A clinician's guide to obesity prevention in the UK

Obesity prevention benefits everyone

Reducing obesity can support healthier, wealthier and more equitable communities. Health is improved by reducing morbidity and mortality from obesity and related diseases, such as cancer, cardiovascular disease, diabetes and poor mental health.⁵ Regional and national economies are improved by reducing obesity-related healthcare and social costs (eg loss of productivity, absenteeism, presenteeism and early retirement), estimated in the UK at £698 per person in 2019 and predicted to reach £1,691 per person (£127 billion or 2.41% gross domestic product) by 2060.⁹ Places and the planet also benefit from obesity prevention: the changes we need to make to how we live, learn, work, eat and play can drive progress on 13 of the 17 Sustainable Development Goals, developed and agreed by the United Nations General Assembly in 2015 to deliver ‘peace and prosperity for people and for the planet’.¹⁰

Obesity in the UK is an entrenched public health issue with stark inequalities

The percentage of adults with obesity in the UK is now at 26%, having increased gradually from 15% in 1993. This trend is expected to continue.¹ The more deprived an area, the more people there are living with obesity, and this difference starts in childhood. Rates of childhood obesity have risen sharply in recent years, more so in the most deprived areas. In 2020/2021 in England, rates of obesity in poorer areas among 4-year-olds were more than double that of richer areas (6.2% versus 13.6%). The gap was wider still by age 10 (13.5% versus 31.3%) and persists through adulthood (19.2% versus 36.8%).¹ This difference is not inevitable. What has changed since 1993, and what differs between affluent and deprived areas, is not people's genes or willpower but the proliferation of environmental factors that increase an individual's likelihood of gaining weight.⁶ Considering the significant inequalities across the UK, obesity prevention should follow the principle of proportionate universalism; the resourcing and delivery of universal services at a scale and intensity proportionate to the degree of need, aiming to improve the health of the whole population while simultaneously improving the health of the most disadvantaged fastest.¹¹

A combined environmental–behavioural approach to obesity prevention

Most people know that they should eat a healthy diet and be active, so why don't they? We should approach this question with compassion and kindness. People are rationally operating within work, leisure and transport contexts where healthy-weight behaviours are increasingly difficult.⁶ For individuals who have successfully lost weight, physiological changes, such as appetite upregulation and reduced resting energy expenditure, can then act to magnify the influence of these environmental factors on weight regain.¹² Understanding which aspects of the obesogenic environment influence which component of behaviour can help when planning and prioritising interventions.⁸ Fig 1 provides a framework for mapping how the building blocks of health and public health interventions impact an individual's capacity, opportunity and motivation for healthy-weight behaviours (the ‘COM-B model’).⁸

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Fig 1.

Framework for mapping how the building blocks of health and public health interventions influence an individual's capacity, opportunity, and motivation for behaviour change. Developed from the social determinants model developed by Dahlgren and Whitehead,³⁶ a health map for the local human habitat developed by Barton and Grant,⁷ and the COM-B framework by Michie et al.⁸

The COM-B model (see Box 1 for a summary) posits that behaviours require sufficient support across all components (capability, opportunity and motivation).⁸ For example, to swim regularly, you need to be able to move your arms or legs (physical capability) and know how to swim (psychological capability). You then need to have access to water (physical opportunity) and the time and money to get there (socioeconomic opportunity). Finally, you need to make a deliberative plan to go swimming (reflective motivation), and the in-the-moment desire to go swimming over anything else (automatic motivation). Obstruct one component (eg losing pool access because of unaffordable price rises (opportunity)) and the behaviour is prevented. Therefore, diet and activity, the behavioural drivers of obesity, are supported or impeded depending on the balance of enabling and constraining factors in each component.

An environmental–behavioural approach draws these enabling and constraining factors from individuals' building blocks of health, which can be considered in three broad contexts: socioeconomic, environmental and commercial. It is easy to understand how some of these contexts constrain opportunities for health. Education and income influence the resources available to engage with, and benefit from, health opportunities, such as whether we have time to exercise or can afford particular food¹¹: consistently following the UK Government's Eatwell Guide costs nearly three times the average person's weekly food spend.¹³ Our physical environments (our homes, workplaces, schools, and neighbourhoods) determine our access to opportunities to be active using transport networks (walkability, cycle lanes or public transport), leisure infrastructure (gyms or sports fields) and nature/greenspace,^6,14 as well as the relative availability and proximity of healthy versus unhealthy food. Other ways our contexts influence health are less obvious. Social contexts (family, friends and culture) influence our food choices and physical activity levels.⁷ A range of industry-led factors also influence our ability to stay healthy, such as the marketing and availability of cheap, high-density, low-nutrient food.^15,16 Known as the commercial determinants of health, the practices of some industry actors, particularly in harmful-product industries, such as tobacco, alcohol, and ultra-processed food, have been associated with increasing rates of ill health, inequality and obesity.¹⁶

