Ethnic differences in meat consumption attitudes, norms and behaviors: A survey of White, South Asian and Black ethnic groups in the UK

A reduction in meat consumption is necessary to mitigate negative impacts of climate change and adverse health outcomes. The UK has an increasingly multi-ethnic population, yet there is little research on meat consumption habits and attitudes among ethnic groups in the UK. We ran a survey (N = 1014) with quota samples for ethnic groups and analyzed attitudes, behaviors and norm perceptions of White, South Asian and Black British respondents. Most respondents believe overconsumption of red and processed meat has negative impacts on health (73.3%) and the environment (64.3%).South Asian respondents were statistically significantly less likely to be meat eaters than White respondents (OR = 0.44, 95% CIs: 0.30-0.65, t = -4.15, p = 0.000), while there was no significant difference between White and Black respondents (OR = 1.06, 95% CIs: 0.63-1.76, t = 0.21, p = 0.834). Both South Asian (OR = 2.76, 95% CIs: 1.89-4.03 t = 5.25, p = 0.000) and Black respondents (OR = 2.09, 95% CIs: 0.1.30-3.35, t = 3.06, p = 0.002) were significantly more likely to express being influenced by friends and family in their food choices than White respondents. South Asian (OR = 3.24,95% CIs: 2.17-4.84, t = 5.74, p = 0.000) and Black (OR = 2.02,95% CIs: 1.21-3.39, t = 2.69, p = 0.007) respondents were also both significantly more likely to report they would want to eat similarly to their friends and family than White respondents. Statistical analyses suggested some gender and socioeconomic differences across and among ethnic groups, which are reported and discussed. The differences in meat consumption behaviors and norm conformity between ethnic groups raises the prospect that interventions that leverage social norms may be more effective in South Asian groups than Black and White groups in the UK.

Preventing type 2 diabetes: A research agenda for behavioural science

AIMS

The aim of this narrative review was to identify important knowledge gaps in behavioural science relating to type 2 diabetes prevention, to inform future research in the field.

METHODS

Seven researchers who have published behaviour science research applied to type 2 diabetes prevention independently identified several important gaps in knowledge. They met to discuss these and to generate recommendations to advance research in behavioural science of type 2 diabetes prevention.

RESULTS

A total of 21 overlapping recommendations for a research agenda were identified. These covered issues within the following broad categories: (a) evidencing the impact of whole population approaches to type 2 diabetes prevention, (b) understanding the utility of disease-specific approaches to type 2 diabetes prevention such as Diabetes Prevention Programmes (DPPs) compared to generic weight loss programmes, (c) identifying how best to increase reach and engagement of DPPs, whilst avoiding exacerbating inequalities, (d) the need to understand mechanism of DPPs, (e) the need to understand how to increase maintenance of changes as part of or following DPPs, (f) the need to assess the feasibility and effectiveness of alternative approaches to the typical self-regulation approaches that are most commonly used, and (g) the need to address emotional aspects of DPPs, to promote effectiveness and avoid harms.

CONCLUSIONS

There is a clear role for behavioural science in informing interventions to prevent people from developing type 2 diabetes, based on strong evidence of reach, effectiveness and cost-effectiveness. This review identifies key priorities for research needed to improve existing interventions.

The impact of price promotions on confectionery and snacks on the energy content of shopping baskets: A randomised controlled trial in an experimental online supermarket

Overconsumption of foods high in fat, sugars, and salt (HFSS) poses a significant risk to health. The government in England has passed legislation that would limit some price promotions of HFSS foods within supermarkets, but evidence regarding likely impacts of these policies, especially in online settings, is limited. This study aimed to determine whether there were any differences in the energy and nutrient content of shopping baskets after removing promotions on HFSS foods in an online experimental supermarket. UK adults (n = 511) were asked to select food from four categories with a £10 budget in an online experimental supermarket: confectionery; biscuits and crackers; crisps, nuts and snacking fruit; cakes and tarts. They were randomly allocated to one of two trial arms: (1) promotions present (matched to promotion frequency seen in a major UK retailer) (n = 257), or (2) all promotions removed from all products within the target food categories (n = 254). The primary outcome analysis used linear regression to compare total energy (kcal) of items placed in shopping baskets when promotions were present vs. absent, while secondary analyses investigated differences in nutrients and energy purchased from individual food categories. Mean energy in food selected without promotions was 5156 kcal per basket (SD 1620), compared to 5536 kcal (SD 1819) with promotions, a difference of -552kcal (95%CIs: -866, -238), equivalent to 10%. There were no significant differences in energy purchased for any individual category between groups. No evidence was found of other changes in nutritional composition of baskets or of significant interactions between the impact of promotions and participant characteristics (gender, age, ethnicity) on energy purchased. Removing promotions on HFSS foods resulted in significantly less total energy selected in an online experimental supermarket study.

The impact of altering restaurant and menu option position on food selected from an experimental food delivery platform: a randomised controlled trial

BACKGROUND

Overconsumption is one of the most serious public health challenges in the UK and has been linked to increased consumption of food ordered through delivery platforms. This study tested whether repositioning foods and/or restaurant options in a simulated food delivery platform could help to reduce the energy content of users' shopping basket.

METHODS

UK adult food delivery platform users (N = 9,003) selected a meal in a simulated platform. Participants were randomly allocated to a control condition (choices listed randomly) or to one of four intervention groups, (1) food options listed in ascending order of energy content, (2) restaurant options listed in ascending order of average energy content per main meal, (3) interventions 1 and 2 combined (4) interventions 1 and 2 combined, but food and restaurant options repositioned based on a kcal/price index to display options lower in energy but higher in price at the top. Gamma regressions assessed the impact of interventions on total energy content of baskets at checkout.

RESULTS

The energy content of participants' baskets in the control condition was 1382 kcals. All interventions significantly reduced energy content of baskets: Compared to control, repositioning both foods and restaurants purely based on energy content of options resulted in the greatest effect (-209kcal; 95%CIs: -248,-168), followed by repositioning restaurants (-161kcal; 95%CIs: -201,-121), repositioning restaurants and foods based on a kcal/price index (-117kcals; 95%CI: -158,-74) and repositioning foods based on energy content (-88kcals; 95%CI: -130,-45). All interventions reduced the basket price compared to the control, except for the intervention repositioning restaurants and foods based on a kcal/price index, which increased the basket price.

CONCLUSIONS

This proof-of-concept study suggests repositioning lower-energy options more prominently may encourage lower energy food choices in online delivery platforms and can be implemented in a sustainable business model.

Effects of environmental impact and nutrition labelling on food purchasing: An experimental online supermarket study

Nutrition labels and ecolabels can support consumers to make healthier and more sustainable choices, and the former is now widespread. But there is no information on the impact of ecolabels in the presence of nutrition labels. The aims of this study were primarily to examine whether (1) ecolabels are effective at promoting sustainable purchasing behaviour if presented alongside nutrition labels; (2) and secondarily, whether nutrition labels are effective at promoting healthier purchasing if presented alongside ecolabels. Participants (N = 2730) visited an experimental online supermarket platform, and were randomised to see products with (1) environmental impact labels only; (2) nutrition (NutriScore) labels only; (3) both environmental and nutrition labels; (4) no labels. Linear regressions compared the mean environmental impact scores (EIS; primary outcome) and health scores of products in participants' shopping baskets across each condition. Compared to control (no labels) there were significant reductions in the EIS when environmental impact labels were presented: Alone (-1.3, 95%CI: -2.3 to -0.4) or With nutrition labels (-2.0, 95%CI: -2.9 to -1.0), with no evidence of differences in effectiveness between these two conditions. There was no evidence of an impact of nutrition labels on either the EIS or the healthiness of purchases, both when nutrition labels were shown alone and when ecolabels were also present. Environmental impact labels may be effective at encouraging more sustainable purchases alone or when used alongside nutrition labels. This adds to the evidence base on the feasibility and effectiveness of environmental impact labelling as an important measure to change dietary behaviour to improve planetary health.

