Identifying intervention content to support reductions in parental provision of unhealthy foods to their three to seven-year-old children

Author: Brittany Johnson

Johnson, Brittany, 2020 Identifying intervention content to support reductions in parental provision of unhealthy foods to their three to seven-year-old children, Flinders University, College of Nursing and Health Sciences

Terms of Use: This electronic version is (or will be) made publicly available by Flinders University in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. You may use this material for uses permitted under the Copyright Act 1968. If you are the owner of any included third party copyright material and/or you believe that any material has been made available without permission of the copyright owner please contact with the details.


Australian children's unhealthy food intake is excessive, with three to seven-year-olds currently consuming up to eight times the dietary guideline recommendations. Unhealthy food intake is influenced by numerous factors across the socio-ecological framework. Parents are an ideal target population to create meaningful reductions in children's unhealthy food intake. Interventions to date have not reversed the trend in children’s excess unhealthy food consumption. New interventions are needed using a rigorous approach to intervention design to enhance intervention effectiveness. This thesis aimed to design theoretically grounded, evidence-informed intervention content to support parents to reduce unhealthy food provision to their three to seven-year-old children. Intervention design followed best-practice processes using the Behaviour Change Wheel, including performing a behavioural analysis based on the Capability, Opportunity, Motivation and Behaviour (COM-B) model.

Four studies were undertaken to address the overall thesis aim. The first three studies sought to generate new knowledge to fill gaps in the current evidence base. The final study directly addressed the overall thesis aim through best-practice intervention design. Study 1 (Chapter 3) used a cross-sectional design to measure parent-reported motivational constructs, analysed by structural equation modelling, to understand parents’ reflective motivation. Study 2 (Chapter 4) used a discrete choice experiment to understand the relative importance of physical and social opportunity on parents’ snack provision decision-making. Study 3 (Chapter 5) involved undertaking a systematic review and deconstructing parent-focussed interventions into their behaviour change components to identify novel approaches to behaviour change. Study 4 (Chapter 6) followed the Behaviour Change Wheel process to identify intervention content options.

Findings from parents self-reported motivational constructs in Study 1 (n=495), identified self-efficacy, intention and planning were the constructs of most importance. Study 2, the discrete choice experiment with parents (n=225), found home food availability, child resistance and support from co-parents were of greatest relative importance in parents’ snack provision to their children. The systematic review, Study 3, found interventions to date have resulted in small to moderate reductions in children’s unhealthy food intake. Deconstructing interventions revealed there is untapped potential in several behaviour change components to design theoretically informed parent-focussed interventions to reduce unhealthy foods. In Study 4, theoretically grounded, evidence-informed intervention strategies were designed to be implemented across socio-ecological levels and prioritised to target purchasing of unhealthy sweet and savoury snack foods for the home. Intervention content seeks to address the gaps identified in the behavioural analysis to increase aspects of parents’ psychological capability, physical and social opportunity, and reflective and automatic motivation.

This thesis contributes new knowledge to address children’s unhealthy food intake, as well as novel methodological applications of behaviour change theory and discrete choice experiments to the field of behavioural nutrition. This PhD project provides a comprehensive approach to designing intervention content. Resulting intervention content provides a suite of intervention strategies that could be implemented in multiple environmental settings to support parents to reduce unhealthy food provision, whilst avoiding widening socio-economic inequalities. Future research can test outputs from this thesis in interventions to create meaningful reductions in young children’s unhealthy food intake.

Keywords: unhealthy foods, parents, intervention design, children's nutrition, behaviour change

Subject: Nutrition and Dietetics thesis

Thesis type: Doctor of Philosophy
Completed: 2020
School: College of Nursing and Health Sciences
Supervisor: Professor Rebecca Golley