In reply to Blinded by science.

(Nutr Diet 2003;60:150-1)

This leading article took issue with the key message from the Heart Foundation's position statement that a reduction in kilojoule intake, rather than a reduction in fat intake per se, is the major determinant of weight management (1). However, this statement is consistent with the Dietary Guidelines for Australian Adults (2) and the World Health Organization Report 916 (3) which discusses energy balance and energy density as factors in the incidence of overweight and obesity.

The essence of the disagreement is that the statement that dietary fat is not independently related to obesity is a moot point. In fact the article appears to agree that dietary fat exerts its effects through an increased energy intake rather than some other intrinsic effect of fat on energy metabolism. It is likely that the difference of opinion in regard to the policy paper is due to a misunderstanding as to how the document was planned to be used.

The document was never intended to result in a mass media communication stating that fat was no longer important. This is far from the case and the Heart Foundation statement does not imply that fat is unimportant in energy balance.

Perhaps the need and relevance of the policy statement is better appreciated if one observes the direction that the food industry is taking with the development of low fat and fat reduced products. Intuitively such products would be lower in kilojoules, and in the early days with the introduction of low fat dairy products and lean meats and poultry this was certainly the case. However, what we are now seeing is that 'low fat' is not always synonymous with 'low kilojoule'. This has been through the introduction of new energy dense refined carbohydrate products and increasingly larger portion sizes--a consequence of nutrition recommendations being inadequately precise.

Health professionals, especially dietitians, need to be aware of the subtle but important difference between dietary fat having a direct or indirect relationship to obesity. Without appreciating this difference, health professionals may occasionally get the messages wrong, with unintended consequences. What the policy says is that for weight control the true message is 'kilojoules count'. Health professionals need to understand this, the food industry needs to know this and the public needs to be appropriately informed on how to manage their weight.

Heart Foundation position statements are based on critical review of the published scientific literature and are guided by the advice from expert honoraries and scientific advisory committees. All position statements are required to be ratified through the Heart Foundation's internal quality assurance process. Heart Foundation position statements are intended to be used as guides for further developing communication messages to consumers and the food industry.

The Heart Foundation is pleased that our position statement is creating healthy scientific debate and encourages this process in the health arena.

References

(1.) National Heart Foundation of Australia. Position statement on dietary fat and overweight/obesity. Nutr Diet 2003;60:174-6.

(2.) National Health and Medical Research Council. Food for Health: Dietary Guidelines for Australian Adults. Canberra: Commonwealth of Australia; 2003.

(3.) World Health Organization. Report 916: Diet, Nutrition and the Prevention of Chronic Disease. Geneva: WHO; 2003.

Manny Noakes

Chair, Nutrition and Metabolism Advisory Committee

National Heart Foundation of Australia