In this paper, the author will examine the complex interaction of social, economic, biological and environmental determinants of health that may explain the recent explosion and shifts in demographic trends of this world wide problem and briefly explore lifestyle and behavioural factors that may create particular risks. This will be followed by discussion about causes, complications and treatment options of childhood obesity.

The author will review and analyse determinants and health policy initiatives, critically appraise various global, national and local strategies, initiatives and interventions which are aimed to prevent obesity in childhood and also examine how they are linked to conventional health promotion models and theories.

By critically examining the range of interactions and existing initiatives, the author seeks to propose appropriate interventions to tackle the growing challenge of childhood obesity.

Key words: childhood obesity, inequalities, policy, strategy, prevention, health promotion

DEFINITION

Obesity/Adiposity is defined as ‘a condition characterised by excessive body fat’. Body fat can either be stored predominantly around the waist or around the hips.

Body Mass Index (BMI) is used to measure obesity and defined as:

bodyweight(Kg) (Keys et al. 1972)

height(m)2

BMI is useful in clinical practice and in epidemiologic studies, but has limitations and in his report (2004), Wang reported that although a high BMI-for-age is a good indicator of excess fat mass, BMI differences among thinner children can be largely due to fat-free mass.

Two international datasets that are widely used to define overweight and obesity in pre-school children are the International Obesity Task Force (IOTF) reference and WHO standard (WHO Child Growth Standards, 2006). None is superior to the other and both tend to underestimate or overestimate the prevalence when used on the same population (Monasta et al. 2010).

Thresholds for obesity in children in UK (and Scotland) are measured by referring to

UK National BMI classification system that uses reference curves based on data from several British studies between 1978 and 1990(ScotPHO 2007).

Children are classified as overweight or obese using the 85th and 95th percentiles as cut points.

PREVALENCE & trends

Obesity has become an epidemic in many parts of the world and surveys over the last decade have documented the rapidly increasing prevalence of obesity and overweight among children along with rising socioeconomic inequalities (WHO factsheet 2006; Lobstein 2004).

The latest WHO report (Mercedes, Monika and Elaine, 2010) based on surveys from 144 countries estimates that globally, 43 million children (including 35 million in developing countries) are overweight and obese and another 92 million are at risk of overweight. This corresponds to a prevalence increased from 4.2% in 1990 to 6.7% in 2010.

In England, 2008 figures showed 16.8% of boys aged 2 to 15, and 15.2% of girls were classed as obese, an increase from 11.1% and 12.2% respectively in 1995(Health and Social Care Information Centre, 2010).

Scotland has one of the highest levels of obesity in OECD countries; only the USA and Mexico having higher levels. In 2008, 15.1% children were obese and 31.7% were overweight. This is predicted to worsen even with current health improvement efforts (Scottish Govt. report, 2010).

Amidst this doom and gloom scenario are recent reports showing trends in overweight and obesity prevalence have stabilized or reversed in France (Lioret et al.2009), Switzerland (Aeberli, 2008) and Sweden (girls 10’11 years) (Sjoberg et al. 2008). In the US too, the obesity epidemic may be stabilising (US CDC Report, 2008; Ogden et al.2010) but it is too early to know whether the data do reflect a true plateau (Cali and Caprio, 2008).

Similarly, in England, trends in overweight and obesity prevalence have levelled off after 2002 (Stamatakis, Wardle and Cole 2010).

COSTS

Healthcare costs of obesity are only a fraction of overall costs to society (McCormick 2007) due to loss of employment, production levels and premature pensions and extra burdens on businesses.

Obesity is responsible for 2’8% of health costs in Europe and other developed countries (WHO 2007).

Total cost to NHS Scotland of obesity in 2007/8 was about ‘175 million and expected to double by 2030. The total cost to Scottish society of obesity in 2007/8 was in excess of ‘457 million and expected rise to ‘0.9 billion-‘3 billion by 2030 (Scottish Govt. report 2010).

In England, updated estimate of direct obesity-related costs to NHS is ‘4.2 billion and this may double by 2050. Cost to the wider economy is in the region of ’16 billion, and will rise to ’50 billion per year by 2050 if left unchecked (UK Public health report).