Effects of environmental impact labels on the sustainability of food purchases: Two randomised controlled trials in an experimental online supermarket

Providing consumers with product-specific environmental impact information for food products (ecolabels) may promote more sustainable purchasing, needed to meet global environmental targets. Two UK studies investigated the effectiveness of different ecolabels using an experimental online supermarket platform. Study 1 (N = 1051 participants) compared three labels against control (no label), while Study 2 (N = 4979) tested four designs against control. Study 1 found significant reductions in the environmental impact score (EIS) for all labels compared to control (labels presented: values for four environmental indicators [-3.9 percentiles, 95%CIs: -5.2,-2.6]; a composite score [taking values from A to E; -3.9, 95%CIs: -5.2,-2.5]; or both together [-3.2, 95%CIs: -4.5,-1.9]). Study 2 showed significant reductions in EIS compared to control for A-E labels [-2.3, 95%CIs: -3.0,-1.5], coloured globes with A-E scores [-3.2, 95%CIs:-3.9,-2.4], and red globes highlighting ’worse’ products [-3.2, 95%CIs:-3.9,-2.5]. There was no evidence that green globes highlighting ’better’ products were effective [-0.5, 95%CIs:-1.3,0.2]. Providing ecolabels is a promising intervention to promote the selection of more sustainable products.

Evaluation of physical activity calorie equivalent (PACE) labels' impact on energy purchased in cafeterias: A stepped-wedge randomised controlled trial

BACKGROUND

A recent meta-analysis suggested that using physical activity calorie equivalent (PACE) labels results in people selecting and consuming less energy. However, the meta-analysis included only 1 study in a naturalistic setting, conducted in 4 convenience stores. We therefore aimed to estimate the effect of PACE labels on energy purchased in worksite cafeterias in the context of a randomised study design.

METHODS AND FINDINGS

A stepped-wedge randomised controlled trial (RCT) was conducted to investigate the effect of PACE labels (which include kcal content and minutes of walking required to expend the energy content of the labelled food) on energy purchased. The setting was 10 worksite cafeterias in England, which were randomised to the order in which they introduced PACE labels on selected food and drinks following a baseline period. There were approximately 19,000 workers employed at the sites, 72% male, with an average age of 40. The study ran for 12 weeks (06 April 2021 to 28 June 2021) with over 250,000 transactions recorded on electronic tills. The primary outcome was total energy (kcal) purchased from intervention items per day. The secondary outcomes were: energy purchased from non-intervention items per day, total energy purchased per day, and revenue. Regression models showed no evidence of an overall effect on energy purchased from intervention items, -1,934 kcals per site per day (95% CI -5,131 to 1,262), p = 0.236, during the intervention relative to baseline, equivalent to -5 kcals per transaction (95% CI -14 to 4). There was also no evidence for an effect on energy purchased from non-intervention items, -5 kcals per site per day (95% CI -513 to 504), p = 0.986, equivalent to 0 kcals per transaction (95% CI -1 to 1), and no clear evidence for total energy purchased -2,899 kcals per site (95% CI -5,810 to 11), p = 0.051, equivalent to -8 kcals per transaction (95% CI -16 to 0). Study limitations include using energy purchased and not energy consumed as the primary outcome and access only to transaction-level sales, rather than individual-level data.

CONCLUSION

Overall, the evidence was consistent with PACE labels not changing energy purchased in worksite cafeterias. There was considerable variation in effects between cafeterias, suggesting important unmeasured moderators.

TRIAL REGISTRATION

The study was prospectively registered on ISRCTN (date: 30.03.21; ISRCTN31315776).

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 < 0.001) and eco-friendly (Z = −13.27, p < 0.001) food choices than the latter. Perceptions of norms referring to the close group were significantly associated with the environmental (β = −0.90, 95% CIs: −1.49, −0.28) and health (β = −0.38 p < 0.05, 95% CIs: −0.68, −0.08) impacts of participants’ food choices in a virtual shopping task. No such relationship was found for norms referring to the distant group for both environmental (β =0.43, 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.

Acceptability of policies to reduce consumption of red and processed meat: A population-based survey experiment

Policies to reduce meat consumption are needed to help achieve climate change targets, and could also improve population health. Public acceptability can affect the likelihood of policy implementation. This study estimated the acceptability of policies to reduce red and processed meat consumption, and whether acceptability differed when policies were framed as benefitting health or the environment. In an online experiment, 2215 UK adults rated the acceptability of six policies, presented in a randomised order. Prior to rating policies, participants were randomised to one of two framing conditions, with policy outcomes described either as benefitting health or the environment. Regression models examined differences in the primary outcome - policy acceptability (rated on a 7-point scale) - by framing. Labels were the most accepted policy (48% support), followed by a media campaign (45%), reduced availability (40%) and providing incentives (38%). Increasing price (27%) and banning advertising (26%) were the least accepted. A substantial proportion of participants neither supported nor opposed most policies (26-33%), although this fell to 16% for increasing price. There was no evidence that framing policy benefits from a health or environment perspective influenced acceptability (-0.06, 95%CIs: 0.18,0.07). Fewer than half of the UK sample expressed support for any of six policies to reduce meat consumption, regardless of framing measures as benefitting health or the environment. Conversely, fewer than half expressed opposition, with the exception of price, suggesting considerable scope to influence public opinion in support of meat reduction measures to meet environmental and health goals.

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.

TRIAL REGISTRATION

ISRCTN ( http://www.isrctn.com/ISRCTN27598623 ; 3/12/19 [Study 1]; http://www.isrctn.com/ISRCTN61010183 ; 20/4/20 [Study 2]).

Impact of increasing the relative availability of meat-free options on food selection: two natural field experiments and an online randomised trial

BACKGROUND

Increasing the availability of lower energy-density foods is a promising intervention to encourage healthier food purchasing but few studies have examined the effect of increasing availability of meat-free meals to promote more sustainable purchasing. We report three studies, all examining the impact of altering the availability of meat-free meals on meal selection.

METHODS

Study 1 (a natural experiment in one university cafeteria) examined the impact of altering the ratio of meat-free meals (one meat-free and two meat, to two meat-free and one meat) on weekly sales of meals containing meat. Study 2 (a natural experiment in 18 worksite cafeterias) examined the impact on meat-free meal sales of a menu change designed to increase the availability of meat-free meals. Study 3 (an online study of 2205 UK-representative adults) compared meal selections when participants were randomised to ranges comprised of (a) one meat-free, three meat options; (b) two meat-free, two meat; or (c) three meat-free, one meat.

RESULTS

Study 1 suggested a significant decrease in the proportion of sales of meat options when the availability of meat-free options increased (- 19.9 percentage points; 95%CIs:-25.2,-14.6), with no evidence of changes to meat-based meal sales in other university cafeterias during the same period. Findings from Study 2 were mixed: multilevel regressions found no evidence of an increase in meat-free meals following the menu change (2.3 percentage points; 95%CIs: - 1.3,5.9), while interrupted time-series analyses suggested sales did increase (2.3; 95%CIs: 0.4,4.2), but implementation of the planned change was limited. In Study 3 reducing meat-free options from 50 to 25% reduced participants' selection of meat-free options (odds ratio 0.35; 95%CIs: 0.26,0.46), while increasing meat-free options from 50 to 75% increased meat-free selections (odds ratio 2.43; 95%CIs: 1.94,3.04). There was no evidence effects were moderated by gender, socioeconomic status or usual meat consumption.

CONCLUSION

Increasing the availability of meat-free options is effective at reducing meat selection and purchasing for different ratios of meat to meat-free options. The magnitude of the effect is uncertain, but with no evidence of differences in response by demographic groups when directly tested.

TRIAL REGISTRATION

Study 3: Open Science Framework; https://osf.io/ze9c6 ; 6/8/2020.

Size and shape of plates and size of wine glasses and bottles: impact on self-serving of food and alcohol

Background

The physical properties of tableware could influence selection and consumption of food and alcohol. There is considerable uncertainty, however, around the potential effects of different sizes and shapes of tableware on how much food and alcohol people self-serve. These studies aimed to estimate the impact of: 1. Plate size and shape on amount of food self-served; 2.Wine glass and bottle size on amount of wine self-poured.

Methods

140 adults participated in two laboratory studies—each using randomised within-subjects factorial designs—where they self-served food (Study 1) and wine (Study 2):

Study 1: 3 plate sizes (small; medium; large) × 2 plate shapes (circular; square).

Study 2: 3 wine glass sizes (small; medium; large) × 2 wine bottle sizes (75 cl; 50 cl).

Results

Study 1: There was a main effect of plate size: less was self-served on small (76 g less, p < 0.001) and medium (41 g less, p < 0.001) plates, compared to large plates. There was no evidence for a main effect of plate shape (p = 0.46) or a size and shape interaction (p = 0.47).

