Increasing the availability of lower-energy foods increases their selection. The current studies examine the extent to which this effect could be mediated by social norms – assessed by perceived popularity of foods – which may be implied by their relative availability. Study 1 (Online): 2340 UK adults estimated the perceived popularity of products. Participants were randomised to see photos of cafeteria shelves varying in the availability of lower-energy options ( 1 / 4 lower-energy; 1 / 2 lower-energy; 3 / 4 lower-energy) and fullness of shelves (fuller; emptier). Study 2 (Laboratory): 139 English adults were asked to select a snack. Participants were randomised to select from trays varying in the availability of the lower-energy option ( 1 / 3 lower-energy; 2 / 3 lower-energy) and fullness of tray (fuller; emptier). In Study 1, evidence for an interaction was found, such that when shelves were fuller, a higher proportion of lower-energy options led to greater perceived popularity of lower-energy products ( 1 / 4 lower-energy: 40.9% (95%CIs: 40.1,41.8); 3 / 4 lower-energy: 47.2% (46.3,48.0)), whereas when shelves were emptier, a higher proportion of lower-energy options led to lower perceived popularity ( 1 / 4 lower-energy: 48.4% (47.5,49.2); 3 / 4 lower-energy: 39.2% (38.3,40.0)). In Study 2, when the tray was fuller, participants were more likely – albeit non-significantly – to select a lower-energy snack when 2 / 3 of the available snacks were lower-energy (35.7% (18.5,52.9)) than when 1 / 3 were lower-energy (15.4% (4.2,26.5)). For emptier trays, lower-energy selections decreased as the relative availability of lower-energy snacks increased ( 1 / 3 lower-energy snacks: 36.0% (17.9,54.1); 2 / 3 lower-energy snacks: 27.8% (13.9,41.7)). These studies provide novel evidence that social norms may mediate the impact of availability on food selection. In addition, they suggest that the effect of availability may be moderated by display layout through its impact on perceived product popularity.

Background Overconsumption of energy from food is a major contributor to the high rates of overweight and obesity in many populations. There is growing evidence that interventions that target the food environment may be effective at reducing energy intake. The current study aimed to estimate the effect of decreasing the proportion of higher energy (kcal) foods, with and without reducing portion size, on energy purchased in worksite cafeterias. Methods and findings This stepped-wedge randomised controlled trial (RCT) evaluated 2 interventions: (i) availability: replacing higher energy products with lower energy products; and (ii) size: reducing the portion size of higher energy products. A total of 19 cafeterias were randomised to the order in which they introduced the 2 interventions. Availability was implemented first and maintained. Size was added to the availability intervention. Intervention categories included main meals, sides, cold drinks, snacks, and desserts. The study setting was worksite cafeterias located in distribution centres for a major United Kingdom supermarket and lasted for 25 weeks (May to November 2019). These cafeterias were used by 20,327 employees, mainly (96%) in manual occupations. The primary outcome was total energy (kcal) purchased from intervention categories per day. The secondary outcomes were energy (kcal) purchased from nonintervention categories per day, total energy purchased per day, and revenue. Regression models showed an overall reduction in energy purchased from intervention categories of −4.8% (95% CI −7.0% to −2.7%), p < 0.001 during the availability intervention period and a reduction of −11.5% (95% CI −13.7% to −9.3%), p < 0.001 during the availability plus size intervention period, relative to the baseline. There was a reduction in energy purchased of −6.6% (95% CI −7.9% to −5.4%), p < 0.001 during the availability plus size period, relative to availability alone. Study limitations include using energy purchased as the primary outcome (and not energy consumed) and the availability only of transaction-level sales data per site (and not individual-level data). Conclusions Decreasing the proportion of higher energy foods in cafeterias reduced the energy purchased. Decreasing portion sizes reduced this further. These interventions, particularly in combination, may be effective as part of broader strategies to reduce overconsumption of energy from food in out-of-home settings. Trial registration ISRCTN registry ISRCTN87225572.

