The concerns

Overweight and obesity cause or exacerbate a large number of health problems, both independently and in association with other diseases, and are among the most important contributors to ill health. Unfortunately, many of the health risks associated with increasing body weight begin their manifestation in children and young adults; of great current concern is the increasing prevalence of type 2 diabetes and associated medical complications in young overweight adults. The intra-abdominal visceral deposition of adipose tissue, which is characterised by fat around the waist, is a major contributor to the development of high blood pressure (hypertension), raised blood glucose levels (type 2 diabetes) and abnormal blood fat concentrations (hyperlipidaemia)⁽Reference Kopelman¹⁾. The concept of a combination of these problems in an individual is termed the metabolic syndrome, which refers to the phenomenon of clustering of risk factors for heart disease. It is worrying that overweight and obese youngsters may show the blood changes associated in older life with heart disease and, additionally, have fat deposited in their livers. Furthermore, it can be anticipated that excessive weight carried by young adults will lead to osteoarthritis of the back, knee and hip in the future⁽Reference Kopelman¹⁾. Most of the medical complications will not present to a medical practitioner until 20–30 years have passed; hence, it is difficult to discern immediate benefits to younger generations from modest reductions in body weight. In prevention terms the symptomatic benefit to an individual may be relatively quick but the overall benefit to society will take years⁽Reference McPherson, Marsh and Brown²⁾.

This lag in perceived benefit will have contributed to the lack of success of previous attempts to curb the obesity epidemic.

Foresight

To some individuals being overweight has become a normal condition with an acceptance that the UK is becoming an obese society; this transition has been at least three decades in the making and it will take several decades to reverse the factors that are driving this trend. The UK Government's Foresight programme, in the Government Office for Science, was asked to consider how society might deliver a sustainable response to obesity in the UK over the next 40 years. Foresight works across government departments to analyse complex cross-cutting issues. Its projects entail the rigorous use of science to inform future thinking in Government. The Tackling Obesities: Future Choices project has involved >300 experts and stakeholders, and has extensively reviewed the evidence base and used a variety of horizon-scanning techniques to help identify possible solutions⁽³⁾.

The Foresight project's objectives were to:

1. 1. use the scientific evidence base from across a wide range of disciplines in order to identify the broad range of factors that influence obesity and look beyond the obvious;

2. 2. create an understanding of the relationships between key factors influencing levels of obesity and their relative importance;

3. 3. build on this evidence to identify effective interventions, analyse how future levels of obesity might change and identify the most effective future responses.

The analysis of published evidence, commissioned by Foresight, has revealed that the causes of obesity are embedded in an extremely complex biological system, set within an equally complex societal framework. Furthermore, the scale of the challenge to prevent obesity is substantially increased by the complex nature of the condition. The many causes of obesity argues against depending on a number of unconnected solutions to address the issue, and against a focus on single aspects (on one population group, for example) because this approach is unlikely to bring about the scale of change required.

A long-term comprehensive strategy needs to incorporate a range of policies that act in at least three dimensions:

1. 1. systemic change focusing on initiatives to change behaviours and the cues for such behaviours relating to food, physical activity and physiological and psychosocial factors;

2. 2. interventions designed to change a single factor conducted at many levels of governance, i.e. at individual, local, national and global levels;

3. 3. different interventions targeting the same process of behaviour change applicable across a lifespan.

The obesity epidemic

The Foresight Report was published in October 2007⁽³⁾. It confirms that the appetite control system is less responsive to diminished body energy needs, the consequence of low physical activity; this asymmetry of appetite regulation favours over-consumption because of a strong and rapid response to hunger cues and an incomplete response to satiety or ‘fullness’. Over time, minor extents of positive energy balance result in overweight and obesity.

