- Timothy P Gill, principal research fellow1,
- Louise A Baur, professor23,
- Lesley A King, adjunct senior lecturer3
- 1Boden Institute of Obesity, Nutrition and Exercise, University of Sydney, Sydney, Australia
- 2The Children’s Hospital at Westmead, Locked Bag 4001, Westmead NSW 2145, Australia
- 3Sydney School of Public Health, University of Sydney
- Correspondence to: L Baur
Physical inactivity is a major contributor to the global burden of disease, being associated with a range of negative consequences for health, including cardiovascular disease, type 2 diabetes, reduced functional capacity, and poorer mental health.1 Clearly the promotion of both increased physical activity and reduced inactivity must be important elements of any public health programme. However, a strategy that targets physical inactivity but ignores the problem of obesity is unlikely to bring overall improvements in health. We consider that such an approach is flawed.
Diet and health
High population prevalence of physical inactivity is just one marker of a society’s overall obesogenic lifestyle, which comprises a broad set of inappropriate environmental and behavioural patterns. A wide range of evidence from epidemiology, case-control studies, and clinical trials has identified poor quality nutrition (encompassing such elements as an increased intake of energy dense nutrient poor foods and sweetened drinks, low dietary fibre intake, and large portion sizes) as another major contributor to the development of obesity and other health problems such as dental caries, hypertension, and various cancers.2 As a consequence, any approach that overlooks these profound influences of diet on health and risk of chronic disease (including those that are independent of obesity) is likely to be counterproductive.
Overweight and obesity have serious immediate health consequences for both the individual and the broader community,3 4 and these need to be tackled decisively. These health risks accrue from very early in life and, if obesity is persistent, are associated with more severe chronic disease and early death.5 6 On its own, improving physical activity will have little impact on reducing overall levels of already established obesity.7 And, while some of the health consequences of overweight and obesity in adults, such as type 2 diabetes and cardiovascular disease, can be ameliorated by high levels of physical activity, they are not completely removed or reversed.8
For all these reasons, people who are obese need access to high quality treatment services provided by well trained professionals, with the aim of treating both the obesity and the related morbidities. Although the evidence on what is effective in treating obesity is still emerging,9 10 effective management is impeded because services in primary, secondary, and tertiary care are often under-resourced, relatively uncoordinated with other parts of the health system, and have long waiting lists. The almost inevitable result of a reduced focus on obesity is that services do not reach a large proportion of the people who most need them.
Another concern with ignoring overweight to focus solely on physical activity is that it may reinforce the pervasive negative view that obesity cannot be prevented or managed and suggest that promoting physical activity is more successful. However, this is a misreading of the literature. Although previous programmes to prevent or manage obesity at the individual or population level have had limited success in terms of body mass index, recent small group and community based lifestyle programmes seem to be more effective at reducing weight and associated illness.9 10 11 12 Efforts to increase physical activity have also had limited effect. A Cochrane review of health promotion programmes to improve physical activity found that most had only moderate success.13 Such programmes have tended to focus on improving leisure time physical activity or sport, which often make a minor contribution to overall physical activity levels and energy expenditure.14 Indeed, there is some evidence from cross sectional and clinical trial data that people taking part in exercise programmes reduce physical activity at other times of the day or even increase dietary intake.15 16
A focus on reducing obesity through a broad range of actions is likely to be more effective in preventing chronic disease and produce larger population health gains than an approach that solely focuses on inactivity. To achieve these outcomes a broad portfolio of strategies is required. Such initiatives must include efforts to improve physical activity in addition to diet and other behavioural issues, but also require greater attention to the pervasive structural, economic, and social factors that influence our ability to change behaviours favourably.2 17 Programmes should include improved urban planning (for example, cycle lanes, more accessible and affordable public transport, increased access to green space), decreased dependence on motor vehicles, and changes in local food production, national food distribution cost structures, and food pricing strategies.18 A public health agenda that is narrowed to focus on promoting physical activity is unlikely to deliver on all these issues.
Cite this as: BMJ 2010;340:c2602
Competing interests: All authors have completed the unified competing interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare (1) no financial support for the submitted work from anyone other than their employer; (2) no financial relationships with commercial entities that might have an interest in the submitted work; (3) no spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work; (4) no non-financial interests that may be relevant to the submitted work
Provenance and peer review: Commissioned; not externally peer reviewed.