INEQUALITIES

Although an earlier review by Parsons et al.(1999) reported no clear relationship between socio-economic status (SES) in early life and childhood obesity (but confirmed a strong relationship with increased fatness in adulthood), a more recent systematic review (Shrewsbury & Wardle 2008) supports the view that overweight and obesity tend to be more prevalent among socio-economically disadvantaged children in developed countries.

Similar patterns are shown in data from England (Stamatakis, Wardle and Cole 2010; Law, 2007) and Scotland (Scottish Govt. report, 2010).

However, trends vary within different ethnic populations (Wang and Zhang 2006) e.g., a review by Caprio et al. (2008) concluded higher prevalence in non-Caucasian populations in US.

Earlier reports (Wang, 2001) revealed that the burden of this problem was mainly in wealthier sections of the population in developing nations. In contrast, later reports (Lobstein, Baur and Uauy 2004; Wang and Lobstein 2006) indicate that prevalence is rising among the urban poor in these countries, possibly due to their exposure to Westernized diets overlapping with a history of undernutrition.

The reasons for the differences in prevalence of childhood obesity among population groups are complex, involving race, ethnicity, genetics, physiology, culture, SES including parental education, environment, and interactions among these determinants (Law et al.2007; Sonia et al. 2008; Townsend and Ridler, 2009).

CAUSES and COMPLICATIONS

The development of obesity in childhood and subsequently in adulthood involves interactions among multiple factors (the obesogenic environment):

* personal (e.g., dietary and physical activity patterns & preferences; disability)

* environmental (e.g., home, school, and community)

* societal (e.g., food advertising, social network, and peer influences)

* healthcare-related (access & availability)

* physiological (e.g. genetics, race and ethnic, psychological, metabolic)

Although genetic factors can have an effect on individual predisposition (Rankinen et al 2002), rapidly rising prevalence rates are explained by perinatal and environmental factors (Wojcik & Mayer-Davis 2010).

Key perinatal factors for childhood obesity are maternal overweight before, during and after pregnancy (Oken at al. 2007; Whitaker and Dietz 1998), smoking (von Kries et al. 2002) and bottle-feeding (Gillman et al. 2001). The mother’s dietary habits and level of physical activity are also important factors (Wojcik & Mayer-Davis 2010).

The First Law of Thermodynamics implies that weight gain is secondary to increased caloric intake and/or decreased energy expenditure (Anderson and Butcher 2006).

Decreased physical activity levels associated with sedentary recreation (video and computer games), mechanised transportation (less walking), and increasing urbanization (limited opportunity to physical activity) (Trost et al. 2001; Gordon-Larsen, McMurray and Popkin 2000) are associated with increased risk of obesity.

Children with disability are at a greater risk to develop obesity (Reinehr et al. 2010) due to several reasons including health issues and restricted access to physical activity.

Television viewing is thought to promote weight gain not only by decreasing physical activity, but also by increasing energy intake (Epstein et al. 2008). Also, television advertising could adversely affect dietary patterns at other times throughout the day (Lewis and Hill, 1998).

Psychosocial factors are linked to dietary and physical activity behaviours that define energy balance. Children who suffer from neglect and depression are at increased risk for obesity during childhood and later in life (Johnson GJ et al. 2002; Pine DS et al. 2001). On the other hand, social support from parents and others increases participation in physical activity of children and adolescents (Sallis, Prochaska, Taylor 2000).

There is evidence that breast milk in infancy may moderately protect against overweight in childhood (Davis 2001) while intake of foods with high glycemic index, sugar sweetened soft drinks and ‘fast foods’ are associated with increased risk and prevalence of childhood obesity (Ludwig et al. 1999; Ludwig et al. 2001; French 2001); however, long term trials are needed to corroborate this association. Also, eating out (Zoumas-Morse et al. 2001) appears to be an important contributory life style factor.

Excessive fat in the diet is believed to cause weight gain (Jequier 2001); however, this association is not consistently shown in epidemiological studies (Atkin L-M Davies 2000; Troiano 2000). Moreover, the type of dietary fat consumed more important than total fat consumption (Kris-Etherton P et al. 2001).

Lustig (2006) proposes that the relationship between changes in the environment and neuroendocrinology of human energy balance is complex. The author explains that behaviours of increased caloric intake and decreased energy expenditure are secondary to obligate weight gain that is due to associated hyperinsulinemia, leptin antagonism and interference with normal satiety.

