Author: Indah Gynell
Gynell, Indah, 2022 Implicit interventions to promote healthier food choices from menus, Flinders University, College of Education, Psychology and Social Work
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Unhealthy diets and associated negative health outcomes (e.g., obesity, heart disease, some cancers) are problematic. Because of the limited long-term success of explicit healthy-eating interventions (e.g., weight-loss diets, sugar tax regulations), recent attempts to promote healthier eating have focused on implicit interventions, which are based upon the autonomy-preserving principles of nudging. However, research on implicit interventions, particularly in food menu contexts, is limited and inconclusive. This is particularly the case for placement interventions, which aim to increase healthier choices by positioning healthy foods in optimal locations. Therefore, this thesis aimed to investigate the effectiveness of implicit interventions, particularly placement interventions, to promote healthier food choices from menus.
The thesis consists of a systematic review and five empirical studies. The systematic review, which evaluated the literature on implicit healthy-eating interventions in food menus, found that placement and default interventions were consistently effective at promoting healthier eating. Priming/cueing, ratio and naming interventions also showed promise but require further research, while signage interventions were generally ineffective.
Studies 1 and 2 tested three variations of a healthy-eating placement intervention in two different settings. Specifically, presentation of healthy foods in the top, middle, and bottom sections of a physical (Study 1) and online (Study 2) snack menu were compared. The placement of healthy snacks made no difference to healthy choices from the physical menu. However, healthy snacks were chosen more from the top section, in comparison to the middle or bottom sections, of the online menu.
Studies 3-5 sought to further compare presentation of healthy foods in the top, middle, and bottom sections, using longer online menus offering mains, sides and desserts. This was examined for fast-food (Study 3), Chinese (Study 4), and mixed Australian (Study 5) cuisines. The number of healthy food choices from the fast-food and Chinese menus did not vary between conditions. However, participants made more healthy choices from the mixed Australian menu when healthy options were presented in either the top or bottom sections of the menu, rather than the middle.
Dietary restraint was measured in all five empirical studies to explore whether placement effects might be stronger for restrained than unrestrained eaters. However, dietary restraint had no effect on the efficacy of the interventions. Therefore, the observed positive placement effects in Studies 2 and 5 may occur regardless of dietary restraint.
Overall, the thesis contributes to our understanding of how best to promote healthier eating, broadly supporting the use of nudging and implicit interventions in menus. More specifically, the thesis provides good evidence that placing healthy foods in the top section of a menu can increase healthier choices from online snack menus, and that placing healthy foods in both the top and the bottom sections can increase healthier meal choices from longer online menus, depending on the type of cuisine. These findings give way to important practical applications for general public health improvements, which could eventually lead to reduced instances of diet-related illness. They also provide valuable insight for food businesses looking to promote healthier eating.
Keywords: Implicit interventions, Nudging, Food choices, Item Placement, Menus
Subject: Psychology thesis
Thesis type: Doctor of Philosophy
Completed: 2022
School: College of Education, Psychology and Social Work
Supervisor: Professor Eva Kemps