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PRP (39-01-03) Effects of advertising and in-store promotions on child pestering for unhealthy foods


Published: 14 May 2024

Version: 1.0 - May 2024

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Timetable and Budget

Deadline for Stage 1 Applications 18 June 2024, 1pm
Notification of outcome of Stage 1 Applications September 2024
Deadline for Stage 2 Applications 22 October 2024, 1pm
Notification of outcome of Stage 2 Applications February-March 2025
Earliest potential project start June 2025
Project duration 24 months 
Budget £450,000


The National Institute for Health and Care Research (NIHR) Policy Research Programme (PRP) invites applications for a single research project to evaluate the influence that children have over the purchasing patterns of their parents when shopping for food. This is in the context of legislation to restrict the promotion of food high in fat, sugar or salt (HFSS) online and in food stores.


Obesity is one of the biggest health problems this country faces. Around two-thirds of adults are above a healthy weight [1], and over a fifth of children in England are living with overweight or obesity by the time they start primary school aged 5, and this rises to over one third by the time they leave aged 11 [2]. Regular over consumption of food and drink high in calories, sugar and fat (‘HFSS’) can lead to weight gain and, over time, obesity, which in turn has a significant impact on health and well being and increases the risk of obesity-related diseases.

‘Pester power’ describes the influence that children try to exert on their parents to make purchases they may not otherwise have made. A large proportion of these purchases is known to be of unhealthy food products which contribute to childhood obesity. Pestering is often triggered on shopping trips when children see products they know from advertising or are influenced by other features of product marketing including its location, signposting and packaging. For younger children (generally children 10 and under) who do not have access to their own means of purchasing foods, a key mechanism that links their exposure to advertising or promotions of unhealthy foods with consumption of such foods is pestering [3]. This mechanism was recognised in the Impact Assessment for the Advertising Regulations [4] but no evidence was available to quantify its scale.

The Government has recognised the need to support parents experiencing pestering in Childhood Obesity: a Plan for Action Chapter 2 [5], which commits to acting to protect parents from these pressures by restricting advertising of HFSS foods on TV and online and their promotion in key locations in food stores. Tackling Obesity: Empowering Adults and Children to Lead Healthier Lives [6] also addresses ‘pester power’ in relation to proposals to restrict in-store promotions of HFSS foods: ‘We know that people want more choice on offers that support a healthy lifestyle and that high fat, salt and sugar (HFSS) products displayed prominently at shopping tills or on the end of aisles tempt us to add extra items to our baskets and ‘pester power’ from children puts pressure on parents to purchase unhealthy items at the shopping till.’

Regulations restricting the promotion of HFSS products by location in food stores came into force on 1 October 2022. These regulations target only key locations (checkouts, store entrances and end of aisles) and retailers and manufacturers may have adopted alternative ways to use location to promote HFSS products. We are keen to identify what features of the in-store environment continue to trigger pestering and quantify the impact of this.

New regulations restricting promotions of HFSS products by volume price in food stores and restricting their advertising on TV and online will come into force on 1 October 2025. A Post Implementation Review is required for each of these policies which evaluates their impact and assesses whether the regulations should be retained within 5 years of their implementation. Pestering was recognised in the Advertising Impact Assessment [4] as one of the main mechanisms through which advertising impacted on children’s consumption of less healthy foods and drinks and was noted by the Regulatory Policy Committee as an important evidence gap.

Regulatory policies require us to undertake Post Implementation Reviews [7] to assess whether policies are meeting their objectives and should be retained, amended or dropped. The findings from this research will contribute primarily to the Post Implementation Review of the Advertising regulations.

If timing allows the collection of data prior to the introduction of the advertising regulations, this research will provide a baseline for assessing the extent to which purchasing of HFSS products is influenced by pestering triggered by advertising. A second phase of research will be commissioned at a later date post-implementation to quantify change since the introduction of these regulations.

This research will also contribute to the Post Implementation Review of the Location Promotions regulations, due in 2027, as it will help us identify and quantify features of the in-store promotional landscape that continue to trigger pestering. We hope this research will identify pestering triggered by:

  • Breaches of the current location promotion regulations
  • Non-regulated forms of location promotions
  • Other aspects of product placement and marketing (e.g. low location on shelving, use of bright colours on packaging etc) that appeal to children.

Research Priorities

We would like the research to:

  • Assess the scale, nature and experience of pestering for HFSS food and drink products, including how pestering varies by circumstances and demographic groups;
  • Explore specific experiences of pestering and identify the triggers for pestering in order to produce robust estimates of the impact of pestering triggered by advertising and in-store promotions on purchasing of HFSS foods.

The scale, nature and experience of pestering for HFSS food and drink products

Up to date research is needed to quantify the scale, nature and experience of child pestering for HFSS food and drink products. We are interested in parents’ experiences of both in-store pestering and behaviours that influence parents to purchase HFSS products that occur separately from actual shopping trips. We would like to know:

  • What proportion of parents experience attempts by their children to influence the food that they buy when doing their main supermarket shop?
  • How does the experience of pestering differ by socio-economic characteristics?
  • How frequently does pestering occur?
  • In what circumstances and types of shop (e.g. during main shops, top-up shops, convenience stores etc) does pestering occur?
  • How many times per shopping trip do children pester for a food product?
  • What products are pestered for?
  • How do parents respond to these attempts? Which products do they agree/refuse to buy and why/why not?
  • Parents’ understanding of what triggers requests including whether requests are associated with exposure to advertising, in-store promotional strategies or other factors;
  • What do parents do to avoid pestering?
  • Parents’ views on what else stores could do to make it easier for them to shop more healthily.