Childhood obesity is a multisystem disease with potentially serious complications:

* Cardiovascular risk factors along with insulin resistance have been documented in children as young as five years old (Young-Hyman et al. 2001).

* Several studies suggest that childhood overweight/ obesity is associated with increased mortality risk in later life (Gunnell 1998; Dietz 1998).

* The rapidly rising prevalence of type 2 diabetes in obese children is worrying in view of the vascular complications (heart disease, stroke, limb amputation, kidney failure, blindness) (Ludwig and Ebbeling 2001; Sinha et al. 2002). These risks appear to be higher in non-Caucasians (Goran , Ball and Cruz 2000)

* Adverse psychosocial effects [more severe in white girls (Richard 2000)].

Treatment

Effective intervention is essential because obese children are likely to face substantial health risks as they mature (Cali and Caprio 2008; Speiser et al.2005). Further, as healthcare costs of this problem are rising (Wang and Dietz 2002); intervention is required to prevent morbidity in adulthood while effective tools for primary prevention are being developed.

Spear et al. (2007) reviewed the evidence about the treatment options in primary care, community, and tertiary care settings and proposed a comprehensive 4-step approach for weight management. This view is supported by a similar review by Uli, Sundarajan and Cuttler (2008).

Several large reviews of lifestyle (i.e. dietary, physical activity and/or behavioural therapy) interventions for treating childhood obesity (Luttikhuis et al. 2008; Freeman 2008; Epstein et al. 1985) concluded that family based combined behavioural and lifestyle interventions can produce significant reduction in overweight in children and adolescents.

Although Golan et al. (1998) suggested that targeting exclusively parents for change was superior to targeting only children for change, behavioural approaches involving both parents and children in the framework of a combined lifestyle intervention appear to be more effective (Wilfley et al. 2007; Epstein 1994; Bronwell 1983).

Moreover, intensive lifestyle intervention (with mandatory caloric restriction, multiple counselling sessions and clinic visits and daily exercise) appears to be more effective (Nemet at al. 2005) than standard lifestyle intervention (Epstein et al. 1980).

Although there is no consistent evidence to show the effectiveness of decreasing sedentary behaviour in terms of reducing television viewing (Dennison et al. 2004; Gortmaker et al. 1999), restricting TV food advertising to children may be one of the most cost-effective population-based interventions (Magnus et al. 2009).

In obese adolescents, treatment with orlistat or sibutramine is sometimes used as adjunct to lifestyle interventions. However, these drugs have the potential for significant side effects and this approach needs close monitoring and follow-up (Freemark 2007).

Data indicate substantial weight loss after bariatric surgery in morbidly obese adolescents but potential serious complications (Lawson et al. 2006; Uli et al. 2008) necessitating close follow-up and dedication to a specialized dietary regimen (Shen, Dugay & Rajaram 2004) for successful results.

Role of schools

Systematic reviews of random controlled trials (RCT) by Reilly and McDowell (2003) and Summerbell et al. (2005) concluded that the evidence base for interventions in childhood activity or school-based initiatives for prevention of obesity remains limited.

In contrast, Thomas et al. (2004) in their review put forward a more positive conclusion. Similarly, Flynn et al. (2006) and Doak et al. (2006) reported favourable outcomes in nearly all trials they reviewed.

Interestingly, in an analysis of school-based programs, authors from National Institute for Health and Clinical Excellence (NICE), UK (2006) indicated that the evidence does not convincingly support the multidisciplinary ‘whole school’ approach advocated by UK National Healthy Schools Program.

Nonetheless, Connelly, Duaso & Butler (2007) in their review of RCTs have supported a decisive role for obligatory provision of aerobic physical activity in schools coupled with nutritional education and skills training. Finally, Kropski, Keckley & Jensen’s review (2008) concludes that although evidence is limited, schools play an important role in prevention strategies and different techniques directed at boys and girls for a program may have more impact.

HEALTH PROMOTION MODELS RELATED TO PREVENTION OF CHILDHOOD OBESITY

Knowledge’Attitude-Behaviour model proposes that as knowledge accumulates, changes in attitude are set off resulting in gradual change in behaviour. The model assumes that a person is rational (Barnowski 1997). However, evidence shows that most people in most situations do not exhibit objectively ‘rational’ behaviour (Shafir & LeBeouf 2002).

The commonest application for promoting change by use of this model has been the provision of information in school curricula.

