Lisbon ConferenceStemming the global obesity epidemic: What can we learn from data about social and economic trends?☆
Introduction
Researchers are recognizing increasingly that changes in dietary and physical activity patterns are driven by changes in the environment and by the incentives that people face.1, 2 The policy debate moves more slowly and continues to emphasize individual choice. For example, the Charter of the European Union Platform on Diet, Physical Activity and Health begins with: ‘European Union citizens are moving too little and consuming too much: too much energy, too many calories, too much fat and sugar, and salt.’3 Many factors have been suggested as causes of the ‘obesity epidemic’, including snack food, cars, television, fast food, computer use, vending machines, suburban housing developments, portion sizes and female participation in the labour force. Putting a multitude of isolated data points into a coherent picture is a challenging, but necessary, task to assess whether proposed solutions are promising or likely to lead down a blind alley. Conventional wisdom is a very unreliable guide to guide policy.
Can one identify important and less important behavioural changes over past decades and relate them to changes in environmental incentives? People face trade-offs in allocating their scarce resources of time and money to best achieve their goals, including health. Studying what people are doing with their time and money is a good start towards understanding how economic incentives have altered energy intake and energy expenditure in a way that has led to weight gain.
Interventions to change diets or physical activity by altering economic or environmental incentives affect many dimensions of our lives. Economic analyses can quantify the trade-offs involved and assess how different stakeholders are affected. This information can improve the effectiveness, sustainability and political feasibility of proposed interventions. It is probably no exaggeration to say that the key issue in the world of political decisions is the distribution of costs and benefits; an issue at the centre of economics. As the focus of interventions to prevent obesity shifts away from traditional informational/educational to environmental and policy approaches, complementing a public health perspective with an economic perspective becomes increasingly important.
A recurring theme in this article is that both economic and public health perspectives play an important role in the policy process, and that interventions supported by both perspectives are most likely to be effective and politically acceptable. However, there is a wide gulf between these two research perspectives, and they often appear at odds with each other. Harnessing any synergy requires an understanding of both perspectives.
Section snippets
Trends versus cross-sectional differences in obesity
In spite of increased recognition and media attention to the problem, the obesity epidemic continues to worsen. Just between 2000 and 2005, the prevalence of obesity in the USA increased by 24%, while the number of severely obese [body mass index (BMI) >40] cases increased by 50%, highlighting the importance of change over time.4 When looking at trend data, changes in BMI appear to be very similar across all population groups, although the prevalence at any point is highest among groups with
Time and money: Where did they go?
Many factors have been suggested as causes of the ‘obesity epidemic’ and, by implication, as key targets for obesity prevention interventions. While there is no shortage of point-in-time numbers, comparable data across several years, let along several decades, are rare. This section summarizes what the author has found to date10, 11, 12 plus a few updates. There are several relevant insights, although more surprising is how little is known about societal changes affecting weight gain, even
Summary
A decade ago, a study published in the British Medical Journal entitled ‘Obesity in the UK: gluttony or sloth?’ energized the debate whether the obesity epidemic is caused by declining physical activity or increased energy intake.21 In that case, the authors came down on the ‘sloth’ side for adults in the UK. Even if one could meaningfully separate energy intake and expenditure, the data are too limited to support a conclusive analysis because the energy imbalances responsible for the secular
References (22)
Increases in morbid obesity in the USA: 2000–2005
Public Health
(2007)The economics of physical activity: societal trends and rationales for interventions
Am J Prev Med
(2004)- et al.
Suburban sprawl and physical and mental health
Public Health
(2004) - et al.
Obesity and the environment: Where do we go from here?
Science
(2003) Preventing childhood obesity: health in the balance
(2004)- European Union. Platform on diet, physical activity, and health. Charter, 2005. Available at:...
- et al.
Prevalence of overweight and obesity in the United States, 1999–2004
J Am Med Assoc
(2006) - et al.
Weight gain trends across sociodemographic groups in the United States
Am J Public Health
(2005) The World Health Organization MONICA Project (Monitoring Trends and Determinants in Cardiovascular Disease): a major international collaboration
J Clin Epidemiol
(1988)- et al.
Educational level, relative body weight, and changes in their association over 10 years: an international perspective from the WHO MONICA Project
Am J Public Health
(2000)
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This paper is a revised version of the paper presented at the first international conference of the journal Public Health in Lisbon, May 2007.