, ice cream or sweets, I have no doubt what most children, or even most adults, would choose. So, what it is about sweets? Why do we crave sugar so much?
The word “sugar” is normally associated with sucrose, a naturally occurring carbohydrate found in large amounts in sugar cane and sugar beet. Almost all the worlds sugar comes from these two plants: ~70 % from sugar cane and ~30 % from sugar beet. While there are many different carbohydrates, what we commonly call sugar is made up of two components – glucose and fructose, which joined together, form sucrose. Sucrose, fructose and glucose are found in many fruits. For example, bananas and apples, two of the most popular fruits, contain around 12% and 10% respectively of these mixed sugars. Lactose is another sugar, made up of glucose and galactose and is found in breast milk and cow’s milk (1, 2). This is the sugar people are talking about when they are “Lactose intolerant”.
All of these “sugars” are used as nutrients by the body. Glucose is particularly important, as it is the energy currency of living things and an important fuel for many of our body processes. Without it, we wouldn’t survive.
Because our bodies know how important sugar is for energy, we are hard wired to eat them. In fact, some people find them irresistible. Why? Because they taste sweet. When we eat sugars they bind to special proteins called “receptors” in our mouth. The receptors give the sensation of sweetness, which, for most people, is highly desirable and hard to resist. There have been many studies in both animals and humans to try to find out how this works. It appears the binding of sugar to its receptors triggers pleasurable effects in the brain, which may explain why we find it hard to resist sweet foods (3). Substances other than sugar can also induce the sensation of sweetness. Indeed, many of the well-known ones like aspartame and saccharin are used as artificial sweeteners to substitute for sugar in some processed foods and drinks, particularly “diet” drinks.
Honey is around 80 % sugar, while fresh fruit contains around 8 – 15% sugar. Dried fruit has a lot more for obvious reasons. However, most of the other fresh food we eat contains little sugar. Cow’s milk has about 4% sugar while there is little sugar in fresh meat. Most vegetables contain at most a few percent, while nuts and legumes may contain up to 5% (2). Processed foods on the other hand are loaded with sugar. Nutritionists call this added sugar “non milk extrinsic sugars” (NMES). Examples of the sugar content of some common processed foods are:
• Breakfast cereals (up to 20% or more)
• Soft drinks (up to 10%)
• Sweetened milk drinks and yoghurt (up to 10%)
• Cakes (up to 30%)
• Biscuits (up to 25%)
• Sweetened yoghurts (up to 20%)
• Ice cream (up to 22%)
Even though pork itself has virtually no sugar, processed pork such as ham and bacon contains significant amounts of sugar (up to 3%) – even more if they have been honey or sugar cured. Considering most people add sugar to their tea or coffee, it doesn’t take a degree in mathematics to work out someone eating a lot of processed food may consume 150 grams (5.3 ounces) of sugar a day or more! Surveys of food intake in children and adolescents have confirmed this estimate and shown perhaps as much as a fifth of all calories consumed are derived from sugars added to processed foods. Fortunately, more recent studies suggest this may be an overestimate (5).
Now what does this mean in terms of how much sugar is being consumed? If the average energy intake per day for 12 – 17 year old boys is around 2,000 calories (4) and every gram of sugar produces about 4 calories of energy (actually 4.18), a fifth of the daily energy requirement is about 400 calories or nearly 100 grams (3.5 ounces) of sugar per day. A liter (quart) of some carbonated soft drinks contains nearly that alone! And as these figures are averages, it is likely some boys would consume even more. This works out to be almost a small teacup full of sugar – each and every day! So if the song in the film “Mary Poppins” says a spoonful of sugar helps the medicine go down, it seems many of us need a teacupful of sugar to help our food go down!
The manufacturers and retailers of processed foods are well aware of our craving for sugar and the “sugar rush” it creates in many people. It’s precisely why they add sugar to so many of their products. How much soft drink or ice cream would you buy if all sugar or artificial sweeteners were removed? There is little doubt most consumers have become accustomed to the taste of the sugar in the foods they buy. Indeed our craving for sugar probably started for most of us with the soft drinks, chocolates, cakes and sweets of childhood. And by the time we became adults we were hooked. This will be obvious to anyone who has gone on a weight loss diet and tried to reduce their sugar intake. Any addiction is hard to break and it is difficult for us to adhere to a low sugar diet.