Although knowledge partially mediates a relationship between goal setting and self-efficacy, it is not related to a change in the behaviour (Schnoll & Zimmermann 2001) or to changes in physical activity behaviour (Rimal 2001) except perhaps in limited subsets of people (Wang & Biddle 2001). Besides, no research has demonstrated that knowledge-based intervention programs lead to behavioural change (Contento et al.1995).

Thus, the KAB model, independently, is an inadequate tool in promoting dietary or physical activity-related behavioural change.

Behaviour Learning Theory (BLT): According to BLT, behaviours are performed in response to stimuli, and the frequency of such behaviour after a stimulus will increase if the behaviour is reinforced (Skinner 1938).

A modern version of BLT, the Behavioural Economics model (Epstein 1999) suggests behaviour is the result of benefits and costs where benefits are reinforcers. Obese people obtain more reinforcing value from food than others (Saelens & Epstein 1996) whereas physical activity was found to be more reinforcing among non-obese people (Epstein et al.1991).

Further, the distance to a preferred physical activity reduced the reinforcing value of the preferred activity (Raynor, Coleman & Epstein, 1998). Thus, obese people tend to find behaviours that lead to obesity more reinforcing.

Saelens & Epstein (1988) applied the model successfully in obtaining increased physical activity. However, application of reinforcers procedures on controlling behaviour is challenging and not all parents may be able to do it.

HEALTH BELIEF MODEL: The Health Belief Model helps explain utility of health services and has been widely applied to health-related behaviours (Rosenstock 1966; Janz, Champion & Strecher 2002). The model explains health actions through the interaction of sets of beliefs: perceived susceptibility, perceived seriousness perceived benefits and disadvantages and cues to action.

There is evidence that promptness to cues varies depending on their source (Jones, Fowler & Hubbard 2000) and perceived importance (Strychar et al 1998). Perception of susceptibility also varies between populations and may not translate into intention to change behaviour (Humphries & Krummel 1998) or may do so only weakly (Leventhal, Kelly & Leventhal 1999).

A meta-analysis study by Witte and Allan (2000) of fear-based communications revealed that they can induce behavioural change by affecting individual’s perception of threat. However, because children and adolescents tend to see themselves as immortal, the concept of fear and threat and perceived risk, susceptibility and seriousness are not useful in this age group. HBM may become more relevant if the perceived seriousness of and susceptibility to obesity becomes alarming (Baranowski 2003).

Social Cognitive Theory (SCT) proposes (Bandura 1986) that behaviour is a function of continuous mutual interaction between the environment and the person. Changing behaviour revolves around the ability to exert self-control which is motivated by outcome expectancies because people desire to achieve positive outcomes and avoid negative outcomes.

The theory has been tested with a number of behaviours and number of target populations (Bandura 2004; Sharma, Wagner & Wilkerson 2006).

Programs based on SCT have resulted in some changes as reported in a review by Sharma (2005) of school-based interventions for preventing childhood obesity where SCT was the most popular basis of intervention. However, the predictability of SCT concepts for understanding diet and physical activity among children (Baranowski, Cullen & Baranowski 1999) is poor ‘ it could be that the concepts are too complex to influence the behaviours of children. Children may not be expected to or able to exercise much control over their diet or physical activity and therefore environmental variables like parenting (Cullen et al.2003) and availability of food and physical equipment (Hearn et al. 1999) are more significant.

Theory of Reasoned Action (TRA) or Theory of Planned Behaviour (TPB) (Fishbein and Ajzen 1975; Madden & Ajzen 1986) has been applied in many health behaviours (Sutton 1997). It proposes that attitudes, perceived social norms and perceived behavioural control predict behavioural intentions which in turn influence behaviour (Armitage & Conner 2001). However, some behaviours are not under a person’s control (e.g., healthier food choices may not be available at neighbourhood stores) which is a limitation of TRA. Further, it may be difficult to predict social norms (Terry & Hogg 1996). Goding & Kok’s review (1996) reported that the efficiency of the theory varies between health-related behaviour categories. TPB model has been applied to childhood obesity prevention programs with results showing both good (Andrews, Silk & Eneli 2010) and mixed (Fila & Smith 2006) predictability.

