Investigating the impact of food vouchers on diet composition and the prevention of childhood obesity

Childhood obesity is increasing in the UK, and children from disadvantaged backgrounds are more likely to live with obesity. Obesity in childhood is linked to obesity in adulthood and poor health outcomes. It is therefore vital that we work to prevent and reduce inequalities in childhood obesity. We know that children from disadvantaged backgrounds are more likely to have poor diets, and children who have poor diets are more likely to be obese. Therefore, improving diet quality of young families may contribute to preventing the development of childhood obesity.

Healthy Start is a scheme in England that aims to improve diet quality by providing vouchers to spend on milk, fruit and vegetables to disadvantaged families. However, the voucher value is modest and has not changed for a decade, despite increasing food prices. The scheme needs assessing to consider how it can best support families, as uptake among eligible families is very low, at 54% nationally.
Health visitors support young families, and give extra support to those with increased needs, including those from deprived groups. This provides a unique opportunity to support young families who are at risk of childhood obesity and eligible for Healthy Start. The aim of this research is to understand if voucher schemes can have a positive effect on diet quality of disadvantaged families.

This research will contain several elements, including reviewing the literature for evidence on the effectiveness of voucher schemes, speaking to families and health visitors, collecting diet and shopping information from families, and modelling the best approach to a modified Healthy Start scheme.

In phase one, a systematic review will be completed to collect evidence from the scientific literature on the effect of voucher-based schemes on diet quality and childhood obesity in children.
Phase two includes collection of dietary information and speaking to parents receiving health visiting services and health visitors about food buying decisions, healthy diets and Healthy Start.
In phase three, information from phases one and two will inform a statistical model that can be used to predict what people receiving the voucher would do if the vouchers were changed in some way. This will use Agent Based Modelling (ABM), a method that involves programming 'agents' (virtual people) to follow certain rules and interact with each other, allowing researchers to predict the impact of a change to Healthy Start. For example, if Healthy Start vouchers were increased to £5 (from the current value of £3.10) for families at risk of childhood obesity, what affect would this have on the food that people buy? The data gathered from phases one and two will be used to build the model accurately, thus ensuring that the model reflects real life as closely as possible.

Patient and public involvement (PPI) work has already shaped this application and will continue to support the ongoing project, through outreach work aiming to increase diversity of contributors, and PPI contributors' involvement in a steering group. The results from this study will be communicated to participants using a summary sheet, and PPI contributors will be supported to disseminate the information to local communities. The findings will be written up for publication and submitted to conferences and peer reviewed journals in order to share with academic audiences.

This study will inform policy, practice and further research by providing evidence on how best to modify Healthy Start to improve diet quality and provide support to disadvantaged families at risk of childhood obesity. The next step would be to trial the most successful modelled changes to Healthy Start in local populations. If successful, this has the potential to improve diet quality and reduce risk of childhood obesity in vulnerable families. This in turn may lead policy change contributing to reduced health inequality for children across England.

Childhood obesity in the UK is increasing, and children from deprived areas are twice as likely to be obese as those from more affluent areas. Poor diets are linked with both deprivation and increased risk of childhood obesity. Improving diet quality in deprived groups, particularly those at high risk, may reduce the risk of childhood obesity and reduce health inequalities. The UK government's Healthy Start scheme aims to improve diet quality among low-income families by providing vouchers to spend on milk, fruit and vegetables. However, the scheme has poor uptake and unknown benefit.

This research aims to understand how a food voucher system can best operate to improve dietary quality and reduce inequalities, and to model potential scenarios for its application to achieve maximum effectiveness for the prevention of childhood obesity.

The research has three planned phases:

Phase one
A systematic review of the impact of voucher based interventions on diet quality and obesity in pregnant women and young children.

Phase two
Food diaries and food purchasing information will be collected from 200 families, in an extended health visiting service for vulnerable families. Many of these families will be from disadvantaged groups, and may be at risk of childhood obesity. In-depth interviews will be carried out with 20 parents and focus groups with 15 health visitors, considering food purchasing, diet quality and barriers and enablers to Healthy Start.

Phase three
Data gathered in phases one and two and from the wider literature will be used to inform an Agent Based Modelling (ABM) model. This novel application of ABM will model changes in food purchasing behaviour and diet following changes to the Healthy Start scheme, such as increasing voucher value. This will provide evidence for a trial of changes to the scheme, and subsequently, national policy changes.

Overall, this project will help support evidence based policy decisions for young families.