Examining the use of food cues: nudge based approaches to increase the purchase of vegetables among young adults in B.C.




Mistura, Matheus

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Vegetable intake is an important contributor to overall health, as vegetables are characteristically high in nutrient density and fibre and low in caloric density. In the student transition from high school to the university years vegetable consumption tends to deteriorate, potentially influencing both immediate and longer term health outcomes. Based on the recognition in behavioral economics that environmental factors can influence behavior, either explicity or implicitly, nudge interventions where environmental factors are manipulated to influence choice have emerged as potential contributors to public health behavior change goals. Evidence of their impact is mixed and the breadth of strategies and settings in which they are tested are limited. It was important to test nudge strategies with young-adults in real world cafeteria settings. The purpose of this quasi-experimental study was to evaluate the impact of a contextually feasible evidence-informed nudge intervention on food purchasing behavior in a University residence cafeteria. A priming nudge in the form of fresh vegetables offered at the steam/hot food table, combined with a salience nudge (signage) was tested. A single-case A-B-A-B design was adopted over 12 weeks in the fall term with 2 periods of baseline (A phase) and 2 periods of intervention (B phase). Staff portion servings were observed visually during the lunch and dinner service (4 hours/day total) and the proportion of hot table purchases with a vegetable serving added was the outcome variable. Visual inspection was used to evaluate the impact of the intervention and was supported by an analysis of: trends, measures of central tendency (mean, medians), overlap in data points, variability and latency. Wilcoxon Signed Ranks test was also used to determine if ranking of proportions was associated with phase. Visual inspection showed a positive change in trends when the Nudges were in place, followed by a change in direction when they were withdrawn, although these shifts were more apparent for females and during the first presentation of the nudges, The more indepth analysis showed lack of stability in the baseline, high variability in each phase and a high percentage of overlapping data. As a result of the high variability and lack of visible trend changes in the second A-B phase the visual inspection results should be reviewed with caution. A latency effect was also not readily apparent. Wilcoxon Signed Ranks test showed that proportions of vegetables served were not significantly associated with phase overall and for either females or males only. In this case, the nudge intervention did not impact the vegetable purchasing patterns of university students. Observations and staff anecdotes highlighted other environmental conditions like menu choices, staff encouragement, timing in the term and student finances that may also be influencing choices.This research adds to a very few number of interventions testing the application of nudge theory in a real world setting. More research in real world environments is needed.



behavioural economics, nudge theory, dual-process theory, vegetable purchase, young adults, university, food environment