Wine glass size and wine sales: A replication study in two bars

Objective. Wine glass size may influence perceived volume and subsequently purchasing and consumption. Using a larger glass to serve the same portions of wine was found to increase wine sales by 9.4% (95% CI: 1.9, 17.5) in a recent study conducted in one bar. The current study aimed to replicate this previous work in two other bars using a wider range of glass sizes. To match the previous study, a repeated multiple treatment reversal design, during which wine was served in glasses of the same design but different sizes, was used. The study was conducted in two bars in Cambridge, England, using glass sizes of 300ml, 370ml, 510ml (Bar 1) and 300ml and 510ml (Bar 2). Customers purchased their choice of a 750ml bottle, or standard UK measures of 125ml, 175ml or 250ml of wine, each of which was served with the same glass. Results. Bar 1: Daily wine volume purchased was 10.5% (95% CI: 1.0, 20.9) higher when sold in 510ml compared to 370ml glasses; but sales were not significantly higher with 370ml vs. 300ml glasses (6.5%, 95% CI: -5.2, 19.6). Bar 2: findings were inconclusive as to whether daily wine purchased differed when using 510ml vs. 300ml glasses (-1.1%, 95% CI: -12.6, 11.9). These results provide a partial replication of previous work showing that introducing larger glasses (without manipulating portion size) increases purchasing. Understanding the mechanisms by which wine glass size influences consumption may elucidate when the effect can be expected and when not.The research reported in this publication was funded by the Department of Health Policy Research Programme (http://prp.dh.gov.uk/) (Policy Research Unit in Behaviour and Health [PR-UN-0409-10109])

Explaining the effect on food selection of altering availability: two experimental studies on the role of relative preferences

Background: Increasing the availability of healthier or plant-based foods increases their selection. The current studies aimed to examine the extent to which relative preferences account for food selections following availability interventions. In particular, (a) whether increasing the availability of lower-energy options increases the likelihood that individuals’ highest-ranked option is lower-energy, and (b) the extent to which selections reflect individuals’ highest-ranked option from the available range. Methods: UK adults (Study 1: n=1976; Study 2: n=1078) took part in within-subjects online studies. In both studies, the order of preference between food options was established by participants choosing the option that they would prefer “to eat right now” from every possible pairing within a pool of eight options. Then, participants were shown either predominantly higher-energy options (three higher- and one lower-energy) or predominantly lower-energy options (vice versa), presented in a random order. Results: When predominantly lower-energy options were presented, the odds of the highest-ranked option being a lower-energy option increased ten-fold (Study 1: odds ratio: 10.1; 95%CI: 8.9,11.4; Study 2: odds ratio: 10.4; 95%CI: 7.4,14.7), compared to when predominantly higher-energy options were available. In both studies, around 90% of selections reflected the highest-ranked option in the range offered in the studied availability conditions (range 88-92%). Conclusions: These studies suggest that increased availability of lower-energy options increases the likelihood of an individual’s highest-ranked option being lower-energy, and that the highest-ranked option has the greatest likelihood of selection. As such, preferences may be a key contributor to the effects of altering availability on food selections.</p

Perceptions of social norms around healthy and environmentally-friendly food choices: linking the role of referent groups to behavior

Referent groups can moderate the perception of social norms and individuals’ likelihood to model these norms in food choice contexts, including vegetable intake and reduced meat consumption. The present study investigated whether having a close vs. a distant social group as the referent changed perceptions of social norms around making healthy and eco-friendly food choices. It also assessed whether these changes were associated with a difference in the health and environmental impacts of food choice in a virtual grocery shopping task. A nationally representative sample of UK adults (N = 2,488) reported their perceptions of making healthy and eco-friendly food choices being the norm among people they share meals with (close referent group) and most people in the UK (distant referent group). The former was more commonly perceived to be making both healthy (Z = −12.0, p  0.05, 95% CIs: −1.12, 0.25) and health (β = −0.06, p > 0.05, 95% CIs: −0.37, 0.25) impacts. Framing social norms around making healthy and eco-friendly food choices to refer to a close referent group may change their perceptions and ability to encourage sustainable and healthy food purchasing

Is altering the availability of healthier vs. less-healthy options effective across socioeconomic groups? a mega-analysis

Background: Availability interventions have been hypothesised to make limited demands on conscious processes and, as a result, to be less likely to generate health inequalities than cognitively� oriented interventions. Here we synthesise existing evidence to examine whether the impact of altering the availability of healthier vs. less-healthy options differs by socioeconomic position. Methods: Individual-level data (21,360 observations from 7,375 participants) from six studies (conducted online (n=4) and in laboratories (n=2)) were pooled for mega-analysis. Multilevel logistic regressions analysed the impact of altering the availability of healthier options on selection of a healthier (rather than a less-healthy) option by socioeconomic position, assessed by (a) education and (b) income. Results: Participants had over threefold higher odds of selecting a healthier option when the available range was predominantly healthier compared to selections when the range offered was predominantly less-healthy (odds ratio (OR): 3.8; 95%CIs: 3.5, 4.1). Less educated participants were less likely to select healthier options in each availability condition (ORs: 0.75-0.85; all p Conclusion: Increasing the proportion of healthier options available increases the selection of healthier options across socioeconomic positions. Availability interventions may have a slightly larger beneficial effect on those with the highest levels of education in settings when healthier options predominate.</p