So what if our children consume so much added sugar? Does it really matter? Well more and more research is showing it matters a lot. The Western world is seeing an epidemic of obesity, particularly in children. In the US the total economic cost of obesity is estimated at US$99 billion per year. In Australia, around two-thirds of adult men and over half the adult women are overweight or obese, adding over $1.2 billion per year to our bill. There is considerable evidence to show you get fat by eating sugar and especially the sugars in processed foods. We know a high calorie intake; excess sugar consumption and spending hours in front of a computer or video game can lead to obesity. More and more research is showing obesity is a significant health risk for a number of degenerative diseases, in some cases greater than smoking (6 – 9):
• Certain cancers
• Emotional and psychological problems
• Heart disease
• Reduced lifespan
• Tooth decay
We know a high calorie intake; excess sugar consumption and a sedentary lifestyle can lead to obesity. This in turn is thought to increase the risk of various degenerative diseases such as cancer, heart disease and diabetes (6 – 8). There is also good evidence excess sugar consumption, particularly through sweetened drinks, can contribute to tooth decay (dental caries) (9).
There are also concerns the calorie rich processed foods we eat are nutritionally poor. Much of the energy in processed foods comes from the added sugar, which has limited nutrient value. A diet high in processed foods may result in nutrient deficiencies for trace elements and unstable vitamins and phytonutrients. After all, if you are getting your energy from a calorie-rich and nutrient poor carbonated soft drink containing loads of added sugar for example, you may not be eating enough of the nutrient rich foods to compensate and give you your daily requirements. Finally, all added sugars classified as NMES are not the same. Some, like fructose, which is being added as high fructose syrups to all manner of foods as a cheaper alternative to sucrose, may cause gastrointestinal distress, particularly if ingested in large amounts (10).
Promoting Good Health believes there is no substitute for fresh food. If consumers do purchase processed food, they need to be aware of what has been added to it. Reading the labels will give you clues. Salt and sugar are often added to processed foods in amounts much greater than those in fresh food. In view of the concerns about the possible health effects of excess salt and sugar, it is best to choose foods low in added salt and sugar whenever possible. In addition to salt and sugar, processed foods also contain a wide variety of other additives like artificial sweeteners, colors, preservatives, emulsifying agents, antioxidants and flavor enhancers to name but a few. And there are also concerns about the possible health effects of many of these additives. So you need to be careful.
We have repeatedly expressed our concerns over the potential health effects of the chemicals used to produce our food and the additives used to process them. You can find more on these topic in other blogs on this website and in the publications in the growing Promoting Good Health series, available through the online store.
Meanwhile stay healthy and happy!
(1) http://www.nal.usda.gov 
(2) Garrow, J.S. et al; Human Nutrition and Dietetics. 4th Edition. Published by Churchill Livingstone, 2000.
(3) McCaughey, S.A.; The taste of sugars. Neurosci. Biobehav. Rev. 32 (5), 1024-1043, 2008.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/18499254 
Full article available online at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2447812/pdf/nihms56303.pdf 
(4) http://www.food.gov.uk/multimedia/pdfs/sugarintakescot2008rep.pdf 
(5) Welsh, J.A. et al; Consumption of added sugars is decreasing in the United States. Am. J. Clin. Nutr. July 13, 2011. E-Pub ahead of print
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/21753067 
(6) Chen, L. et al; Reducing consumption of sugar-sweetened beverages is associated with reduced blood pressure: a prospective study among United States adults. Circulation, 121 (22), 2398-2406, 2010.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/20497980 
Full article available online at: http://circ.ahajournals.org/content/121/22/2398.full.pdf 
(7) Welsh, J.A. et al; Consumption of added sugars and indicators of cardiovascular disease risk among US adolescents. Circulation 123 (3), 249-257, 2011.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/21220734 
(8) Malik, V.S. et al; Sugar-sweetened beverages and risk of metabolic syndrome and type 2 diabetes: a meta-analysis. Diabetes Care, 33 (11), 2477-2483, 2010.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/20693348 
Full article available online at: http://care.diabetesjournals.org/content/33/11/2477.full.pdf 
(9) Lee, J.G. and Brearley Messer, L.J.; Contemporary fluid intake and dental caries in Australian children. Aust. Dent. J., 56 (2), 122-131, 2011.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/21623802 
(10) Beyer, P.L. et al (2005) Fructose intake at current levels in the United States may cause gastrointestinal distress in normal adults. Am. Diet Assoc., 105 (10), 1559-1066, 2005.
Abstract available online at: http://www.ncbi.nlm.nih.gov/pubmed/16183355