Over a quarter of a century ago, the childhood obesity epidemic started its upswing in high-income countries (1) but it was not until the early 2000s that the issue hit the headlines and really forced the public and politicians to take note (2). That awareness has sparked a surge in research, policies, and programs, but what is the current state of action and, more importantly, where to from here for the prevention of childhood obesity?
At a global level, the most rapid response to the increased awareness of the obesity problem, especially childhood obesity, has come from some of the multinational food corporations. They have formulated or reformulated some of their processed food products toward healthier compositions and increased the promotion of the “healthiness” of these products in their marketing to capture the heightened consumer awareness about obesity. For example, some fast food chains have developed lower energy-dense foods promoted as a “lighter” alternative and, grilled rather than fried choices. Food and beverage ranges promoted as “better for you” or “good-for-you” have appeared and major food manufacturers have been seeking ways to reduce the fat, salt, and sugar from some of their products without altering the taste. However, these corporations are powerful and to date they have been extremely successful in staving off effective regulatory approaches by governments to improving the healthiness of the food environment. The food and advertising industries have launched a plethora of self-regulatory codes on food marketing to children and food sold to schools and the introduction of a large number of different front-of-pack nutrition signposting systems. The intensity of this activity perhaps indicates the importance of industries on avoiding regulations in these areas. The lobbying efforts of the industry to prevent government regulations of food marketing and labeling have probably slowed global progress on obesity prevention.
Multinational government organizations such as the European Union and the World Health Organization continue to provide strong backing (on paper) for action on obesity prevention. Unfortunately, tangible progress in policy leadership, over the last 5 years, has been slow. This slow progress may be the result of a variety of barriers, including national political constraints, pressure from the private sector, competing interests, and priorities and, in the case of World Health Organization, a lack of resources.
International pressure needs to be maintained so that progress will continue within the multinational government agencies. Despite the huge global burden of noncommunicable diseases, the level of urgency and funding support for their prevention remains far below that for other health challenges such as malnutrition, HIV AIDS, and other infectious diseases. To date, the advocacy for obesity prevention has been led by groups such as the International Obesity Taskforce and Consumers International, particularly on food marketing to children (3,4,5), but a strong advocacy alliance across the major global nongovernmental organizations with an interest in obesity prevention has yet to be achieved. The progress over many years of multinational efforts in developing and implementing the Framework Convention on Tobacco Control and the International Code for Marketing of Breast-Milk Substitutes provides the beacon for achieving an International Code on Food Marketing to Children. The other priority for improving the healthiness of food systems is an international agreement on the nutrient profiling of foods (6). This agreement would underpin the definitions needed for many strategies at a national level including: food marketing regulations, front-of-pack nutrition signposts, nutrition education, food and health claims, healthy food service policies, and food supply monitoring.
But, while food systems cross national borders and are becoming increasingly global, the environments that influence physical activity remain much more local (5). The built environment and transport systems tend to be determined within urban areas and, by their built nature, can change only very slowly.
Most countries with high or increasing levels of obesity have already developed national strategic plans. These plans either address obesity itself or are included in broader plans related to nutrition, noncommunicable diseases, healthy eating, and physical activity, or diabetes prevention. The reasons that the plans are largely failing to convert into effective action appear to be twofold: they are dominated by the weaker education and program level strategies (rather than the stronger policy-based approaches), and they are not fully resourced for implementation. Despite all the evidence that noncommunicable diseases dominate the disease burden in most countries and that prevention is more cost-effective than treatment, the primary prevention of noncommunicable disease risk factors such as obesity attracts a miniscule proportion of the governments' health budgets—usually <1%.
There are, however, some valuable examples of governments becoming more serious about creating policies and regulations to improve the healthiness of the food system. These include regulations that restrict some forms of food marketing to children (UK, Sweden, Norway, Quebec), banning trans fats (Denmark and some US cities) and other forms of legal approaches (7). Effective action demands regular monitoring, and action on obesity has long suffered from a lack of routine monitoring of obesity and its determinants. National surveys which include anthropometry may often be 5–10 years apart—imagine trying to manage the economy if the economic indicators were only measured every few years. Systems for monitoring the trends in obesity and its determinants (i.e., key behavioral and environmental indicators) that are fine-grained enough and appropriately translated to the local level are urgently needed and seem to stimulate local action (8).
At a national level, the conversion of the existing strategic plans for obesity prevention into real results will require a significant step up in political leadership. It will require stronger policies to create healthier food and physical activity environments, and much better monitoring systems, especially for childhood obesity.
