Tackling the obesity epidemic--is nutrition the missing ingredient? (Editorial).

In the past few months, childhood obesity has received a great deal of attention. Most recently, the New South Wales and Victorian Health Ministers have announced obesity 'summits' in an effort to identify strategies to tackle the issue. This attention is warranted--overweight and obesity do pose a major public health problem (1). They are associated with increased health risks, they impact on our health care system, large proportions of children and adults are overweight or obese, and the numbers of Australians affected has increased alarmingly in the past ten to 15 years (2). As someone who has struggled to get obesity onto the national agenda I am pleased that obesity is receiving the attention of our health officials. However, as nutrition professionals we do need to ask ourselves whether obesity is getting the right kind of attention, and specifically where nutrition is positioned in the current discussions regarding obesity and its prevention. We also need to consider whether other important nutrition i ssues are potentially being overlooked because of the current focus on obesity?

Is nutrition an important factor in the obesity epidemic? I have attended several national conferences where it has been argued that it is not! The argument goes something like this--during the past few decades while the prevalence of overweight and obesity have increased, the overall quality of the Australian diet has improved and thus the obesity epidemic must be a consequence of decreasing levels of physical activity. There are several problems with this argument. Firstly, it is based on mainly ecological-level evidence of the kind presented by Prentice and Jebb in their seminal paper on 'Gluttony or Sloth' (3), and these data, along with the fact there are only poor physical activity trend data available for Australia, is unconvincing. Secondly, the argument ignores the difficulty in comparing fat intakes over time using self-report data (i.e. that overweight people tend to underreport fat intakes and an increasing proportion of the population are overweight). Finally, the argument is at odds with researc h in the United States where there is evidence to support both the case for increased energy intake and the case for decreased energy expenditure as causing the obesity epidemic (4).

While it may be obvious to nutritionists that changes to our eating patterns are centrally important in relation to the current epidemic of obesity, it is disturbing that much of the discussion regarding how to tackle it focuses almost exclusively on what can be done to increase physical activity. In attempting to come up with a recipe as to how best to address the problem of obesity, nutrition appears to be the missing ingredient. As nutritionists we need to work much harder to convince health officials of the importance of nutritional factors in the aetiology of obesity, and of the potential of nutrition interventions to impact on the epidemic. At the same time, it will be important to remind them that obesity is not the only nutritional issue that deserves attention. Why should we just focus on childhood obesity when among young children, for example, there is good reason to be concerned about fibre intakes and the prevalence of constipation (5), among teenagers calcium intakes and bone development are of concern (6), and when fruit and vegetable intakes of children are sub-optimal (7)?

There is no doubt that obesity is a major public health issue and that action is required. However, it is but one of a range of nutritional problems that are widespread within the Australian community that like obesity deserve attention. Is this possible? I would argue that it is, if we look at the causes of nutrition-related conditions and focus on those, rather than on the diseases or health conditions per se. We need to examine Australian lifestyles and evaluate what is driving the changes in our eating patterns and physical activity habits. Obesity provides us a good opportunity for those of us with an interest in nutrition and physical activity to work together. It is only by doing so that we can develop strategies that will improve population health, and effectively tackle the obesity epidemic.

David Crawford 

Physical Activity and Nutrition Research Unit Deakin University, Burwood

References

(1.) National Health and Medical Research Council. Acting on Australia's Weight: A strategy for the prevention of overweight and obesity. Canberra: Australian Government Publishing Service; 1997.

(2.) Magarey AM, Daniels LA, Boulton TJ. Prevalence of overweight and obesity in Australian children and adolescents: reassessment of 1985 and 1995 data against new standard international definitions. The Medical Journal of Australia 2001;174:561-4.

(3.) Prentice AM, Jebb SA. Obesity in Britain: gluttony or sloth? BMJ 1995;311:437-9.

(4.) Schmitz MKH, Jeffery RW. Public health interventions for the prevention and treatment of obesity. Med Chin North Am 2000;84:491-512.

(5.) Department of Human Services. Filling the Gap: A nutrition needs assessment of children aged 0 to 8 years in Melbourne's Western Metropolitan Region. Victoria: Victorian Government Department of Human Services; 1997.

(6.) McLennan W, Podger A. National Nutrition Survey. Food Eaten. Australia 1995. Canberra: Australian Bureau of Statistics, 1999. (Catalogue No 4804.0.).

(7.) Magarey A, Daniels LA, Smith A. Fruit and vegetable intakes of Australians aged 2-18 years: an evaluation of the 1995 National Nutrition Survey data. Aust N Z J Public Health 2001;25:l550-61.