Food and drink high in fat, sugar and salt - out of home advertising restrictions: rapid evidence review

Introduction

Obesity is defined by the World Health Organisation (WHO) as a multifaceted, non-communicable disease associated with excess adiposity and subsequent poor health outcomes, including mortality, cardiovascular disease, diabetes, and some cancers. There is no one cause of obesity; rather, it can occur due to complex interactions between biological, commercial, social, and political factors ^[14].

Scotland has the highest levels of overweight and obesity in the UK, with around two thirds of Scottish adults (66%) currently living with overweight or obesity ^[15]. Overweight and obesity levels amongst children remain a concern, with 17% of Scottish children at risk of living with obesity in 2023, increasing from 14% since records began in 1998. In 2022, the annual cost of obesity in Scotland was estimated to be £5.3 billion, which is predicted to rise further^[16].

One factor influencing the high prevalence of overweight and obesity is diet. Scottish Health Survey (2022) data ^[17] confirms that Scotland has a poor diet and with too many calories being consumed. Scottish Dietary Goals^[18] have been missed since they were introduced in 1996^[19]. For example, children should consume five portions of fruit and vegetables per day, but only 21% of children aged 2 – 15 met this target in 2022^[20]. Therefore, finding new methods to improve diet and subsequently overweight and obesity is a significant public health priority in Scotland.

In 2018, the Scottish Government published a policy highlighting their vision to halve childhood obesity by 2030 through fostering healthy diet and regular physical activity^[21]. A Healthier Future: Scotland’s Diet and Healthy Weight Delivery Plan includes five key outcomes:

• “Children have the best start in life – they eat well and have a healthy weight”
• “The food environment supports healthier choices”
• “People have access to effective weight management services”
• “Leaders across all sectors promote healthy weight and diet”
• “Diet-related health inequalities are reduced”

However, it is increasingly difficult for many people to eat well and maintain a healthy diet and weight due to sedentary lifestyles and factors in the environment, such as exposure to advertising of food and/or drinks high in fat, sugar, and salt (HFSS), often referred to in the media as “junk food”^[22]. HFSS products are marketed using a range of media including broadcast television,^[23] promotions within stores and online,^[24] and via outdoor advertising such as billboards, posters, bus stops, kiosks, and phone boxes^[25]. Research shows that there is an association between exposure to HFSS advertising and consumption, with children particularly vulnerable to the effects of advertising^{[26] [27]}. Advertising of HFSS products therefore has a clear influence on children’s dietary intake and could be contributing to the high prevalence of overweight and obesity.

Current regulations

As part of the tackling obesity strategy^[28], from 2020, the UK government announced a 9.00pm watershed on TV and online advertising of HFSS products, prohibiting advertisements from being shown between the hours of 5.30am and 9.00pm. The new advertising restrictions were initially planned to take effect from 1 January 2023. However, implementation of the policy has now been delayed to 1 October 2025^[29]. The new policy tightens current regulations that prohibit advertising of HFSS products in programmes aimed at children and on children’s TV channels, which has been in place since 2007 ^[30].

Children are also exposed to HFSS promotions online and in-store. Price promotions, such as “buy one get one free” influence people’s buying behaviour and consequently the amount of food purchased and consumed^{[31] [32]}. To further reduce HFSS consumption, the UK Government has passed regulations to restrict promotions of HFSS products by volume price and location in England, although only implemented location promotions to date^[33]. Key locations restricted are store entrances, end of aisles, checkouts, and equivalent locations online. The restrictions of HFSS products by location came into effect on 1^st October 2022, and restrictions by volume price are due to be implemented on 1^st October 2025.

Out of Home Advertising

Children and adults are also influenced by of out of home (OOH) advertising through a range of advertisements that can be seen in public places, for example, posters, screens, billboards, buses, taxis, banners, and phone kiosks^[34]. The content of advertising is guided by the Advertising Standards Authority (ASA), the leading independent regulator of advertising in the UK funded by advertisers. The ASA code prohibits advertisements that are misleading or cause harm and/or offence. In addition, there are guidelines around marketing aimed at children, political advertising, food and nutrition, gambling, alcohol, and tobacco.

The ASA states that HFSS products should not be placed close to areas in the UK where more than 25% of the audience are children aged under 16^[35] . Outdoor advertising is not considered to fall into this category as the audience is usually considered to be the general population, which is not, at the present time, considered to consist of more than 25% of under 16s. However, the ASA advises marketers to be aware of placing HFSS advertisements in locations close to schools, where there is a skewed distribution of under 16s. The ‘100 metre rule’ is already followed by many outdoor media owners when promoting age restricted products such as gambling, alcohol or e-cigarettes.

The ASA guidance around HFSS advertising is, to some extent, open to interpretation, and breaches of the rule have been reported^[36]. Furthermore, research shows that many children are still exposed to unhealthy advertising in other areas. For example, children from deprived areas view more HFSS advertising due to using public transport more frequently to travel to and from school^[37]. This contributes to diet-related health inequalities and suggests that stricter measures are required to prevent OOH advertising of HFSS products.

Policies that restrict OOH advertising of HFSS products have been implemented in some parts of the United Kingdom (UK). However, to date, we are not aware of any evidence review that has been conducted to gather information about policies that are currently in place around the UK.

Aims

The first aim of this review was to gather and synthesise the existing relevant evidence around OOH advertising restrictions of HFSS products in the UK to summarise the following:

• What we can reasonably say about the effectiveness of OOH advertising restrictions for HFSS products
• Evidence-based solutions to address advertising of HFSS products in Scotland
• Directions for future research

The second aim of this review was to inform policy discussions relating to Scotland’s diet and healthy weight delivery plan^[38].