n4 nutrition

Is fructose really that bad? By Emily Greenfield

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Allergies & Intolerances , Kids and Parenting, Diabetes, Diets, General Nutrition, Heart, Cardiovascular & Blood Health, Weight - Body Shape and Composition, Healthy Eating
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There are some who believe that the obesity epidemic and other chronic diseases can be attributed solely to the consumption of fructose.

Fructose is the main carbohydrate found in fruit and can also be found in vegetables and honey. It is a component of sucrose (or sugar), which is made from 50% glucose and 50% fructose. Fructose can therefore be found in any food which contains sugar.

Among the fructose finger pointers is David Gillespie who has been making waves in the nutrition and dietetics world with his book, Sweet Poison. David Gillespie (a lawyer, not a scientist) argues that not only does the consumption of fructose cause us to put on weight, it also leads to heart disease, type 2 diabetes and some cancers. 

However, new high quality research suggests that fructose cannot be blamed for the current obesity epidemic, heart disease or rising levels of type 2 diabetes.

Researchers in Canada have looked into whether the fructose molecule itself can cause weight gain. They researched all of the past studies which compared the effect of fructose and non fructose carbohydrate on body weight. They found that when fructose was substituted for other carbohydrates, it did not appear to cause any weight gain. The researchers also looked at studies where a normal diet and a diet with added calories in the form of pure fructose were compared. Those who ate the diet with added fructose did put on weight. However, this may be due to consuming extra calories, not necessarily to the fructose itself.  Overall, the researchers concluded that fructose is not the sole cause of obesity, it could just be that we eat too many calories from any food source.

Other recent research on fructose supports these conclusions. One study found that when it came to weight loss, a low fructose diet was far inferior to a normal natural fructose diet that we might eat in Australia. Individuals eating either diet lost weight but those eating a normal natural fructose diet lost 50% more!

So what of the other claims that fructose is responsible for heart disease and type 2 diabetes?

Well, there has been some high quality research undertaken recently to address the concerns that the consumption of fructose raises blood pressure. Raised blood pressure is a risk factor for heart disease. Overall, researchers observed a decrease blood pressure in people that had eaten fructose over a long period of time.

Furthermore, the results of another smaller study suggest that small doses of fructose in the diet actually lower blood sugar levels in humans in response to a high glycaemic index (GI) meal like white rice or bread. Lower blood sugar levels are desirable after eating a meal, particularly in those with type 2 diabetes.

So it would appear that fructose is not the bad guy it’s made out to be. It might be easy to point the finger at one nutrient as the culprit for the current obesity epidemic but its often misleading. To reduce the risk of obesity and chronic disease, we need to follow the Dietary Guidelines for Australian adults and focus on a balanced diet of healthy foods and physical activity most days of the week.

Unfortunately, books like Sweet Poison are not a reliable source of nutrition information and only serve to confuse the public about what they should and shouldn’t eat. The dubious claims and errors in David Gillespie’s book have been identified in an open letter by Nutrition Australia (http://www.nutritionaustralia.org/national/media-releases/response-david-gillespie-behalf-nut-net).


Author:  Emily Greenfield


Further reading

Fructose | Nutrition Australia. 2012. Fructose | Nutrition Australia. [ONLINE] Available at: http://www.nutritionaustralia.org/national/frequently-asked-questions/fructose. [Accessed 20 March 2012].

Response to David Gillespie on behalf of Nut-Net | Nutrition Australia. 2012.Response to David Gillespie on behalf of Nut-Net | Nutrition Australia. [ONLINE] Available at: http://www.nutritionaustralia.org/national/media-releases/response-david-gillespie-behalf-nut-net. [Accessed 20 March 2012]. 

Effect of Fructose on Body Weight in Controlled Feeding Trials . 2012. Effect of Fructose on Body Weight in Controlled Feeding Trials . [ONLINE] Available at:http://www.annals.org/content/156/4/291.abstract. [Accessed 20 March 2012].

The effect of two energy-restricted diets, a low-... [Metabolism. 2011] - PubMed - NCBI. 2012. The effect of two energy-restricted diets, a low-... [Metabolism. 2011] - PubMed - NCBI. [ONLINE] Available at:http://www.ncbi.nlm.nih.gov/pubmed/21621801. [Accessed 20 March 2012].

Effect of Fructose on Blood Pressure. 2012. Effect of Fructose on Blood Pressure . [ONLINE] Available at:http://hyper.ahajournals.org/content/early/2012/02/13/HYPERTENSIONAHA.111.182311. [Accessed 20 March 2012]. 

'Catalytic' doses of fructose may benefit glycaemi... [Br J Nutr. 2012] - PubMed - NCBI. 2012. 'Catalytic' doses of fructose may benefit glycaemi... [Br J Nutr. 2012] - PubMed - NCBI. [ONLINE] Available at:http://www.ncbi.nlm.nih.gov/pubmed/22354959?dopt=Abstract. [Accessed 20 March 2012].   

Is fructose really that bad? By Emily Greenfield