Transtheoretical model (T)

This model proposes that health behaviour change involves progress through six stages of change: precontemplation, contemplation, preparation, action, maintenance, and termination and describes 10 processes that enable this change (Prochaska et al.1992). The model has been successfully applied in addictive disorders like smoking (Velicer at al. 1998) but has limitations when applied in the treatment of eating and weight disorders (Wilson & Schlam2004).

T has been applied to obesity with studies reporting both good (Sarkin et al. 2001) and poor predictability (Macqueen, Brynes, and Frost 2002).

Ecological and Social Ecological Models

The complex etiopathogenesis of childhood obesity suggests that social ecological (SE) models may yield creative lasting solutions (Huang and Glass 2008).

The SE model initiated by Bronfenbrenner (1977) and subsequently developed for understanding obesity by Davison and Birch (2001) and Story et al. (2008) propose that the individual is shown as contributing their cognitions, skills and behaviours, lifestyle, biology and demographics, while embedded in other circles representing the social, physical and macro-level environments to which they are exposed including families, neighbourhoods and the larger cultural environment.

Swinburn, Egger & Raza (1999) have described the ANGELO (analysis grid for environments linked to obesity) framework which is an ecological model for understanding the obesogenicity of environments.

The International Obesity Task Force’s model is also based on this theory and describes societal policies and processes with direct and indirect influences on body weight (Kumanyika et al. 2002) as shown here:

An ecological approach is also the basis of the Canadian model: the Child Health Ecological Surveillance System (CHESS) represents a prototype for addressing childhood obesity through a local approach, with possible generic applications and global implications (Plotnikoff 2010).

Global, regional and national prevention strategies

As part of the response to fight the childhood obesity epidemic, WHO (2004) developed the Global Strategy for Diet, Physical Activity and Health (DPAS) and produced a range of tools to assist Member States and stakeholders to implement DPAS. It emphasised that National plans should have achievable short-term and intermediate goals.

A schematic model developed by WHO (2008) for implementation and monitoring of DPAS provides the basis for a framework for action and explains how supportive environments, policies and programmes can influence behaviour changes in a population and have lasting environmental, social, health and economic benefits. The monitoring and evaluation component provides the foundation for promotion, policy development and action.

Figure 2: Implementation framework for the Global Strategy on Diet, Physical Activity and Health

The model emphasises the need of right mix of upstream (socio-ecological) approaches aim to shape the economic, social and physical (built and natural) environments, midstream ( lifestyle) approaches aim to directly influence behaviour (reducing energy intake and increasing physical activity), and downstream (health services) approaches support health services and clinical interventions (Sacks, Swinburn and Lawrence 2008).

Population-based prevention strategies developed in the context of a ‘social determinants-of-health’ approach and implemented both at the national level and locally in school and community-based programmes help to change the social norm by encouraging healthy behaviours. Further, the responsibility of tackling health risks when transferred from the individual to governments (and decision-makers) helps to address associated socio-economic inequalities (WHO 2009). To be successful, action by multiple stakeholders, coordinated by strategic leadership is vital.

Global surveillance tools recommended for growth assessment are Child Growth Standards (WHO 2006) and the Global School-based Student Health Survey (GSHS) (WHO 2009).

WHO has identified key challenges of population based prevention strategies:

* Globalization of food systems creating economic and social drivers of obesity through changes in the food supply and people’s diets,

* Poorly designed urbanization

* Deepening socioeconomic inequalities

* Obesity in those with physical and/ or mental disabilities.

* Cost-effectiveness: A model-based analysis by the Organisation for Economic Cooperation and Development (OECD) and WHO, suggests that combined approaches which address multiple determinants can improve efficiency of intervention programmes (Sassi 2009).

Based on The Ottawa Charter for Health Promotion (WHO 1986), key elements of global prevention strategies based are:

* Work at multiple settings – schools, after-school programmes, homes and communities and clinical settings

* Identify and include vulnerable groups.

* Use of correct approach, or better, a mix of approaches for a given situation is crucial along with concern of country- and community-specific factors, such as availability of resources and/or socioeconomic disparities.

* Set priorities and targets and engage with all stakeholders in a transparent manner.

* Allow public access to information on partnerships and disclose potential conflicts of interest to minimize conflicts of interest.

* Effective programme implementation and sustainability ‘ long term planning and budgeting, as well as identifying cost-effective interventions such as the ACE-Obesity project (Carter et al. 2009) is vital..