The obesity systems map (Fig. 1) identifies at its centre (or ‘core’) problems of appetite regulation and sedentary existence. By applying scientific and other evidence, the map demonstrates that energy balance (or imbalance) is determined by a complex multi-faceted system of determinants (causes) in which no individual influence dominates⁽Reference Vandenbroeck, Goossens and Clemens⁴⁾. The systems map can be divided into seven subsystems to illustrate the inter-play between causative factors: individual biology; individual activity; environmental activity; individual psychology; societal influences; food consumption; food production. Any intervention aimed at one segment will necessarily have an influence elsewhere on the map; the purpose of the map is to enable policy makers to anticipate the likely impact of preventive policies across several segments of the systems map. Altering this complex system to tackle obesity is far from straightforward, particularly as current evidence for effective preventative measures is not strong. There are few international examples of success on which the UK can draw⁽Reference Lobstein and Jackson Leach⁵⁾, although a growing number of demonstrator projects offer promise.

Fig. 1. Foresight obesity systems map demonstrating at its centre (‘core’) the imbalance between appetite regulation and sedentary existence. , Media; , social; , psychological; , economic; , food; , activity; , infrastructure; , developmental; , biological; , medical; —▸, positive influence; - - -▪, negative influence. (From Vandenbroeck et al.⁽Reference Vandenbroeck, Goossens and Clemens⁴⁾.)

Any one intervention will depend on a multiplicity of factors. Furthermore, the map demonstrates that single interventions are likely to have limited benefit; there needs to be a series of interventions at several levels.

This information led Foresight to an approach that links focused initiatives to ‘enablers’ and ‘amplifiers’. An example is the strategy to provide healthier school meals (focused initiative). An ‘enabler’ is the linked policy to improve knowledge and education around food and activity in young adults. An ‘amplifier’ will be the control of advertising high-fat and -salt and sugary foods to children. One level of change will have limited benefit; three levels are likely, with time, to lead to greater benefit⁽³⁾. Nevertheless, the implementation of such strategies may have limited impact on the current generation of adults but lead to long-term benefit in younger generations. The impact across future generations will inevitably rise provided that the approach is sustained and combined with additional options (Fig. 2). The range of options will increase with time as the custom and values around food and activity shifts; future generations seeing benefit as a consequence of sustained strategies. Benefits from integrated and sustained strategies will lead to a progressive decline in obesity prevalence across all generations and an accompanying reduction in obesity-related diseases⁽Reference McPherson, Marsh and Brown²⁾.

Fig. 2. The potential impact of preventive measures against overweight and obesity sustained over a prolonged period of time. →, The positive impact across generations. (From Government Office for Science⁽³⁾; reproduced with permission by Foresight, Government Office for Science.)

Looking to the future: Foresight tackling obesities

The Foresight quantitative scenario modelling predicts a rise in the prevalence of obesity to approximately 60% of the adult male population by 2050⁽Reference Kopelman¹⁾. The predictions for children are equally stark, approximately 70% of girls will be overweight or obese and 55% of boys. Foresight has additionally modelled in the current generation of children the impact of reductions in obesity on the likelihood of diabetes, heart disease and the other commonly-associated medical complications of obesity (Fig. 3). The model demonstrates major benefit to future generations of adults but indicates that this benefit will be most evident in 20–30 years⁽Reference Kopelman¹⁾.

Fig. 3. Predictions of obesity associated disease rates (type 2 diabetes and CVD) during the next 49 years by successful intervention in children currently aged 6–11 years. (From Government Office for Science⁽³⁾; reproduced with permission by Foresight, Government Office for Science.)

Why so long? This time period reflects how long it takes for the serious medical consequences associated with obesity to present; this inevitable delay must not diminish nor divert from a priority of tackling obesity now.

Public health policies involving changes of lifestyle

A concept identified in the Foresight Report is passive obesity, which implies an insidious weight gain in many individuals that results from societal and cultural beliefs⁽³⁾. The concept of passive obesity raises important questions about how society responds to strategies directed at preventing obesity and where society perceives the responsibility for action lies. Individuals who are ambivalent about an issue may react to health-related messages in unexpected and counterintuitive ways. In addition, many individuals do not perceive obesity as an issue that affects them personally and consequently public demand for major action is relatively weak⁽Reference Maio, Manstead and Verplanken^6, Reference Reilly, Dorosty and Emmett⁷⁾. The Foresight Report emphasises the importance of designing options for healthy behaviour, or ‘cues’ for behavioural change, that become normal daily life and thereby influence those individuals not yet ready to make active choices. It is clear that efforts to reverse the rising trend and address the prospect of the increasing health burden and societal costs will be demanding and will necessitate major changes in behaviour, not only in individuals but also in families, communities, organisations and economic markets.