Study 2: There was a main effect of glass size: less was self-served in small (34 ml less, p < 0.001) and medium (17 ml less, p < 0.001) glasses, compared to large glasses. There was no evidence of a main effect of bottle size (p = 0.20) or a glass and bottle size interaction (p = 0.18).

Conclusions

Smaller tableware (i.e. plates and wine glasses) decreases the amount of food and wine self-served in an initial serving. Future studies are required to generate estimates on selection and consumption in real world settings when numerous servings are possible.

Protocol registration information: OSF (https://osf.io/dj3c6/) and ISRCTN (10.1186/ISRCTN66774780).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40359-021-00645-z.

Impact of altering the available food options on selection: Potential mediation by social norms

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.

Impact of decreasing the proportion of higher energy foods and reducing portion sizes on food purchased in worksite cafeterias: A stepped-wedge randomised controlled trial

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.

Straight-sided beer and cider glasses to reduce alcohol sales for on-site consumption: A randomised crossover trial in bars

BACKGROUND

Straight-sided glasses can slow the rate of lager consumption in a laboratory setting compared with curved glasses. Slower drinking rates may lower overall alcohol consumption. Glass shape is therefore a potential target for intervention. The aim of this randomised crossover trial was to estimate the impact of serving draught beer and cider in straight-sided glasses, compared with usual, predominantly curved glasses, on alcohol sales for on-site consumption in bars.

METHODS

Twenty-four bars in England completed two intervention periods (A) and two control periods (B) in a randomised order: 1) BABA; 2) BAAB; 3) ABBA; or 4) ABAB. Each period lasted two weeks and involved serving draught beer and cider in either straight-sided glasses (A) or the venue's usual glasses (≥75% curved; B). The primary outcome was the mean volume (in litres) of draught beer and cider sold weekly, compared between A and B periods using a paired-samples t-test on aggregate data. A regression model adjusted for season, order, special events, and busyness.

FINDINGS

Mean weekly volume sales of draught beer and cider was 690·9 L (SD 491·3 L) across A periods and 732·5 L (SD 501·0 L) across B periods. The adjusted mean difference (A minus B) was 8·9 L per week (95% CI -45·5 to 63·3; p = 0·737).

INTERPRETATION

This study provides no clear evidence that using straight-sided glasses, compared with usual, predominantly curved glasses, reduces the volume of draught beer and cider sold for on-site consumption in bars.

Impact of increasing the availability of healthier vs. less-healthy food on food selection: a randomised laboratory experiment

Background

Environmental cues shape behaviour, but few studies compare the impact of targeting healthier vs. less-healthy cues. One online study suggested greater impact on selection from increasing the number of less-healthy (vs. healthier) snacks. The current study aimed to: (1) extend the previous study by using physically-present snacks for immediate consumption; (2) explore responsiveness by socio-economic position; (3) investigate possible mediators (response inhibition, food appeal) of any socio-economic differences in selection.

Methods

In a between-subjects laboratory experiment UK adults (n = 417) were randomised according to their ID number (without blinding) to one of three ranges of options: Two healthier, two less-healthy [“Equal”] (n = 136); Six healthier, two less-healthy [“Increased Healthier”] (n = 143); Two healthier, six less-healthy [“Increased Less-Healthy”] (n = 138). Participants completed measures of response inhibition and food appeal, and selected a snack for immediate consumption from their allocated range. The primary outcome was selection of a healthier (over less-healthy) snack.

Results

The odds of selecting a less-healthy snack were 2.9 times higher (95%CIs:1.7,5.1) in the Increased Less-Healthy condition compared to the Equal condition. The odds of selecting a healthier snack were 2.5 times higher (95%CIs:1.5,4.1) in the Increased Healthier (vs. Equal) condition. There was no significant difference in the size of these effects (− 0.2; 95%CIs:-1.1,0.7). Findings were inconclusive with regard to interactions by education, but the direction of effects was consistent with potentially larger impact of the Increased Healthier condition on selection for higher-educated participants, and potentially larger impact of the Increased Less-Healthy condition for less-educated participants.

Conclusions

A greater impact from increasing the number of less-healthy (over healthier) foods was not replicated when selecting snacks for immediate consumption: both increased selections of the targeted foods with no evidence of a difference in effectiveness. The observed pattern of results suggested possible differential impact by education, albeit not statistically significant. If replicated in larger studies, this could suggest that removing less-healthy options has the potential to reduce health inequalities due to unhealthier diets. Conversely, adding healthier options could have the potential to increase these inequalities.

Trial registration

ISRCTN: ISRCTN34626166; 11/06/2018; Retrospectively registered.

Are meat options preferred to comparable vegetarian options? An experimental study

OBJECTIVE

Reducing meat consumption would have substantial benefits both in terms of health and environmental impact, but meat options may be more attractive to customers than meat-free options. This study tested this by presenting UK adults (n = 540) with a series of pictures showing two meal options and asking them to select which they would prefer to eat right now. They completed this task for every possible pair from a pool of six comparator meat-based options and six target options (66 pairs). Participants all saw identical comparator options, and were randomised to see the same pictures of target options but with descriptions that suggested they were either meat-based or vegetarian.

RESULTS

Selections were used to rank the options for each individual from 1 (most-selected) to 12 (least-selected). Vegetarian target options were ranked worse [by 1.23 places (95% CI: 1.02, 1.44)] than meat target options. Higher self-reported consumption of meat predicted worse mean rankings of target options when these were vegetarian, but not when target options were meat-based. This suggests meat options are preferred to equivalent vegetarian options and may be more likely to be selected. This has implications for interventions aiming to reduce meat consumption to make diets healthier and more sustainable.

Impact of bottle size on in-home consumption of wine: a randomized controlled cross-over trial

AIM

To assess the impact of purchasing wine in 50 cl bottles compared with 75 cl bottles on the amount of wine consumed at home.

DESIGN

Cross-over randomized controlled trial with a 'usual behaviour' period of a maximum of 3 weeks between conditions.

SETTING

Households in the United Kingdom.

PARTICIPANTS

One hundred and eighty-six households that consumed between two and eight 75 cl bottles of wine each week.

INTERVENTION

Households were randomized to the order in which they purchased wine in two bottle sizes. During two 14-day intervention periods, households purchased a pre-set volume of wine-based on their baseline self-reported weekly consumption-in either 75 cl bottles or 50 cl bottles. On days 7 and 14 of each study period, participating households sent photographs of each purchased wine bottle.

MEASUREMENTS

The primary outcome was the volume of study wine in millilitres (ml) consumed during each study period estimated through returned photographs. The secondary outcome was the rate of consumption measured by the mean number of days taken to drink 1.5 litres from each bottle size.

FINDINGS

One hundred and sixty-six of 186 enrolled households satisfactorily completed the study. After accounting for pre-specified covariates, 191.1 ml [95% confidence interval (CI) = 42.03-339.2] or 4.5% (95% CI = 1.0-7.9%) more wine was consumed per 14-day period from 75-cl bottles than from 50-cl bottles. Consumption was 5.8% faster (95% CI = -10.9 to -0.4%) from 75 cl bottles than from 50 cl bottles.

CONCLUSIONS

Consuming wine at home from 50 cl bottles, compared with 75 cl bottles, may reduce both amount consumed and rate of consumption.

Glassware design and drinking behaviours: a review of impact and mechanisms using a new typology of drinking behaviours

Much of the global burden of disease is attributable to unhealthy behaviour, including excessive consumption of alcohol and sugar-sweetened beverages. Developing effective methods to change these drinking behaviours could inform policies to improve population health. In line with an increasing interest in environmental-level interventions - i.e., changing the environment in which a behaviour occurs in order to change the behaviour of interest - this review first describes the existing evidence of the impact of glassware design (including capacity and shape) on drinking behaviours (e.g., at the 'micro' level - including sip size, as well as at the macro level - including amount consumed). The roles of two sets of possible underlying mechanisms - perception and affordance - are also explored. Finally, this review sets out a provisional typology of drinking behaviours to enable more systematic approaches to the study of these behaviours. While there is a paucity of evidence - in particular on measures of consumption - this growing evidence base suggests promising targets for novel interventions involving glassware design to reduce the consumption of drinks that harm health.Trial registration: ISRCTN.org identifier: ISRCTN10456720.

The effect of wine glass size on volume of wine sold: a mega-analysis of studies in bars and restaurants

AIM

To estimate the effects of wine glass size on volume of wine sold in bars and restaurants.