We are also keen to understand more about the role played by advertising and other forms of marketing of HFSS products on shaping child requests for HFSS food products that can result in children seeking to influence what parents buy even when they are not present during shopping trips and how extensively this might influence parental purchasing of HFSS foods. These behaviours may take different forms such as complaining about parents’ shopping choices and fussiness or refusing to eat products that are not preferred.

A mix of both quantitative and qualitative research may be required.

Robust evidence on triggers for pestering for HFSS food and drink products when shopping with children

As well as providing evidence on parents’ general experiences of pestering, we are keen for this research to collect data on specific examples of pestering to explore its triggers and how these may relate to advertising and in-store promotions. This data collection should support a robust estimate of the impact that pestering has on the purchasing of HFSS foods in general as well as identifying the specific impacts of advertising and in-store promotions (including those in-scope of our regulations and those that are not).

In relation to specific shopping trips where incidents of pestering for food products were experienced, we would like to know:

  • What food/drink product(s) was/were pestered for;
  • The HFSS status of the products and whether they were in-scope of the advertising and location promotion regulations*;
  • Where the product(s) was/were located and whether they were subject to any in-store promotional tactics;
  • Whether the product(s) was/were purchased;
  • What triggered the pestering, taking into account both parent and child views on the desired products they wanted their parents to buy and the role played by:
    1. advertising;
    2. in-store promotional practices.

*Products in scope will be those that fall into one of the restricted categories [8] as well as having a score of 4 or more using the Nutrient Profile Model for foods and 1 or more for drinks [9].

Information collected could then be used to produce an estimate of the contribution of pestering in general and pestering arising from specific triggers to family purchasing of HFSS foods in terms of:

  • the number and type of HFSS products purchased, looking at what food categories pestered for products are from;
  • the total calorie contribution of HFSS foods purchased as a result of pestering;
  • the additional volumes of sugar, fat and salt purchased as a result of HFSS foods purchased as a result of pestering.

For this aspect of the research we would welcome proposals for methodologies that seek to overcome the challenges for research participants in recalling and reporting the details of events that occur in stressful situations as well as the differing understandings that parents and children may have about what triggered their pestering for specific products, including the use of innovative approaches to recruitment into the study.

Assessing the impact of the Advertising and Location Promotions Regulations

In order to assess the full impact of the promotions and advertising regulations on children’s diets, we would benefit from being able to quantify how the mechanism of pestering impacts on parent purchasing of HFSS foods. Ideally we would want to adopt a ‘before and after’ approach to data collection on pestering, to understand, as well as quantify, any change in its incidence and triggers as well as the types of products pestered for resulting from the introduction of the Advertising restrictions. If time allows, therefore, data collection would ideally be carried out before the advertising regulations are introduced in October 2025 with a second post-implementation phase commissioned at a later date. If this cannot be achieved, the research as a single phase will still be useful to assess the adequacy of the policy that has been implemented.

The Locations Promotions regulations have already been introduced and we will not be in a position to compare the pre- and post-implementation impacts of this policy on pestering. However, the Post Implementation Review for the Locations Promotions regulations, which came into force in October 2022, would also benefit from understanding the extent to which pestering triggered by in-store marketing practices has persisted and what practices are supporting it.

Areas out of scope for this programme of work

Full evaluation of either the advertising or promotions restrictions is not within the scope of this research.


Eligibility rules for the NIHR Policy Research Programme are explained in the Standard Information for Applicants and these apply to all calls unless otherwise stated in the individual research specification.

Expertise required

Food systems, food environments, food marketing, policy evaluation, in-store research.


Applicants are asked to consider the timing and nature of deliverables in their proposals. Policymakers will need research evidence to meet key policy decisions and timescales, so resource needs to be flexible to meet these needs. A meeting to discuss policy needs with DHSC officials will be convened as a matter of priority following contracting. 

Budget and duration

The maximum budget available for this call is £450,000. We expect the research to complete within 24 months.
Costings can include up to 100% full economic costing (FEC) but should exclude output VAT. Applicants are advised that value for money is one of the key criteria that peer reviewers and commissioning committee members will assess applications against.

Management arrangements

A research advisory group including, but not limited to, representatives of DHSC, other relevant stakeholders, and the successful applicants for the research should be established. The advisory group will provide guidance, meeting regularly over the lifetime of the research. The successful applicants should be prepared to review research objectives with the advisory group, and to share emerging findings on an ongoing basis. They will be expected to:

  • Provide regular feedback on progress
  • Produce timely reports to the advisory group
  • Produce a final report for sign off

Research contractors will be expected to work with nominated officials in DHSC, its partners and the NIHR. Key documents including, for example, research protocols, research instruments, reports and publications must be provided to DHSC in draft form allowing sufficient time for review.

Guidance on Health and Care Inequalities and associated data collection within NIHR PRP Research

Health and care Inequalities is a high priority area within the Department of Health and Social Care and the NIHR and is often present in a majority of funded projects. We are now assessing all NIHR research proposals in relation to health inequalities. We ask that you please clearly identify in the research plan section of the application whether your application has an inequalities component or theme as well as how this research hopes to impact inequalities or not. Please also detail the core set of inequality breakdown data that will be collected, if applicable. More information on this request can be found in the Standard information for applicants.

Improving Data Access Pilot

The NIHR are working together with the Data Access & Partnerships Team in NHS England (NHSE) to better align NHSE requirements for data access with NIHR commissioning processes.

This funding call will include a pilot to support researchers in making data access requests by identifying any potential issues and resource impact earlier in the process. If your research will require access to NHSE data, please find further details of the pilot on the Data Access Pilot Guidance Webpage.

References and key documents