A nudge in the right direction: The efficacy of visual nudges for encouraging healthier dietary behaviours

Author: Enola Kay

  • Thesis download: available for open access on 28 May 2025.

Kay, Enola, 2024 A nudge in the right direction: The efficacy of visual nudges for encouraging healthier dietary behaviours, Flinders University, College of Education, Psychology and Social Work

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The contemporary food landscape heavily promotes the consumption of unhealthy, ultra-processed foods and beverages. Sugary drinks, being the second largest contributor to this landscape and the primary source of excess sugar consumption in Australia, particularly among young adults, warrants specific focus. The overconsumption of such unhealthy products can lead to a range of physical and mental health issues such as cardiovascular disease, cancer, anxiety, and depression. As such, effective strategies are needed for promoting healthier diets.

Traditional methods for encouraging healthier diets, like sugar taxes or health campaigns, have shown limited success in achieving long-lasting, widespread change. This could, in part, be due to their failure to acknowledge the importance of consumer autonomy and the automatic nature of dietary behaviours and decisions. In contrast, nudging is an implicit approach that recognises and leverages automatic decision-making processes while preserving autonomy. Nudges guide people towards desired (e.g., healthier) behaviours by making them more prominent or the simplest/default option. Given the highly visual nature of our food and beverage environment, visual nudges offer potential for influencing consumption behaviours.

This thesis investigates the effectiveness of implicit nudging interventions in promoting healthier choices, with a particular focus on visual nudges and beverage choices. It comprises four empirical studies and a systematic review and meta-analysis.

Studies 1 and 2 (Chapter 2) examined subtle beverage primes for nudging drink choices from a food and beverage environment akin to a vending machine. While extremely subtle primes had no influence (Study 1), clearer but still subtle primes nudged drink choices (Study 2). However, the primes did not affect the healthiness of choices, suggesting that a more obvious approach is needed to promote healthier choices.

Studies 3 and 4 (Chapter 3), assessed a more overt approach to nudging drink choices, where the primes were the primary focus of a vending machine advertising poster. The healthy (water) prime successfully encouraged water choices in a beverage-only vending machine (Study 3) but had less impact when food options were added (Study 4).

Findings from Studies 1-4 indicated potential variations in the effectiveness of different nudges in different contexts. To provide an overview of the literature, Chapter 4 presented a systematic review and meta-analysis (Study 5) examining the effectiveness of various food- and body-related visual nudges for influencing food and beverage choices and identified potential mechanisms and moderators of nudge success. Results supported the efficacy of visual nudges for influencing food and beverage choices but demonstrated the need for further research to elucidate why, when, and for whom specific nudges are most effective.

Overall, the present thesis demonstrates the potential of visual nudging interventions for promoting healthier dietary behaviours, with important implications for public health interventions aimed at improving population health. However, findings underscored the importance of tailoring nudging strategies for specific settings, and the need for further research to better enable this process. Insights from the present thesis provide valuable knowledge for policymakers, educational institutions, and food vendors interested in fostering healthier eating habits, especially when combined with future research elucidating underlying mechanisms and moderators.

Keywords: nudge, nudging, priming, cueing, drink choices, food choices, healthy diets, sugar-sweetened beverages, vending machines

Subject: Psychology thesis

Thesis type: Doctor of Philosophy
Completed: 2024
School: College of Education, Psychology and Social Work
Supervisor: Eva Kemps