DESIGN

A mega-analysis combining raw (as opposed to aggregate-level) data from eight studies conducted in five establishments. A multiple treatment reversal design was used for each data set, with wine glass size changed fortnightly while serving sizes were unaffected, in studies lasting between 14 and 26 weeks.

SETTING AND PARTICIPANTS

Five bars and restaurants in England participated in studies between 2015 and 2018, using wine glasses of five sizes: 250, 300, 370, 450 and 510 ml, with the largest size only used in bars.

MEASUREMENTS

Daily volume of wine sold by the glass, bottle or carafe for non-sparkling wine were recorded at bars (594 days) and restaurants (427 days), averaging 4 months per study.

FINDINGS

Mega-analysis combining data from bars did not find a significant effect of glass size on volume of wine sold compared with 300-ml glasses: the volume of wine sold using 370-ml glasses was 0.5% lower [95% confidence interval (CI) = -8.1% to 6.1%], using 450-ml glasses was 1.0% higher (95% CI = -9.1 to 12.2) and using 510-ml glasses was 0.4% lower (95% CI = -9.4 to 9.4). For restaurants, compared with 300-ml glasses, the volume of wine sold using 250-ml glasses did not show a significant difference: 9.6% lower (95% CI = -19.0 to 0.7). Using 370-ml glasses the volume of wine sold was 7.3% higher (95% CI = 1.5% to 13.5%); no significant effect was found using 450-ml glasses: 0.9% higher (95% CI = -5.5 to 7.7).

CONCLUSIONS

The volume of wine sold in restaurants in England may be greater when 370-ml glasses are used compared with 300-ml wine glasses, but may not be in bars. This might be related to restaurants compared with bars selling more wine in bottles and carafes, which require free-pouring.

Glass shape influences drinking behaviours in three laboratory experiments

Reducing consumption of drinks which contain high levels of sugar and/or alcohol may improve population health. There is increasing interest in health behaviour change approaches which work by changing cues in physical environments ("nudges"). Glassware represents a modifiable cue in the drinking environment that may influence how much we drink. Here, we report three laboratory experiments measuring consumption of soft drinks served in different glasses (straight-sided vs. outward-sloped), using distinct paradigms to measure drinking. In Study 1 (N = 200), though total drinking time was equivalent, participants consumed a soft drink with a more 'decelerated' trajectory from outward-sloped tumblers, characterised by a greater amount consumed in the first half of the drinking episode. In Study 2 (N = 72), during a bogus taste test, participants consumed less from straight-sided wine flutes than outward-sloped martini coupes. In Study 3 (N = 40), using facial electromyography to explore a potential mechanism for decreased consumption, straight-sided glasses elicited more 'pursed' lip embouchures, which may partly explain reduced consumption from these glasses. Using a combination of methods, including objective measures of volume drunk and physiological measures, these findings suggest that switching to straight-sided glasses may be one intervention contributing to the many needed to reduce consumption of health-harming drinks.

Altering the availability of products within physical micro-environments: a conceptual framework

Altering the availability of products (e.g. food, alcohol or tobacco products) is one potential intervention to change behaviours to help reduce preventable premature deaths worldwide. However, research on these interventions lacks consistent conceptualisation, hindering clear reporting and cumulative synthesis. This paper proposes a conceptual framework – categorising intervention types and summarising constituent components – with which interventions can be reliably described and evidence synthesised. Three principal distinctions are proposed: interventions altering: (i) Absolute Availability (changing the overall number of options, while keeping the proportions comprised by any subsets of options constant); (ii) Relative Availability (changing the proportion comprised by a subset of options, yet keeping the overall number of options constant); (iii) Absolute and Relative Availability (changing both the overall number of options and the proportions comprised by subsets of options). These are subdivided into those targeting (a) a product or (b) a category of products. Mechanisms that might underlie each of these intervention types are discussed, and implications for future research highlighted. The proposed framework aims to facilitate study of a set of interventions that could contribute significantly to healthier behaviour across populations.

Increasing the proportion of healthier foods available with and without reducing portion sizes and energy purchased in worksite cafeterias: protocol for a stepped-wedge randomised controlled trial

BACKGROUND

Overconsumption of energy from food contributes to high rates of overweight and obesity in many populations. A promising set of interventions tested in pilot studies in worksite cafeterias, suggests energy intake may be reduced by increasing the proportion of healthier - i.e. lower energy - food options available, and decreasing portion sizes. The current study aims to assess the impact on energy purchased of i. increasing the proportion of lower energy options available; ii. combining this with reducing portion sizes, in a full trial.

METHODS

A stepped-wedge randomised controlled trial in 19 worksite cafeterias, where the proportion of lower energy options available in targeted food categories (including main meals, snacks, and cold drinks) will be increased; and combined with reduced portion sizes. The primary outcome is total energy (kcal) purchased from targeted food categories using a pooled estimate across all sites. Follow-up analyses will test whether the impact on energy purchased varies according to the extent of intervention implementation.

DISCUSSION

This study will provide the most reliable estimate to date of the effect sizes of two promising interventions for reducing energy purchased in worksite cafeterias.

TRIAL REGISTRATION

The study was prospectively registered on ISRCTN (date: 24.05.19; TRN: ISRCTN87225572; doi: https://doi.org/10.1186/ISRCTN87225572).

Altering the availability of healthier vs. less healthy items in UK hospital vending machines: a multiple treatment reversal design

BACKGROUND

Altering the availability of healthier or less-healthy products may increase healthier purchases, but evidence is currently limited. The current study aimed to investigate the impact of altering the absolute-and-relative availability of healthier and less-healthy products - i.e. simultaneously altering the number of options available and the proportion of healthier options - in hospital vending machines.

METHODS

An adapted multiple treatment reversal design was used, altering products available in ten vending machines serving snack foods and/or cold drinks in one English hospital. Machines were randomised to one of two sequences for the seven 4-week study periods: ABCADEA or ADEABCA. In Condition A (study periods 1, 4 and 7) the proportions of healthier products were standardised across all machines, so that 25% of all snack slots and 75% of drink slots were healthier. In Condition B, 20% of vending machine slots were emptied by removing less-healthy products. In Condition C, the empty slots created in Condition B were filled with healthier products. Conditions D and E were operationalised in the same way as B and C, except healthier products were removed in D, and then less-healthy products added in E. Sales data were obtained from machine restocking records. Separate linear mixed models were conducted to examine the impact of altering availability on energy purchased (kcal) from (i) snacks or (ii) drinks each week, with random effects for vending machine.

RESULTS

The energy purchased from drinks was reduced when the number of slots containing less-healthy drinks was decreased, compared to standardised levels (- 52.6%; 95%CI: - 69.3,-26.9). Findings were inconclusive for energy purchased from snacks when less-healthy snack slots were reduced (- 17.2%; 95%CI: - 47.4,30.5). Results for altering the number of slots for healthier drinks or snacks were similarly inconclusive, with no statistically significant impact on energy purchased.

CONCLUSIONS

Reducing the availability of less-healthy drinks could reduce the energy purchased from drinks in vending machines. Further studies are needed to establish whether any effects might be smaller for snacks, or found with higher baseline proportions of healthier options.

The impact of 'on-pack' pictorial health warning labels and calorie information labels on drink choice: A laboratory experiment

Sugar-sweetened beverages (SSBs) are one of the largest added sugar sources to diets in the UK and USA. Health warning labels reduce hypothetical selection of SSBs in online studies but uncertainty surrounds their impact on selection of drinks for consumption. Calorie information labels are also promising but their impact on SSB selection is unclear. This laboratory study assessed the impact on SSB selection of ‘on-pack’ labels placed directly on physical products: i.a pictorial health warning label depicting an adverse health consequence of excess sugar consumption; and ii.calorie information labels. Potential moderation of any effects by socio-economic position (SEP) was also examined. Participants - 401 adults, resident in England, approximately half of whom were of lower SEP and half of higher SEP, were asked to select a drink from a range of two non-SSBs and four SSBs (subsequent to completing a separate study assessing the effects of food availability on snack selection). The drinks included ‘on-pack’ labels according to randomisation: Group 1: pictorial health warning label on SSBs; Group 2: calorie information label on all drinks; Group 3: no additional label. The primary outcome was the proportion of participants selecting an SSB. Compared to not having additional labels (39%), neither the pictorial health warning label (40%) nor calorie information labels (43%) affected the proportion of participants selecting an SSB. Lower SEP participants (45%) were more likely to select an SSB compared to those of higher SEP (35%), but SEP did not moderate the impact of labels on drink selection. In conclusion, pictorial health warning labels may be less effective in reducing SSB selection in lab-based compared with online settings, or depending on label design and placement. Findings suggest that effects might be absent when choosing from real products with actual ‘on-pack’ labels, positioned in a ‘realistic’ manner. Field studies are needed to further assess the impact of ‘on-pack’ SSB warning labels in real-world settings to rule out the possible contribution of study design factors.