In general, obesity prevention programs at the community or settings level have shown only limited success. Often the interventions tested are short term, focused on individual behaviors and have a narrow focus (9). There is now widespread agreement that the complex etiology of obesity necessitates a multifaceted approach to prevention (10,11) that incorporates both individual and societal changes. Multi-setting, community-wide strategies provide a comprehensive, equitable, and intergenerational response to the problem. To date, such interventions are showing some success at reducing children's risk of obesity in a number of countries including France, New Zealand, the United States, and Australia (12,13,14,15). Many lessons will emerge from these studies as they delve into the details beneath the topline results to identify what works for whom, why, and at what cost. We are in the early days of identifying commonalities and differences across these studies. Indications are that the established principles of community action are as likely to apply to obesity prevention as to other areas, with importance placed on community ownership, use of existing systems, support for local champions, establishing organizational change over long durations to achieve social change, use of multiple settings to reinforce the messages and so on. The network of Community-based Obesity Prevention Sites Collaboration (CO-OPS Collaboration) in Australia has recently distilled the evidence-base for successful community interventions in general from the health promotion literature and applied it specifically to obesity prevention in a set of Best Practice Principles (16). These principles will be refined over time as more specific empirical evidence on community-based obesity prevention emerges.
Whereas this approach tries to address the multiple factors that affect a community's function and in turn the health of its individual members, it is complex by nature and creates challenges for implementation and evaluation. These challenges include: the need for cross-sectoral engagement and commitment of stakeholders; working in multidisciplinary teams with competing interests; coordination of activities across numerous sectors (e.g., education, health services, child care, nongovernment organizations, service sector, sport and recreation, community development, and urban planning); consolidation of smaller/short-term local initiatives and gaining sufficient funding to implement a community-wide program; and, ongoing organizational and participant engagement to make interventions sustainable.
To address some of these difficulties, obesity prevention interventions should be developed within an integrated prevention model, use a community-based participatory framework and efforts should also be tailored to the broader social, cultural, and environmental contexts (17). An additional benefit of a community-wide approach is its potential to improve the health and development of all community members, beyond the target group and shift community norms and standards in an incremental way to be more health promoting (e.g., improved quality of foods provided to children at school and in child care, use of active transport to school, and fundraising activities not related to unhealthy foods). This approach can create sustainable changes across the community that can have population-level effects and potentially reduce the socioeconomic gradients that currently exist for obesity (15) and many other health outcomes. Programs and policies at a community level are much more rapidly enacted than they are at a state or national level and this is one of the key benefits of local action. However, the actions within schools, primary care clinics, early childhood settings and so on often depend on the energy of a few champions or short-term funding and this carries the risks of piecemeal uptake and variable sustainability. Naturally, the combination of “top down” policy and funding approaches with “bottom up” community action would give the best outcomes, but in the real world, progress occurs when (usually imperfect) opportunities for action are taken. Currently community appetites for action seem much greater than the national political appetites.
Physical activity environments, such as recreation spaces and facilities as well as footpaths and public transport, are under a significant degree of local control (e.g., through local councils). Sports and activity programs are about local engagement in local places and thus are an important and visible part of community cohesion and social functioning. By contrast, the local food environment is highly responsive to national and global influences and local councils traditionally consider that their only role with the food environment is through food safety.
To progress our knowledge of effective prevention strategies for childhood obesity prevention in a variety of contexts, intervention programs must include rigorous evaluation involving multiple levels and various settings. Evaluation is often made difficult by the lack of a population monitoring system and/or sophisticated data linkage structures to enable routinely collected data to be used for program evaluation.
Much of the current obesity research is aimed at unpicking the determinants and mediators of obesity—genetic, metabolic, psychological, behavioral, and demographic. This “problem-oriented” research (“what is to blame?”) can be valuable but surprisingly, as Robinson and Sirard state, understanding the determinants does not necessarily help us very much in understanding the solutions (18). For example, reductions in occupational physical activity may have contributed to the increasing obesity epidemic, but what does that tell us about the action needed—bring back the pick and shovel for roadwork and reduce mechanization and computerization in the workplace? Specific “solutions-oriented” research (“what do we do about it?”) is needed to evaluate interventions but we also need to look more broadly and apply the lessons learned from the solutions created to address other epidemics—tobacco, road deaths, infectious diseases, occupational injuries, cardiovascular disease and so on. A greater emphasis from research funding bodies on solution-oriented research is starting to occur and, if this becomes more widely applied, it will stimulate the creation of the much-needed evidence to inform practice and policy. Robinson and Sirard (18) propose a “litmus test” to apply to proposed research studies to maximize the efficiency of the research enterprise. They suggest that a research study should only be performed if: (i) you know what you will conclude from each possible result (whether positive, negative, or null); and (ii) the results may change how you would intervene to address a clinical, policy, or public health problem such as obesity.
