Out-of-home food selection behaviour in the presence and absence of price-based incentives in a virtual food delivery app: a randomised controlled trial.

Policies restricting price-based incentives in the out-of-home (OOH) food sector could influence food-related behaviours and improve population diet. In the present study we assessed the impact of removing price-based incentives on consumer food selection through a virtual, hypothetical, OOH delivery platform. Participants ordered a hypothetical meal for their household using a virtual ordering platform which presented the menu of a popular UK pizza chain restaurant/takeaway outlet. Participants were randomly allocated to one of 5 experimental conditions: control (all price-based incentives present), price reductions removed (e.g., 25 % off when you spend £10), value pricing removed (product size increase for a disproportionately small price increase), bulk-buy reductions removed (meal deals at discounted prices), and all price-based incentives removed. We examined the impact of removing each of the price-based incentives individually and simultaneously on hypothetical food purchases (energy selected (kcal) and money spent). There was a main effect of price-based incentive experimental condition on energy selected (F(4, 1919) = 3.51, p = .007) and money spent (F(4,1919) = 163.48, p < .001) and there was no evidence that effects of removing price-based incentives differed by participant characteristics. Participants in the control condition had a significantly lower hypothetical spend than all other conditions. Kcal selected tended to be lower in the all price-based incentives removed condition compared to the control condition (-7 %) and other conditions (average -8 %), although only the difference between all price-based incentives removed and value pricing removed conditions reached pre-specified statistical significance (-364 kcal; p < .0125; d = 0.21). Bayes Factors indicated that for all other pairwise comparisons the data did not provide strong evidence to support either the presence or absence of an effect. Therefore, further research is necessary to assess the impact of removing price-based incentives in OOH food settings.