Wine glass size and wine sales: four replication studies in one restaurant and two bars

Objective

Previous research suggests that wine glass size affects sales of wine in bars, with more wine purchased when served in larger glasses. The current four studies, conducted in one restaurant (Studies 1 and 2) and two bars (Studies 3 and 4) in Cambridge, England, aim to establish the reproducibility of this effect of glass size on sales. A multiple treatment reversal design was used, involving wine being served in sequential fortnightly periods in different sized glasses of the same design (290 ml, 350 ml, and 450 ml). The primary outcome was daily wine volume (ml) sold.

Results

Restaurant: Daily wine volume sold was 13% (95% CI 2%, 24%) higher when served with 350 ml vs. 290 ml glasses in Study 1. A similar direction of effect was seen in Study 2 (6%; 95% CI − 1%, 15%). Bars: Daily wine volume sold was 21% (95% CI 9%, 35%) higher when served with 450 ml vs. 350 ml glasses in Study 3. This effect was not observed in Study 4 (− 7%, 95% CI − 16%, 3%). Meaningful differences were not demonstrated with any other glass comparison. These results partially replicate previous studies showing that larger glasses increase wine sales. Considerable uncertainty remains about the magnitude of any effect and the contexts in which it might occur.

Trial registration Study 1: ISRCTN17958895 (21/07/2017), Study 2: ISRCTN17097810 (29/03/2018), Study 3 and 4: ISRCTN39401124 (10/05/2018)

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4477-8) contains supplementary material, which is available to authorized users.

What is the impact of increasing the prominence of calorie labelling? A stepped wedge randomised controlled pilot trial in worksite cafeterias

Background

Calorie labelling may help to reduce energy consumption, but few well-controlled experimental studies have been conducted in real world settings. In a previous randomised controlled pilot trial we did not observe an effect of calorie labelling on energy purchased in worksite cafeterias. In the present study we sought to enhance the effect by making the labels more prominent, and to address the operational challenges reported previously by worksites.

Methods

Three worksite cafeterias were randomised in a stepped wedge design to start the intervention at one of three fortnightly periods between March and July 2018. The intervention comprised introducing prominent calorie labelling for all cafeteria products for which calorie information was available (on average 87% of products offered across the three sites were labelled). Calorie content was displayed in bold capitalised Verdana typeface with a minimum font size of 14 e.g.120 CALORIES. Feasibility and acceptability were assessed using post-intervention surveys with cafeteria patrons and semi-structured interviews with managers. Effectiveness was assessed using total daily energy (kcal) purchased from intervention items across the three sites, analysed using semi-parametric GAMLSS models.

Results

Recruitment and retention of worksite cafeterias proved feasible: all three randomised sites successfully completed the study. Post-intervention feedback suggested high levels of intervention acceptability: 87% of responding patrons wanted calorie labelling to remain in place. No effect of the intervention on daily energy purchased was observed: −0.6% (95%CI -2.5 to 1.2, p = .487). By-site analyses showed similar null effects at each of the three sites, all ps > .110.

Conclusions

There was no evidence that prominent calorie labelling changed daily energy purchased across three English-based worksite cafeterias. The intervention was feasible to implement and acceptable to patrons and managers.

Impact of increasing the proportion of healthier foods available on energy purchased in worksite cafeterias: A stepped wedge randomized controlled pilot trial

Increasing the proportion of healthier foods available could encourage healthier consumption, but evidence to date is limited in scope and quality. The current study aimed to: (a) examine the feasibility and acceptability of intervening to change product availability in worksite cafeterias; and (b) estimate the impact on energy purchased of increasing the proportion of healthier (i.e. lower energy) cooked meals, snacks, cold drinks and sandwiches. Six English worksite cafeterias increased the proportion of healthier foods available, aiming to keep the total number of options constant, in a stepped wedge randomized controlled pilot trial conducted between January and May 2017. The intervention was generally successfully implemented and acceptable to clientele. Generalized linear mixed models showed a reduction of 6.9% (95%CI: -11.7%, -1.7%, p = 0.044) in energy (kcal) purchased from targeted food categories across all sites. However, impact varied across sites, with energy purchased from targeted categories significantly reduced in two sites (-10.7% (95%CI: -18.1% to -2.6%, p = 0.046); -18.4% (95%CI: -26.9% to -8.8%, p = 0.013)), while no significant differences were seen in the other four sites. Overall, increasing the proportion of healthier options available in worksite cafeterias seems a promising intervention to reduce energy purchased but contextual effects merit further study.

Availability of healthier vs. less healthy food and food choice: an online experiment

BACKGROUND

Our environments shape our behaviour, but little research has addressed whether healthier cues have a similar impact to less healthy ones. This online study examined the impact on food choices of the number of (i) healthier and (ii) less healthy snack foods available, and possible moderation by cognitive load and socioeconomic status.

METHODS

UK adults (n = 1509) were randomly allocated to one of six groups (two cognitive load x three availability conditions). Participants memorised a 7-digit number (7777777: low cognitive load; 8529713: high cognitive load). While remembering this number, participants chose the food they would most like to eat from: (a) two healthier and two less healthy foods, (b) six healthier and two less healthy foods, or (c) two healthier and six less healthy foods.

RESULTS

Compared to being offered two healthier and two less healthy options, the odds of choosing a healthier option were twice as high (Odds Ratio (OR): 2.0, 95%CI: 1.6, 2.6) with four additional healthier options, while the odds of choosing a less healthy option were four times higher (OR: 4.3, 95%CI: 3.1, 6.0) with four additional less healthy options. There were no significant main effects or interactions with cognitive load or socioeconomic status.

CONCLUSIONS

This study provides a novel test of the impact of healthier vs. less healthy food cues on food choice, suggesting that less healthy food cues have a larger effect than healthier ones. Consequently, removing less healthy as opposed to adding healthier food options could have greater impact on healthier choices. Studies are now needed in which choices are made between physically-present foods.

Impact of glass shape on time taken to drink a soft drink: A laboratory-based experiment

BACKGROUND

Glassware design may affect drinking behaviour for alcoholic beverages, with glass shape and size influencing drinking speed and amount consumed. Uncertainty remains both about the extent to which these effects are restricted to alcohol and the underlying mechanisms. The primary aim of the current study was to examine the effect of differently shaped glasses on time taken to drink a soft drink. The secondary aim was to develop hypotheses about mechanisms concerning micro-drinking behaviours and perceptual effects.

METHOD

In a single-session experiment, 162 participants were randomised to receive 330ml of carbonated apple juice in a glass that was either inward-sloped, straight-sided, or outward-sloped. The primary outcome measure was total drinking time. Secondary outcome measures included micro-drinking behaviours (sip size, sip duration, interval duration), and perceptual measures (midpoint bias, drink enjoyment).

RESULTS

Participants drank 21.4% faster from the outward-sloped glass than from the straight-sided glass [95%CI: 0.2%,38.0%] in adjusted models. They were also 18.2% faster from the inward-sloped glass than the straight-sided glass, but this did not reach statistical significance with wide confidence intervals also consistent with slower drinking [95%CI: -3.8%,35.6%]. Larger sips were associated with faster drinking times (Pearson's r(162) = -.45, p < .001). The direction of effects suggested sips were larger from the outward-sloped and inward-sloped glasses, compared to the straight-sided glass (15.1%, 95%CI: -4.3%,38.0%; 19.4%, 95%CI: -0.5%,43.6%, respectively). There were no significant differences between glasses in mean sip or interval duration. Bias in midpoint estimation was greater for the outward-sloped glass (12.9ml, 95%CI: 6.6ml,19.2ml) than for the straight-sided glass, although the degree of bias was not associated with total drinking time (Pearson's r(162) = 0.01, p = .87).

