Fructose

This answer is brought to you by many of the Australian nutrition professionals who regularly contribute to the Nutritionists Network ('Nut-Net'), a nutrition email discussion group.

A book called Sweet Poison includes the claim that a type of sugar called ‘fructose’

is a poison that is slowly killing us. Is there any truth to this?

In his book Sweet Poison (published in 2008), and in the ABC Radio National program Ockham’s Razor
(broadcast in July 2009), David Gillespie claims that the obesity epidemic as well as many chronic diseases
are entirely attributable to the consumption of fructose.
 
Fructose is the major carbohydrate present in fruit,
and although some dietary fructose is derived from fruit, much fructose consumed in the diet is derived from sucrose (commonly known as ‘sugar’) and from foods containing added sucrose. This is because sucrose consists of 50% fructose and 50% glucose. Sweet foods such as desserts, cakes, chocolate and other confectionery, and sweetened beverages such as carbonated soft drinks, sports drinks and so on, contain large quantities of added fructose. Fruit juice is also high in fructose.
 
In Sweet Poison it is argued that unlike other foods, fructose does not satisfy hunger. When eating fructose-rich foods, people therefore continue to eat even after consuming more than what is required. The author claims that as a result, nearly everyone is putting on weight. Sweet Poison continues to argue that fructose has severe and adverse effects on health, leading to alarming levels of chronic disease including heart disease, type 2 diabetes and even some cancers.
 
Sweet Poison recognises that fructose derived naturally from whole fruit has a different metabolic effect on the body when compared with fructose added to the diet, largely due to the presence of dietary fibre. Gillespie therefore recommends consuming two serves of fruit daily, as outlined by the Australian Dietary Guidelines. Because the fructose in fruit juice is not accompanied by dietary fibre, Sweet Poison suggests that drinking fruit juice results in the same deleterious health outcomes as does consuming added fructose.  
 
To prevent or treat obesity and chronic disease, Gillespie recommends avoiding all sweet-tasting foods (other than two daily servings of fruit). Furthermore, his comment ‘Don’t exercise if your dominant purpose is to lose weight: let a lack of fructose do that instead’ belittles the role of physical activity in the treatment and prevention of overweight.
 
Unfortunately, Sweet Poison is based on gross misinterpretation and neglect of key aspects of the nutrition-related scientific literature. Moreover, the advice contained within is inconsistent with the Dietary Guidelines for Australians published by the National Health and Medical Research Council (NHMRC), and with the NHMRC guidelines for treatment and prevention of obesity which emphasise the importance of physical activity in weight control.
 
In fact, Sweet Poison is replete with errors and dubious claims. Though strong evidence suggest that excessive consumption of sucrose (and therefore fructose) is harmful to health, no evidence supports that claim that added fructose is a poison at any dose. This is recognised in the advice given by all national and international health authorities to limit (not avoid) intake of sugars and sweetened foods. 
 
Many Australians eat excessive quantities of sugar and would benefit from reducing their intake of sweetened foods and drinks. However, total avoidance is unnecessary, and there is no evidence to support Gillespie’s claim that ‘Every day that fructose remains a part of our diet, is a death sentence for thousands of Australians’.
 
Sweet Poison is not a reliable source of information regarding the effects of fructose on body weight and health. To reduce the risk of obesity and to optimise your health, the best advice is to follow the Dietary Guidelines for Australian adults, particularly:
  • Eat plenty of vegetables, legumes and fruits
  • Eat plenty of cereals (including breads, rice, pasta and noodles), preferably wholegrain
  • Limit saturated fat and moderate total fat intake
  • Drink plenty of water
  • Limit your alcohol intake if you choose to drink
  • Consume only moderate amounts of sugars and foods containing added sugars
  • Prevent weight gain: be physically active and eat according to your energy needs
 
Click here to read the Nut-Net open letter to David Gillespie, which identifies some of the errors and dubious claims outlined in his book Sweet Poison.
 
For more information on issues related to healthy eating and weight maintenance, visit our Resources and Fact Sheets page.
 
Please see the attachment below for more detailed information about fructose and health outcomes.
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Fructose_Printable Summary.pdf130.07 KB

 

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