Background and aims: Reducing alcohol consumption across populations would decrease the risk of a range of diseases, including many cancers, cardiovascular disease and Type 2 diabetes. The aim of the current study was to estimate the impact of using smaller bottles (37.5-versus 75-cl) and glasses (290 versus 370 ml) on consuming wine at home. Design: Randomized controlled trial of households with cross-over randomization to bottle size and parallel randomization to glass size.Setting: UK households.Participants: A total of 260 households consuming at least two 75-cl bottles of wine each week, recruited from the general population through a research agency. The majority consisted of adults who were white and of higher socio-economic position.Intervention: Households were randomized to the order in which they purchased wine in 37.5-or 75-cl bottles, to consume during two 14-day intervention periods, and further randomized to receive smaller (290 ml) or larger (350 ml) glasses to use during both intervention periods.Measurements: Volume (ml) of study wine consumed at the end of each 14-day intervention period, measured using photographs of purchased bottles, weighed on study scales.Findings: Of the randomized households, 217 of 260 (83%) completed the study as per protocol and were included in the primary analysis. There was weak evidence that smaller bottles reduced consumption: after accounting for pre-specified covariates, households consumed on average 145.7 ml (3.6%) less wine when drinking from smaller bottles than from larger bottles [95% confidence intervals (CI) = -335.5 to 43. ml; −8.3 to 1.1%; P = 0.137; Bayes factor (BF) = 2.00]. The evidence for the effect of smaller glasses was stronger: households consumed on average 253.3 ml (6.5%) less wine when drinking from smaller glasses than from larger glasses (95% CI = -517 to 10 ml; −13.2 to 0.3%; P = 0.065; BF = 2.96).Conclusions: Using smaller glasses to drink wine at home may reduce consumption.Greater uncertainty remains around the possible effect of drinking from smaller bottles.

Background: Increasing the availability of lower energy foods increases their selection. The current studies examine the extent to which this effect could be mediated by social norms – assessed by perceived popularity of foods – which may be implied by their relative availability. Methods: Study 1 (Online): 2340 UK adults estimated the perceived popularity of lower energy products. For each of eight trials, participants were randomised to one of six groups (between-subjects 3x2) to see photos of cafeteria shelves varying in the availability of lower energy options (1/4 lower energy; 1/2 lower energy; 3/4 lower energy) and fullness of shelves (fuller; emptier).Study 2 (Laboratory): 139 English adults were asked to select a snack. Participants were randomised to select from trays varying in the availability of the lower energy option (1/3 lower energy; 2/3 lower energy) and fullness of tray (fuller; emptier). Results: Study 1: Evidence for an interaction was found, such that when shelves were full, a higher proportion of lower energy options led to greater perceived popularity of lower energy products (1/4 lower energy: 40.9% (95%CIs: 40.1,41.8); 3/4 lower energy: 47.2% (46.3,48.0)), whereas when shelves were emptier, a higher proportion of lower energy options led to lower perceived popularity (1/4 lower energy: 48.4% (47.5,49.2); 3/4 lower energy: 39.2% (38.3,40.0)).Study 2: When the tray was fuller, participants were more likely – albeit non-significantly (main effects: p=0.05; interactions: p=0.07) – to select a lower energy snack when 2/3 of the available snacks were lower energy (35.7% (18.5,52.9)) than when 1/3 were lower energy (15.4% (4.2,26.5)). For emptier trays, lower energy selections decreased as the relative availability of lower energy snacks increased (1/3 lower energy snacks: 36.0% (17.9,54.1); 2/3 lower energy snacks: 27.8% (13.9,41.7)). Conclusions:These studies provide novel evidence that social norms may mediate the impact of availability on food selection. In addition, they suggest that the effect of availability may vary in different contexts, moderated by display layout through its impact on perceived product popularity. Trial registration. ISRCTN: ISRCTN10512908; 31/01/2020

BackgroundTobacco point of sale (POS) retail displays are banned in many countries, including in England, due in part to evidence linking them to greater susceptibility to smoking in children. There is no equivalent ban on displays of electronic cigarettes (e-cigarettes) or smoking paraphernalia (eg, cigarette lighters) in England, which are often positioned alongside covered tobacco storage units. This observational study describes the visibility and placement of e-cigarette and smoking paraphernalia POS displays in major tobacco retailers in two cities in England to inform future research examining their possible links to susceptibility to tobacco smoking, particularly in children.MethodsResearchers visited all small- and large-format stores of four supermarket chains and a randomly selected sample of convenience stores, in Bristol and Cambridge. A standardised checklist was used to create a total visibility score for POS displays of (a) e-cigarettes and (b) smoking paraphernalia, plus other measures of visibility and placement. These were described for the total sample and compared between areas of low, medium, and high deprivation using general linear models adjusting for store location and store type.ResultsThe visibility checklist was completed in 133 of 166 stores (80% completion rate). Both e-cigarette and smoking paraphernalia POS displays were present in 96% of stores. POS displays were highly visible across all stores: mean (SD) total visibility scores, out of 17, were 14.7 (1.8) for e-cigarettes and 12.7 (1.8) for smoking paraphernalia. There was no clear evidence of differences in visibility by area of deprivation.ConclusionE-cigarette and smoking paraphernalia POS displays are near ubiquitous and highly visible in major tobacco retailers in two cities in England. The impact of these displays on tobacco smoking in children and adults is unknown, meriting urgent research to assess their effect on susceptibility to tobacco smoking in children.