DISCUSSION

Individuals drank a soft drink more quickly from an outward-sloped glass, relative to a straight-sided glass. Micro-drinking behaviours, such as sip size, are promising candidates for underlying mechanisms.

Impact of calorie labelling in worksite cafeterias: a stepped wedge randomised controlled pilot trial

BACKGROUND

For working adults, about one-third of energy is consumed in the workplace making this an important context in which to reduce energy intake to tackle obesity. The aims of the current study were first, to identify barriers to the feasibility and acceptability of implementing calorie labelling in preparation for a larger trial, and second, to estimate the potential impact of calorie labelling on energy purchased in worksite cafeterias.

METHODS

Six worksite cafeterias were randomised to the intervention starting at one of six fortnightly periods, using a stepped wedge design. The trial was conducted between August and December 2016, across 17 study weeks. The intervention comprised labelling all cafeteria products for which such information was available with their calorie content (e.g. "250 Calories") displayed in the same font style and size as for price. A post-intervention survey with cafeteria patrons and interviews with managers and caterers were used to assess the feasibility and acceptability of the intervention. Intervention impact was assessed using generalised linear mixed modelling. The primary outcome was the total energy (kcal) purchased from intervention items in each cafeteria each day.

RESULTS

Recruitment and retention of worksite cafeterias proved feasible, with post-intervention feedback suggesting high levels of intervention acceptability. Several barriers to intervention implementation were identified, including chefs' discretion at implementing recipes and the manual recording of sales data. There was no overall effect of the intervention: -0.4% (95%CI -3.8 to 2.9, p = .803). One site showed a statistically significant effect of the intervention, with an estimated 6.6% reduction (95%CI -12.9 to - 0.3, p = .044) in energy purchased in the day following the introduction of calorie labelling, an effect that diminished over time. The remaining five sites did not show robust changes in energy purchased when calorie labelling was introduced.

CONCLUSIONS

A calorie labelling intervention was acceptable to both cafeteria operators and customers. The predicted effect of labelling to reduce energy purchased was only evident at one out of six sites studied. Before progressing to a full trial, the calorie labelling intervention needs to be optimised, and a number of operational issues resolved.

TRIAL REGISTRATION

ISRCTN52923504 ; Registered: 22/09/2016; retrospectively registered.

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 300, 370, 510 ml (Bar 1) and 300 and 510 ml (Bar 2). Customers purchased their choice of a 750 ml bottle, or standard UK measures of 125, 175 or 250 ml of wine, each of which was served with the same glass.

Results

Bar 1 Daily wine volume (ml) purchased was 10.5% (95% CI 1.0, 20.9) higher when sold in 510 ml compared to 370 ml glasses; but sales were not significantly higher with 370 ml versus 300 ml glasses (6.5%, 95% CI −5.2, 19.6). Bar 2 Findings were inconclusive as to whether daily wine purchased differed when using 510 ml versus 300 ml 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.

Trial registration This study is a replication study, based on the procedure set out in the trial registration for the study that it attempts to replicate (ISRCTN registry: ISRCTN12018175)

Micro-drinking behaviours and consumption of wine in different wine glass sizes: a laboratory study

Background

Tableware size may influence how much food and non-alcoholic drink is consumed. Preliminary evidence of the impact of glass size on purchasing of alcoholic drinks shows an increase in wine sales of almost 10% when the same portion of wine is served in a larger glass. The primary aim of the current study is to test if micro-drinking behaviours act as a mechanism that could underlie this effect, through an increase in drinking rate, sip duration and/or number of sips from a larger glass.

Methods

In a between-subjects experimental design, 166 young women were randomised to drink a 175 ml portion of wine from either a smaller (250 ml) or larger (370 ml) wine glass. Primary outcomes were three micro-drinking behaviours, assessed observationally using video recordings: drinking rate, sip number and sip duration. Other possible mechanisms examined were satisfaction with the perceived amount of wine served and pleasure of the drinking experience, assessed using self-report measures.

Results

Wine drunk from the larger, compared with the smaller glass, was consumed more slowly and with shorter sip duration, counter to the hypothesised direction of effect. No differences were observed in any of the other outcome measures.

Conclusions

These findings provide no support for the hypothesised mechanisms by which serving wine in larger wine glasses increases consumption. While micro-drinking behaviours may still prove to be a mechanism explaining consumption from different glass sizes, cross-validation of these results in a more naturalistic setting is needed.

Physical micro-environment interventions for healthier eating in the workplace: protocol for a stepped wedge randomised controlled pilot trial

BACKGROUND

An estimated one third of energy is consumed in the workplace. The workplace is therefore an important context in which to reduce energy consumption to tackle the high rates of overweight and obesity in the general population. Altering environmental cues for food selection and consumption-physical micro-environment or 'choice architecture' interventions-has the potential to reduce energy intake. The first aim of this pilot trial is to estimate the potential impact upon energy purchased of three such environmental cues (size of portions, packages and tableware; availability of healthier vs. less healthy options; and energy labelling) in workplace cafeterias. A second aim of this pilot trial is to examine the feasibility of recruiting eligible worksites, and identify barriers to the feasibility and acceptability of implementing the interventions in preparation for a larger trial.

METHODS

Eighteen worksite cafeterias in England will be assigned to one of three intervention groups to assess the impact on energy purchased of altering (a) portion, package and tableware size (n = 6); (b) availability of healthier options (n = 6); and (c) energy (calorie) labelling (n = 6). Using a stepped wedge design, sites will implement allocated interventions at different time periods, as randomised.

DISCUSSION

This pilot trial will examine the feasibility of recruiting eligible worksites, and the feasibility and acceptability of implementing the interventions in preparation for a larger trial. In addition, a series of linear mixed models will be used to estimate the impact of each intervention on total energy (calories) purchased per time frame of analysis (daily or weekly) controlling for the total sales/transactions adjusted for calendar time and with random effects for worksite. These analyses will allow an estimate of an effect size of each of the three proposed interventions, which will form the basis of the sample size calculations necessary for a larger trial.

TRIAL REGISTRATION

ISRCTN52923504.

Impact of bottle size on in-home consumption of sugar-sweetened beverages: a feasibility and acceptability study

Background

Consumption of sugars-sweetened beverages (SSB) increases energy intake and the risk of obesity. Large packages increase consumption of food, implying that smaller bottle sizes may help curb SSB consumption, but there is a lack of relevant evidence relating to these products. This study explores the feasibility and acceptability of conducting a randomised controlled trial to assess the impact of different bottle sizes on SSB consumption at home.

Methods

Households in Cambridge, England, which purchased at least 2 l of regular cola drinks per week, received a set amount of cola each week for four weeks, in bottles of one of four sizes (1500 ml, 1000 ml, 500 ml, or 250 ml) in random order. The total volume received consisted of a modest excess of households’ typical weekly purchasing, but was further increased for half the study households to avoid ceiling effects. Consumption was measured by recording the number of empty bottles at the end of each week. Eligible households were invited to complete a run-in period to assess levels of active participation.

Results

Thirty-seven of 111 eligible households with an interest in the study completed the run-in period. The study procedures proved feasible. The target for recruitment (n = 16 households) was exceeded. Measuring consumption was feasible: over three quarters (n = 30/37) of households returned all bottles on the majority (n = 88/101) of the study weeks completed across households. The validity of this measure was compromised by guests from outside the household who drank the study cola (n = 18/37 households on 48/101 study weeks) and consumption of the study cola outside the home. Supplying enhanced volumes of cola to nine households was associated with higher consumption (11,592 ml vs 7869 ml). The intervention and study procedures were considered acceptable. Thirteen households correctly identified the study aims.

Conclusion

The findings support the feasibility and acceptability of running a randomised controlled trial to assess the impact of presenting a fixed volume of SSB in different bottle sizes on in-home consumption. However, methods that avoid consumption being influenced by the amount of cola supplied weekly by the study and that capture out of home consumption are needed before conducting a randomised controlled trial.

Trial registration

ISRCTN14964130; Registered on 18th May, 2015.

Does Glass Size and Shape Influence Judgements of the Volume of Wine?

BACKGROUND

Judgements of volume may influence the rate of consumption of alcohol and, in turn, the amount consumed. The aim of the current study was to examine the impact of the size and shape of wine glasses on perceptions of wine volume.