The new imperative for obesity prevention research is to work out how to take the many learnings (successes and failures) emerging from demonstration projects and intervention studies and to develop methods for implementing them across populations using a “whole-of-system approach” (19,20). This will help to create the evidence of both what is effective and how to implement effective programs. Due to the complexity of the contexts (different age-groups, localities, ethnicities, and levels of disadvantage), a single best practice “program” is unlikely to emerge. Rather, knowledge of the strengths and weaknesses of elements of various programs across settings will emerge. The major current approaches within obesity prevention research use “trial-based” methods where the focus is on demonstrating the effectiveness of defined interventions. However, to more rapidly advance the field, additional approaches of continuous quality improvement are needed, in which the critical research questions focus on deriving the most effective processes for increasing the scale and quality of interventions (21). While continuous quality improvement has been used for over 50 years in industry (and more recently in health services research (22,23)), its application to health promotion is limited (23,24,25), especially within the complex, multi-setting systems needed to prevent obesity. New obesity prevention “systems” with efficient knowledge translation, monitoring, evaluation, and health service delivery mechanisms geared toward prevention should become a key component of health service and government planning, policy development and funding allocation.
One much neglected, but exceedingly important area of obesity research is the sociocultural influences around food, physical activity, and body size perceptions. There is a 100-fold range in the prevalence of obesity in women between Bangladesh (0.7%) and Tonga (70%) with everything in between (26) and whereas some of these differences in population prevalence can be explained by economic differences or definitional problems of using BMI, sociocultural factors are likely to explain a large proportion of this variance. This has major implications for obesity prevention interventions. For example, the very important social values of friendship, respect, hospitality, and reciprocity often involve giving and receiving food, but in some cultures, the type and amount of food involved is more heavily weighted by these cultural values resulting in a socially driven overprovision and overconsumption of food. Such powerful, embedded forces are unlikely to be easily changed, yet to be successful in preventing obesity in those cultural groups at risk, the obesogenic manifestations of the social values will need to change. Our current research paradigms have barely acknowledged the existence of these highly influential sociocultural moderators of obesogenic behaviors let alone worked on how the manifestations can be altered while preserving the essential underlying social values. Crosscultural research will be critical for identifying and learning from those populations with apparent sociocultural “obesity protection” or “obesity predisposition”. For example, the protective effects of Japanese cuisine and culture against obesity will only become clear through comparative studies. Translating the findings from sociocultural studies into social marketing approaches, which can potentially influence social norms, is one of the next major challenges for those populations with apparent sociocultural predisposition to obesity. Ethnic differences in obesity prevalence are often greater than socioeconomic differences and so understanding how to achieve these sociocultural changes has enormous implications for achieving the equity goals of obesity prevention.
Another solution-oriented methodology, which is now being applied to obesity prevention, is the use of computational modeling of the cost-effectiveness of various interventions. When policy-makers want to take action to reduce obesity it is not helpful to say that the best possible evidence (randomized controlled trials) is too limited, too short term, and largely negative. A modeling approach, such as that used in the Assessing Cost-Effectiveness (ACE) Obesity study (27) applied the best available evidence (with uncertainty limits) to specified obesity-related interventions that the policy-makers involved thought could be implemented. The outcomes are estimates of likely costs and population impacts of promising interventions along with comments about other policy considerations (“second-stage filters”) such as feasibility, acceptability, sustainability, effects on equity, and other positive or negative effects. The models can range from very simple (e.g., costs per BMI unit reduced) through to very sophisticated where population impacts are assessed in utility terms, such as disability-adjusted life-years lost, to allow comparisons with interventions for other health conditions and costs are in net terms after subtracting cost savings (27,28). The range of cost-effectiveness of interventions is often very wide (e.g., over two orders of magnitude for ACE Obesity) giving policy-makers strong guidance on the most and least cost-effective interventions.
Overall, there has been a marked increase in the efforts to prevent obesity over the past 5–10 years; however, we are still virtually at the starting line. It is salutary to recognize that it took tobacco control >50 years to achieve its current variable global success. Tobacco is a single, nonessential product with clear evidence of harm and strong evidence of intervention effectiveness, whereas, obesity is far more complex. Thus the obesity prevention effort will need to be many times greater than tobacco control efforts just to approach a similar pace. Let us hope that the next 10 years will see a much greater policy (and research) response to making the food and physical activity environments less obesogenic so that the health promotion efforts to encourage healthier choices have some chance of working.