In recent years one of the most successful public health measures has been a requirement to wear seat belts in motor vehicles. The legislation has resulted in a dramatic reduction in injuries and fatalities from road traffic accidents; an immediate, easily-recognised and persuasive benefit⁽⁸⁾. By contrast, it has taken 40 years to realise true benefit from smoking restriction. Smoking and Health, the seminal report on health consequences of smoking, was published by The Royal College of Physicians of London in 1962⁽⁹⁾. The forward-looking recommendations include curbs on the promotion of tobacco products (most particularly to young adults) and the sponsorship of sporting events by tobacco companies, together with recommendations for health warnings on cigarette packs, smoking cessation clinics in hospital practice and a restriction on smoking in public. This last recommendation was introduced in July 2007. Why did effective anti-smoking measures take so long to be introduced? At the outset concerns were expressed about the infringement of personal liberties, the ‘choice agenda’; those with doubts were the most vocal. Moreover, there were compelling financial disincentives against action from the Treasury tax perspective and for the tobacco industry. The latter sought commercial opportunities by introducing ‘safer’ cigarettes (filter-tipped) and arguing that there was no evidence to support stricter legislation. Both the fiscal and personal liberties arguments largely held sway until after the 1997 general election. The publicity and engagement of health professional advice and non-governmental organisations during the 40 years has unquestionably contributed to the progressive decline in smoking prevalence in adults, and an associated reduction in smoking-related diseases throughout the four decades. Societal benefit has happened but over a sustained period of time.

Obesity has much in common with many of the other challenges faced in public health, and many of the wider determinants of health are the same.

The social, infrastructural and environmental factors that need to frame the planning and implementation of policies for obesity reflect many other public health issues, including the management of several chronic diseases, for example:

1. 1. implementing actions despite recognition that the extent of intervention required to achieve a major impact on obesity prevalence may create tensions with broader societal aspirations;

2. 2. stimulating changes in approach when a sense of urgency or policy priority in the wider community is lacking;

3. 3. providing strategic leadership and coordinating action when implementation is complex requires cross-government attention and responsibilities are dispersed;

4. 4. making choices and policy trade-offs;

5. 5. managing risks in the context of limited evidence;

6. 6. managing the risk of unexpected consequences of policy measures⁽Reference Maio, Manstead and Verplanken^6, Reference Chiperfield, O'Brien and Bolderson¹⁰⁾.

The way forward: Foresight Report

The rate of increase in prevalence of obesity is susceptible to a number of external drivers of change that include lifestyle and societal factors⁽Reference Lang and Rayner¹¹⁾. Foresight has developed four scenarios based on differing attitudes to future challenge (‘prepare’ or ‘mitigate’) and whether responsibility is held by society to lie first and foremost at the national, community or individual level.

Analysis of the scenarios suggests that social values and the way society chooses to respond to long-term challenges will be the critical determinant of future scenarios postulated in the Foresight Report. From Foresight's perspective, the greatest opportunity to tackle obesity effectively was found in the scenario that is the most ‘socially responsible and prevention focused’⁽³⁾.

Any action to counter obesity must be aligned with other major policies to maximise the involvement of a broad range of stakeholders. Some policies can act indirectly to reduce the prevalence of obesity through actions motivated by other priorities.

Given the serious challenges identified, obesity can and must be tackled. Foresight has identified five core principles to developing a strategy framework for triggering, and achieving, sustained policy success (Table 1).

Table 1. Core principles for tacking obesity

The challenge is to produce a range of solutions that are effective across different areas of government policy rather than within them and for such policies to be effective by working in a way that society finds acceptable. This strategy will undoubtedly require a greater amount of national debate.