METHODS

Online experiment: Participants (n = 360; recruited via Mechanical Turk) were asked to match the volume of wine in two wine glasses, specifically: 1. the Reference glass holding a fixed reference volume, and 2. the Comparison glass, for which the volume could be altered until participants perceived it matched the reference volume. One of three comparison glasses was shown in each trial: 'wider' (20% wider but same capacity); 'larger' (same width but 25% greater capacity); or 'wider-and-larger' (20% wider and 25% greater capacity). Reference volumes were 125 ml, 175 ml and 250 ml, in a fully factorial within-subjects design: 3 (comparison glass) x 3 (reference volume). Non-zero differences between the volumes with which participants filled comparison glasses and the corresponding reference volumes were identified using sign-rank tests.

RESULTS

Participants under-filled the wider glass relative to the reference glass for larger reference volumes, and over-filled the larger glass relative to the reference glass for all reference volumes. Results for the wider-and-larger glass showed a mixed pattern across reference volume. For all comparison glasses, in trials with larger reference volumes participants tended to fill the comparison glass less, relative to trials with smaller reference volumes for the same comparison glass.

CONCLUSIONS

These results are broadly consistent with people using the relative fullness of glasses to judge volume, and suggest both the shape and capacity of wine glasses may influence perceived volume. Perceptions that smaller glasses contain more than larger ones (despite containing the same volume), could slow drinking speed and overall consumption by serving standard portions in smaller glasses. This hypothesis awaits testing.

Supermarket Choice, Shopping Behavior, Socioeconomic Status, and Food Purchases

INTRODUCTION

Both SES and supermarket choice have been associated with diet quality. This study aimed to assess the contributions of supermarket choice and shopping behaviors to the healthfulness of purchases and social patterning in purchases.

METHODS

Observational panel data on purchases of fruit and vegetables and less-healthy foods/beverages from 2010 were obtained for 24,879 households, stratified by occupational social class (analyzed in 2014). Households' supermarket choice was determined by whether they ever visited market-defined high- or low-price supermarkets. Analyses also explored extent of use within supermarket choice groups. Shopping behaviors included trip frequency, trip size, and number of store chains visited.

RESULTS

Households using low-price (and not high-price) supermarkets purchased significantly lower percentages of energy from fruit and vegetables and higher percentages of energy from less-healthy foods/beverages than households using high-price (and not low-price) supermarkets. When controlling for SES and shopping behaviors, the effect of supermarket choice was reduced but remained significant for both fruit and vegetables and less-healthy foods/beverages. The extent of use of low- or high-price supermarkets had limited effects on outcomes. More-frequent trips and fewer small trips were associated with healthier purchasing for both outcomes; visiting more store chains was associated with higher percentages of energy from fruit and vegetables.

CONCLUSIONS

Although both supermarket choice and shopping behaviors are associated with healthfulness of purchases, neither appears to contribute to socioeconomic differences. Moreover, differences between supermarket environments may not be primary drivers of the relationship between supermarket choice and healthfulness of purchases.

Impact of bottle size on in-home consumption of sugar-sweetened beverages: protocol for a feasibility and acceptability study

BACKGROUND

Intake of free sugars in the population exceeds recommendations, with the largest source in the diet being sugar-sweetened beverages (SSBs). SSB consumption is linked to adverse health consequences and contributes to health inequalities, given greater consumption amongst the most deprived. One possible intervention is to reduce the available sizes of SSB packaging but there is an absence of evidence that this would reduce consumption. Based on evidence from studies targeting food consumption that people consume less when exposed to smaller package sizes, we hypothesise that presenting SSBs in smaller containers reduces consumption. We are planning a crossover randomised controlled trial to assess the impact of presenting a fixed volume of SSB in different bottle sizes on consumption at home. To reduce the uncertainties related to this trial, we propose a preliminary study to assess the feasibility and acceptability of the recruitment, allocation, measurement, retention and intervention procedures.

METHODS/DESIGN

Households which purchase at least 2 l of regular cola drinks per week and live in Cambridgeshire, UK will have a set amount of a cola SSB (based on their typical weekly purchasing of cola) delivered to their homes each week by the research team. This total amount of cola will be packaged into bottles of one of four sizes: (i) 1500 ml, (ii) 1000 ml, (iii) 500 ml or (iv) 250 ml. A crossover design will be used in which households will each receive all four of the week-long interventions (the four different bottle sizes) over time, randomised in their order of presentation. Approximately 100 eligible households will be approached to assess the proportion interested in actively participating in the study. Of those interested, 16 will be invited to continue participation.

DISCUSSION

The findings will inform the procedures for a crossover randomised controlled trial assessing the impact of presenting a fixed volume of SSB in different bottle sizes on consumption at home. The findings from such a trial are expected to provide the best estimate to date of the effect of container size on beverage consumption and inform ongoing scientific and policy discussions about the effectiveness of this intervention at reducing population intake of free sugars in beverages.

TRIAL REGISTRATION

ISRCTN14964130.

Making food labels social: The impact of colour of nutritional labels and injunctive norms on perceptions and choice of snack foods

Recent studies report that using green labels to denote healthier foods, and red to denote less healthy foods increases consumption of green- and decreases consumption of red-labelled foods. Other symbols (e.g. emoticons conveying normative approval and disapproval) could also be used to signal the healthiness and/or acceptability of consuming such products. The present study tested the combined effects of using emoticons and colours on labels amongst a nationally representative sample of the UK population (n = 955). In a 3 (emoticon expression: smiling vs. frowning vs. no emoticon) × 3 (colour label: green vs. red vs. white) ×2 (food option: chocolate bar vs. cereal bar) between-subjects experiment, participants rated the level of desirability, healthiness, tastiness, and calorific content of a snack bar they had been randomised to view. At the end they were further randomised to view one of nine possible combinations of colour and emoticon labels and asked to choose between a chocolate and a cereal bar. Regardless of label, participants rated the chocolate as tastier and more desirable when compared to the cereal bar, and the cereal bar as healthier than the chocolate bar. A series of interactions revealed that a frowning emoticon on a white background decreased perceptions of healthiness and tastiness of the cereal bar, but not the chocolate bar. In the explicit choice task selection was unaffected by label. Overall nutritional labels had limited effects on perceptions and no effects on choice of snack foods. Emoticon labels yielded stronger effects on perceptions of taste and healthiness of snacks than colour labels. Frowning emoticons may be more potent than smiling emoticons at influencing the perceived healthiness and tastiness of foods carrying health halos.

Price promotions on healthier compared with less healthy foods: a hierarchical regression analysis of the impact on sales and social patterning of responses to promotions in Great Britain

BACKGROUND

There is a growing concern, but limited evidence, that price promotions contribute to a poor diet and the social patterning of diet-related disease.

OBJECTIVE

We examined the following questions: 1) Are less-healthy foods more likely to be promoted than healthier foods? 2) Are consumers more responsive to promotions on less-healthy products? 3) Are there socioeconomic differences in food purchases in response to price promotions?

DESIGN

With the use of hierarchical regression, we analyzed data on purchases of 11,323 products within 135 food and beverage categories from 26,986 households in Great Britain during 2010. Major supermarkets operated the same price promotions in all branches. The number of stores that offered price promotions on each product for each week was used to measure the frequency of price promotions. We assessed the healthiness of each product by using a nutrient profiling (NP) model.

RESULTS

A total of 6788 products (60%) were in healthier categories and 4535 products (40%) were in less-healthy categories. There was no significant gap in the frequency of promotion by the healthiness of products neither within nor between categories. However, after we controlled for the reference price, price discount rate, and brand-specific effects, the sales uplift arising from price promotions was larger in less-healthy than in healthier categories; a 1-SD point increase in the category mean NP score, implying the category becomes less healthy, was associated with an additional 7.7-percentage point increase in sales (from 27.3% to 35.0%; P < 0.01). The magnitude of the sales uplift from promotions was larger for higher-socioeconomic status (SES) groups than for lower ones (34.6% for the high-SES group, 28.1% for the middle-SES group, and 23.1% for the low-SES group). Finally, there was no significant SES gap in the absolute volume of purchases of less-healthy foods made on promotion.

CONCLUSION

Attempts to limit promotions on less-healthy foods could improve the population diet but would be unlikely to reduce health inequalities arising from poorer diets in low-socioeconomic groups.

Why don't poor men eat fruit? Socioeconomic differences in motivations for fruit consumption

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The study examined intake, implicit and explicit liking, and perceptions of fruit.

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Lower SES males reported eating less fruit and lower implicit liking of fruit.