The Institute for Fiscal Studies reports the UK as one of the most geographically unequal countries in the developed world, with significant disparities in economic performance and living standards.^17,18 Place-based disadvantage means that people living in more deprived communities have fewer opportunities to be healthy.¹¹ The most deprived areas have the highest density of fast-food outlets¹⁹ and one fifth of the greenspace.¹⁴ Living on a busy road might mean that it is unsafe to cycle or walk to school. Similarly, living in a high-crime area might make it feel unsafe to exercise outside after dark. Disadvantaged regions generally experience higher unemployment, less access (digital and transport) to economic opportunities, and lower educational attainment, social mobility and community cohesion compared with more affluent parts of the country.^17,18 Having less income might mean living in an area with no nearby shops selling fresh food, not having money for a car or public transport to access them, and working long hours or multiple jobs with less time to shop further from home or to prepare and cook meals.

Systematically considering the enabling and constraining factors that each building block contributes can help to identify gaps in prevention strategies (Fig 1). Interventions should aim to support desired behaviours by increasing enablers (eg swimming lessons) and decreasing constraints (eg living wage employment to afford activity). Interventions could also aim to alter the COM-B balance of competing behaviours (eg decreasing motivation for unhealthy foods by restricting advertising).^{6,8,11,15,16,20}

UK obesity prevention is not working

Since 1991, there have been 14 UK Government strategies containing 689 policies for obesity prevention, yet reductions in obesity prevalence or inequality have not been achieved.²⁰ Reviews of the Government's approach to obesity prevention found obesity strategies consistently frame behaviour change as choice driven, failing to comprehensively address the underlying drivers of obesity or inequalities. Downstream policies requiring high agency (ie a lot of personal resource is needed to benefit) predominated and were usually aimed at increasing motivation or capability by providing information. By contrast, structural policies and low-agency interventions, where people can benefit without needing to dramatically change their day-to-day behaviours, have been underutilised.^20,21

Information-based policies have included guidance, standards and professional development policies to build capability in the NHS, schools and the public sector.²⁰ Population-level policies provided information via campaigns and regulation, such as the ‘Better Health’ campaign for diet, the ‘Moving Healthcare Professionals’ campaign for activity, voluntary front-of-pack nutrition labelling (introduced in 2007) and mandatory regulation requiring large business to provide calorie-labelling on menus (introduced in 2022).²¹ High-agency interventions such as these generally benefit individuals who have sufficient resources to access, understand and act on the information provided, all of which are socially economically stratified and, therefore, have the potential to increase inequalities.²² Although obesity was recently announced as one of four healthcare missions that will take a ‘vaccine-taskforce style approach’ to trial new medicines,²³ this demonstrates a continuing policy preference for high-agency, targeted and individual-based approaches at the expense of the cross-Government strategic approach needed.

Altering obesogenic environments with low-agency interventions can be more effective and equitable because these interventions do not rely on individuals' resources to provide benefits.^20–22,24 The UK Soft Drinks Industry Levy (SDIL) 2018, a mandatory industry levy on high-sugar beverages, decreased the proportion of high-sugar drinks from 49% to 15% by incentivising manufacturer reformulation, and recent data suggest it has already had a direct impact on childhood obesity.²⁴ Food reformulation and fiscal policies are recommended by the World Health Organization (WHO) as cost-effective and progressive interventions. Fiscal policies can influence reformulation and consumption, and reformulation policies can improve population nutrient intakes and health outcomes, with mandatory approaches being shown to be more effective compared with voluntary policies.^25,26 Despite the evidence of their effectiveness and public support of commercial regulation,²⁷ UK governments (regardless of political party) have been timorous in combating the commercial determinants of obesity. Policies tackling this building block of health have been underutilised and lenient; only 19% of UK obesity policies since 1991 were structural and, of these, 64% were voluntary or relied on self-regulation.²⁰ Recent proposals for stricter rules have been delayed or discarded; restriction of high-fat-salt-sugar (HFSS) food advertising to children and promotional offers in shops has been delayed until 2024,²⁸ and the proposed inclusion of sugary milk drinks in the SDIL and ban of energy drink sales to under-16s have not been implemented.²¹

When risk factors for disease are major profit drivers for industry, commercial actors can pose significant barriers to improving public health,²⁹ using a range of strategies to undermine or avoid public health policies, such as lobbying, distorting evidence, promoting voluntary and often ineffective self-regulation, and shaping the policy narrative by shifting the focus from health to consumer choice.^16,30 Improving our home, work and community environments by challenging harmful industries is possible. Clinicians' raised awareness on smoking harms, and shifting the narrative led to the introduction of successive population-level policies to reduce smoking rates (such as a ban on smoking in public places, and raising the price of tobacco), and regulation that countered corporate influence on motivation to smoke (such as restricting advertising and introducing plain packaging).³¹ Clinicians now have the same opportunity to help create healthier diets through highlighting the role of commercial determinants in shaping the food we eat, and how they can be shaped through regulation to help support individuals, families and communities live healthier lives.