* Creative funding to warrant long-term sustainability; this might include the development of strategies to uncouple funding by the private sector from direction setting and intervention selection.

The International Obesity Taskforce (IOTF) have developed in consultation with WHO a set of (Sydney) principles defined to cover the commercial promotions of foods and beverages to children and guide action on changing marketing practices them (2007). The principles aim to ensure a degree of protection for children against obesogenic foods and beverages.

In November 2006, European Union (EU) Member States adopted the European Charter on Counteracting Obesity, which defines WHO policies and action areas at the local, regional, national and international levels for all stakeholders in government and private sector (food manufacturers, advertisers and traders) and professional, consumers’, international and intergovernmental organizations.

To encourage individual behavioural change, the strategy ‘Healthy Weight, Healthy Lives: A Cross-Government Strategy for England’ (2008) has been developed with following key features:

* Children, healthy growth and weight

* Promoting healthier food choices

* Building physical activity into people’s lives (Healthy towns build on the EPODE model ( Borys 2006)

* Creating incentives for better health

* Personalised advice and support

Policy drivers include national policy changes (e.g. increased support for surveillance, promotion of breast feeding, bans on unhealthy food advertisements, social marketing campaigns); changes to the food supply (e.g. development of a healthy food code, introduction of front-of-pack labelling, limits on fast-food restaurants near schools and parks, increased supply of fresh fruit and vegetables to stores in deprived areas); development of a national physical activity plan in part (tied to the 2012 Olympics with the purpose of improving built environments); and improved nutrition-related health service provision). The project is led by an intergovernmental team, and has provided resources for local authorities and National Health Service (NHS) and established knowledge-sharing points. Partnerships within government have been strengthened in order to leverage funds and to integrate projects into existing strategies and programmes.

* Facilitate a national dialogue on society’s response to the epidemic of excess weight

* Develop a comprehensive marketing programme

* National prioritisation and clear accountability within Government

* Build ‘up Staff skills and capabilities

* Extensive support and guidance for PCTs and local authorities

* Clear Whitehall decision-making and setting aside financial resources

The Government and Convention of Scottish Local Authorities (COSLA) have developed a Route Map to prevent overweight and obesity (2010) for decision-makers working with their partners, NHS Scotland and businesses to develop and subsequently deliver lasting solutions. The Government has targets to reduce the rate of increase in the proportion of children with unhealthy BMI by 2018 but none yet for obesity or weight management.

Policies for prevention are directed at reducing energy consumption, increasing physical activity and minimising sedentary behaviour, creating positive health behaviour through early life interventions and building healthier work place environments.

Policy drivers include:

1. For obesity management:

* The HEAT (health improvement, efficiency, access, treatment) H3 target for child healthy weight intervention programmes

* Counterweight (evidence based obesity management in Primary Care)

* Scottish Enhanced Services for childhood obesity in the Western Isles

2. For obesity prevention

* Implement initiatives in Let’s Make Scotland More Active

* Recipe for Success: Scotland’s National Food and Drink Policy

* Eight Healthy Weight Communities programmes across Scotland

* Seven Smarter Choices Smarter Places active travel demonstration towns

* The ‘Take Life On’ national social marketing campaign aims

* Beyond the School Gate and NHS Health Scotland’s Healthy Weight Outcomes Framework will provide guidance to help create health-promoting communities

In addition, there are several national programs directed to a ‘Greener, Healthier, Smarter, Safer and Stronger Scotland’ which are likely to have indirect contribution to tackle overweight and obesity.

CONCLUSION:

The essay emphasises the rapidly increasing burden of childhood obesity with associated population profile changes and increasing social inequalities. It explains the complex multifaceted and interlinked causal pathways that form the obesogenic environment.

Community and school-based obesity intervention and prevention programmes are described and the role of research protocols in gathering evidence for such interventions and their usefulness is briefly explored. Existing global, regional and national prevention and implementation strategies to fight childhood obesity are specified.

The author has reviewed and compared various forms of prevention strategies and interventions (singly and in combination) that are in practice and in which conditions they are effective. The important role of socio-economic development and government policies on urban planning, environment, transport, and education and vitally, the agriculture and food industry can be designed and implemented to achieve reduction of obesity is emphasised.

Evidence for effective prevention of childhood obesity is strongly challenged at present. Further research is required to identify best practice procedures for public health policies that are cost-effective, culturally sensitive, deal