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Results differed for explicit liking of fruit, however, with no differences by SES.

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Social patterning was also seen in perceived satiety and value for money of fruit.

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Neither liking nor perceptions of fruit mediated social patterning of fruit intake.

Background: Those of lower socioeconomic status (SES) tend to have less healthy diets than those of higher SES. This study aimed to assess whether differences in motivations for particular foods might contribute to socioeconomic differences in consumption. Methods: Participants (n = 732) rated their frequency of consumption and explicit liking of fruit, cake and cheese. They reported eating motivations (e.g., health, hunger, price) and related attributes of the investigated foods (healthiness, expected satiety, value for money). Participants were randomly assigned to an implicit liking task (Single Category Implicit Association Task) for one food category. Analyses were conducted separately for different SES measures (income, education, occupational group). Results: Lower SES and male participants reported eating less fruit, but no SES differences were found for cheese or cake. Analyses therefore focused on fruit. In implicit liking analyses, results (for income and education) reflected patterning in consumption, with lower SES and male participants liking fruit less. In explicit liking analyses, no differences were found by SES. Higher SES participants (all indicators) were more likely to report health and weight control and less likely report price as motivators of food choices. For perceptions of fruit, no SES-based differences were found in healthiness whilst significant interactions (but not main effects) were found (for income and education) for expected satiety and value for money. Neither liking nor perceptions of fruit were found to mediate the relationship between SES and frequency of fruit consumption. Conclusions: There is evidence for social patterning in food motivation, but differences are modified by the choice of implicit or explicit measures. Further work should clarify the extent to which these motivations may be contributing to the social and gender patterning in diet.

Impact on alcohol purchasing of a ban on multi-buy promotions: a quasi-experimental evaluation comparing Scotland with England and Wales

AIMS

To evaluate the impact of the 2011 Scottish ban on multi-buy promotions of alcohol in retail stores.

DESIGN AND SETTING

Difference-in-differences analysis was used to estimate the impact of the ban on the volume of alcohol purchased by Scottish households, compared with those in England and Wales, between January 2010 and June 2012.

PARTICIPANTS

A total of 22 356 households in Scotland, England and Wales.

MEASUREMENTS

Records of alcohol purchasing from each of four categories (beer and cider, wine, spirits and flavoured alcoholic beverages), as well as total volume of pure alcohol purchased.

FINDINGS

Controlling for general time trends and household heterogeneity, there was no significant effect of the multi-buy ban in Scotland on volume of alcohol purchased either for the whole population or for individual socio-economic groups. There was also no significant effect on those who were large pre-ban purchasers of alcohol. Most multi-buys were for beer and cider or for wine. The frequency of shopping trips involving beer and cider purchases increased by 9.2% following the ban (P < 0.01), while the number of products purchased on each trip decreased by 8.1% (P < 0.01). For wine, however, these effects were not significant.

CONCLUSIONS

Banning multi-buy promotions for alcohol in Scotland did not reduce alcohol purchasing in the short term. Wider regulation of price promotion and price may be needed to achieve this.

Sales impact of displaying alcoholic and non-alcoholic beverages in end-of-aisle locations: an observational study

In-store product placement is perceived to be a factor underpinning impulsive food purchasing but empirical evidence is limited. In this study we present the first in-depth estimate of the effect of end-of-aisle display on sales, focussing on alcohol. Data on store layout and product-level sales during 2010-11 were obtained for one UK grocery store, comprising detailed information on shelf space, price, price promotion and weekly sales volume in three alcohol categories (beer, wine, spirits) and three non-alcohol categories (carbonated drinks, coffee, tea). Multiple regression techniques were used to estimate the effect of end-of-aisle display on sales, controlling for price, price promotion, and the number of display locations for each product. End-of-aisle display increased sales volumes in all three alcohol categories: by 23.2% (p = 0.005) for beer, 33.6% (p < 0.001) for wine, and 46.1% (p < 0.001) for spirits, and for three non-alcohol beverage categories: by 51.7% (p < 0.001) for carbonated drinks, 73.5% (p < 0.001) for coffee, and 113.8% (p < 0.001) for tea. The effect size was equivalent to a decrease in price of between 4% and 9% per volume for alcohol categories, and a decrease in price of between 22% and 62% per volume for non-alcohol categories. End-of-aisle displays appear to have a large impact on sales of alcohol and non-alcoholic beverages. Restricting the use of aisle ends for alcohol and other less healthy products might be a promising option to encourage healthier in-store purchases, without affecting availability or cost of products.

Impact of plain packaging of tobacco products on smoking in adults and children: an elicitation of international experts' estimates

BACKGROUND

Governments sometimes face important decisions in the absence of direct evidence. In these cases, expert elicitation methods can be used to quantify uncertainty. We report the results of an expert elicitation study regarding the likely impact on smoking rates in adults and children of plain packaging of tobacco products.

METHODS

Thirty-three tobacco control experts were recruited from the UK (n = 14), Australasia (n = 12) and North America (n = 7). Experts' estimates were individually elicited via telephone interviews, and then linearly pooled. Elicited estimates consisted of (1) the most likely, (2) the highest possible, and (3) the lowest possible value for the percentage of (a) adult smokers and (b) children trying smoking, two years after the introduction of plain packaging (all other things being constant) in a target country in the expert's region of residence.

RESULTS

The median estimate for the impact on adult smoking prevalence was a 1 percentage point decline (99% range 2.25 to 0), and for the percentage of children trying smoking was a 3 percentage point decline (99% range 6.1 to 0), the latter estimated impact being larger than the former (P < 0.001, sign test). There were no differences in either estimate by region (I2: Adults: 0; Children: 0) but there was considerable variability between experts' estimates within regions (I2: Adults: 0.91; Children: 0.89).

CONCLUSIONS

In the absence of direct evidence for the impact of introducing plain packaging on smoking rates in adults and children, this study shows that tobacco control experts felt the most likely outcomes would be a reduction in smoking prevalence in adults, and a greater reduction in the numbers of children trying smoking, although there was substantial variability in the estimated size of these impacts. No experts judged an increase in smoking as a likely outcome.

Using co-occurrence to evaluate belief coherence in a large non clinical sample

Much of the recent neuropsychological literature on false beliefs (delusions) has tended to focus on individual or single beliefs, with few studies actually investigating the relationship or co-occurrence between different types of co-existing beliefs. Quine and Ullian proposed the hypothesis that our beliefs form an interconnected web in which the beliefs that make up that system must somehow “cohere” with one another and avoid cognitive dissonance. As such beliefs are unlikely to be encapsulated (i.e., exist in isolation from other beliefs). The aim of this preliminary study was to empirically evaluate the probability of belief co-occurrence as one indicator of coherence in a large sample of subjects involving three different thematic sets of beliefs (delusion-like, paranormal & religious, and societal/cultural). Results showed that the degree of belief co-endorsement between beliefs within thematic groupings was greater than random occurrence, lending support to Quine and Ullian’s coherentist account. Some associations, however, were relatively weak, providing for well-established examples of cognitive dissonance.

Prevalence and correlates of anomalous experiences in a large non-clinical sample

BACKGROUND

Anomalous experiences occur in many psychiatric conditions, but are also reported by non-patients. Given the continuum account of psychiatric symptoms and reports of dissociation between delusions and anomalous experiences, we predicted that anomalous experiences in a large non-clinical sample would (1) associate with delusion-like beliefs but not with socio-cultural beliefs and (2) that anomalous experiences would also show examples of dissociation with anomalous beliefs. A particular focus was the association between beliefs and experiences theoretically predicted to co-occur in Capgras syndrome.

METHODS

The study examined the distribution and correlates of differential levels of self-reported anomalous experience in a British sample of 1,000 individuals.

RESULTS

Anomalous experiences were found to be relatively common in the general population and were reported (occurring sometimes/often) by 48% of the sample. Being female and endorsing a non-Christian religion were the only two demographic factors related to higher experience scores. Significant relationships were found between anomalous experiences and anomalous beliefs (i.e., delusion-like and paranormal/religious), but not general societal beliefs. Dissociations between anomalous experiences and anomalous beliefs also were present but not common. No significant relationship was found between Capgras-type beliefs and experiences.

CONCLUSIONS

This large scale study demonstrated significant association between anomalous experiences and anomalous beliefs in the general population. The relationship was not, however present in all cases similar to cases reported in the clinical literature.