Clinicians as change agents

Clinicians are a trusted voice at all levels of the health and care system, with skills in leadership, advocacy, partnership working, service delivery, and strategic transformation. Therefore, clinicians are ideal champions for delivering a prevention approach that reduces obesity-related harm through not only patient-facing clinical work, but also tackling the building blocks of health. Clinicians can choose to instigate, advocate or drive forward this approach with patients, within their organisation, through place-based partnerships and integrated care systems, national policymaking, with the media or in the voting booth. Box 2 sets out a summary of recommendations for clinicians.

Misunderstanding the significant influence of the building blocks of health on behaviour fuels obesity prejudice and derails conversations on effective prevention.^13,15 Clinicians can facilitate change by promoting an understanding with colleagues, patients and the public of both the environmental and individual factors that cause obesity. This can help to combat weight-related stigma and shift the dominant narrative from individual blame to collective responsibility so that population interventions are viewed not only as permissible, but also essential.¹⁵

Healthcare organisations should be the healthiest settings in our communities, exemplifying how employers can create healthy-weight work environments.³² Yet, many NHS organisations fall short on their responsibilities to staff, visitors and patients. Clinicians can foster an organisational culture that supports obesity prevention; training staff to have healthy-weight conversations,³ providing time for physical activity and encouraging junior colleagues to undertake obesity-related improvement projects. Clinicians can also work with trusts to improve healthcare environments, empowered by the recommendations made to senior managers and budget holders in National Institute for Health and Care Excellence (NICE) guidelines (CG43)³ and quality standards (QS111),⁴ which include the following:

• Ensuring healthy food/drink choices are available (including in vending machines) and promoted (eg through advertising, pricing or displaying in prominent positions) and that menus detail nutritional content.

• Promoting movement through policies, facilities and prompts (eg by providing showers and secure cycle parking, or using spatial design to encourage stair use).

• Supporting the implementation of workplace programmes to prevent and manage obesity.

As anchor institutions, NHS organisations can leverage their significant resources to support healthy-weight communities through actions such as providing local employment (with conditions and pay that enable health-weight behaviours), maximising use of natural and built estates to provide communities with spaces for physical activity, and securing healthy, local and sustainable food.¹³

Preventing obesity requires a multi-agency community-wide approach (NICE PH42),³² but this does not mean that all organisations should attempt to address all drivers of obesity. When partners work with an agreed narrative and strategic framework, each is able to focus on areas where they can have the greatest impact, knowing their actions coherently and interdependently contribute toward the shared goal. Clinicians are instrumental in promoting this multi-agency alignment because they are the interface between patients, place-based partnerships and integrated care systems (ICSs) (see Box 3). Using this privileged position of multiple perspectives, clinicians can ensure that frontline patient needs are used to inform the strategic priorities set by the ICS and the interventions designed by place-based partnerships.

NICE guidance on behaviour change (PH49) recommends all health staff use very brief interventions that meet individual needs and apply evidence-based principles.³³ Clinicians who identify patients with overweight or obesity should provide information on local weight management programmes or, if relevant, the ‘Healthier You National Diabetes Prevention Programme’, which has evidence for population-level weight loss.^4,13 Clinicians should explore barriers to lifestyle change, as recommended by NICE CG43.³ Drawing on the approach described in this article might highlight barriers in COM-B behaviour components, such as cost, time, safety concerns, family and community views, disabilities and self-esteem.³ Social prescribing could ameliorate some of these barriers,¹³ whereas others will lack locally available solutions. This is a crucial insight that clinicians must bring from the clinic to place-based partnerships and ICS, where they can engage with communities and system partners (eg local government) to co-design local culturally competent solutions that build capacity, provide opportunities and support motivation for healthy-weight behaviours.^5,32,34 Clinicians can use approaches outlined in the Health Foundation's ‘Framework for NHS action on the social determinants’ to help improve this alignment of patients, needs and resources.³⁴

According to NHS England the purpose of an ICS is to ‘improve population health’, ‘tackle inequalities’, and help the NHS ‘support broader social and economic development’.³⁵ Obesity prevention will drive progress across all three objectives. As ICSs mature, there is a window of opportunity to modify system incentives so that adequate resources are directed at both prevention and treatment.¹³ Integrated-care and place-based partnerships can use the approach discussed in this article and summarised in Fig 1 to reveal local drivers of obesity and the local policies needed to tackle them, and can act as a tool for communicating how collective action can lead to collective transformation.

Conflicts of interests

ERH is a member of the Faculty of Public Health. AB is a co-applicant on the National Institute for Health Research grant number 16/130/01, evaluating the impact of the UK Soft Drink Industry Levy, and is a member of the Faculty of Public Health and an associate member of the Association of Directors of Public Health. Both organisations have policy positions on the role of national government in the prevention of obesity.