Socioeconomic Position and the Impact of Increasing Availability of Lower Energy Meals vs. Menu Energy Labelling on Food Choice in Virtual Full-service Restaurants: Two Randomized Control Trials
Phase: NA
Conditions: Nutrition Poor, Obesity, Diet, Healthy, Food Selection
Sponsor: University of Liverpool

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STUDY PROTOCOL. . NCT (Uni.Liverpool reference): 4612WP1B2b 
Study title: Socioeconomic status and the effect of information-based versus structural interventions 
on food choices at US restaurants: an online randomized experiment 
Short title: US Restaurant Study 
Investigators: Dr Lucile Marty 
Dr Andrew Jones 
Dr Eric Robinson 
Funder: European Research Council 
TABLE OF CONTENT 
 
1. 
BACKGROUND AND RATIONALE .................................................................................................... 2 
2. 
OBJECTIVES, OUTCOMES MEASURES AND HYPOTHESES ............................................................. 2 
3. 
EXPERIMENTAL DESIGN ................................................................................................................. 3 
4. 
PARTICIPANTS AND RECRUITMENT ............................................................................................... 3 
4.1. 
Recruitment ............................................................................................................................ 3 
4.2. 
Inclusion criteria ..................................................................................................................... 3 
4.3. 
Exclusion criteria .................................................................................................................... 3 
5. 
METHODS ....................................................................................................................................... 4 
5.1. 
Meal choice task ..................................................................................................................... 4 
5.2. 
Measures of socioeconomic status ........................................................................................ 6 
5.3. 
Measure of health motivation ............................................................................................... 6 
6. 
STUDY FLOW ................................................................................................................................... 6 
7. 
STATISTICAL ANALYSIS ................................................................................................................... 7 
7.1. 
Participant’s characteristics ................................................................................................... 7 
7.2. 
Variables description .............................................................................................................. 7 
7.3. 
Missing data ........................................................................................................................... 9 
7.4. 
Main analyses ......................................................................................................................... 9 
7.6. 
Sample size ........................................................................................................................... 11 
8. 
REFERENCES .................................................................................................................................. 12 
9. 
APPENDIX A: PROCESS OF ORDERING MAINS ITEMS ON THE MENUS ...................................... 15 
10. 
APPENDIX B: GLOBAL CUISINE SURVEY SUMMARY ................................................................ 17 
11. 
APPENDIX C: AUDIENCE (PROLIFIC WEBSITE).......................................................................... 18 
12. 
APPENDIX D: RECRUITMENT TEXT ........................................................................................... 19 
13. 
APPENDIX E: INFORMATION PAGE .......................................................................................... 20 
14. 
APPENDIX F: CONSENT PAGE ................................................................................................... 23 

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15. 
APPENDIX G: BASELINE QUESTIONNAIRE................................................................................ 25 
16. 
APPENDIX H: MEAL CHOICE TASK INSTRUCTION .................................................................... 28 
17. 
APPENDIX I: SINGLE ITEM FOOD CHOICE QUESTIONNAIRE .................................................... 29 
18. 
APPENDIX J: DEBRIEFING ......................................................................................................... 30 
19. 
APPENDIX K: DEBRIEFING TEXT ............................................................................................... 32 
 
1. BACKGROUND AND RATIONALE 
A substantial contributor to social inequalities in health is diet [1], [2]. The dietary quality of people 
of lower socioeconomic status (SES) is poorer than that of people of higher SES [3], [4] and 
particularly rich in energy [5], [6] which likely contributes to the development of obesity and of a 
larger disease burden among people of lower SES [7]. 
Eating out of home has been associated to higher energy intake, weight gain and obesity [8], [9]. Yet, 
the popularity and availability of ready-to-eat meals have risen considerably over the last few 
decades [10], [11]. In this context, there is an increasing interest in interventions that aim at 
reducing the energy intake from food prepared out-of-home [12]–[14]. 
Information-based nutrition interventions (e.g., energy labelling on food menus) are one of the most 
common approaches to influence food choices [15], [16]. However, information-based interventions 
have been suggested to be less effective among people of lower compared to higher SES [17], [18] 
and therefore they may inadvertently widen inequalities in diet. Structural interventions that target 
core features of the food environment (e.g., increasing the availability of lower energy foods) are an 
alternative intervention approach do not depend on a sustained ‘agentic’ individual response [15], 
[19]. 
Information-based interventions typically rely on people understanding health consequences of 
what they eat and being motivated by health in their food choices [19]. Yet, health may be a less 
influential motive for food choice among people of lower SES [20]. Thus, SES based differences in 
food choice motives and health literacy may explain why information-based interventions would be 
less effective among people of lower vs. higher SES. 
Moreover, the overall effect of energy labelling is small or unclear, as depicted in recent systematic 
reviews [21]–[23]. A possibility that has not been tested to date is that the effect of kcal labelling on 
purchasing behaviour is dependent on peoples’ existing knowledge about the energy content of 
menu items, whereby energy labelling is most effective when people are making food choices from 
unfamiliar menus and therefore are less able to distinguish from the lower and high energy menu 
items. 
 
2. OBJECTIVES, OUTCOMES MEASURES AND HYPOTHESES 
OBJECTIVES 
OUTCOME MEASURES 
HYPOTHESES 
Primary objective 
 
To examine the effect that an 
information-based 
intervention (energy labelling) 
 
 
Energy (kcal) of the ordered 
meal. 
 
 
An increased availability of 
lower energy menu options 
will result in a decrease in total 

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and a structural intervention 
(increased availability of lower 
kcals options) have on kcals 
ordered in a hypothetical meal 
ordering task among 
participants of lower and 
higher SES. 
 
 
energy ordered among both 
participants of lower and 
higher SES. 
However, energy labelling may 
exert a stronger effect on 
energy ordered among 
participants of higher vs. lower 
SES. 
Secondary objectives 
 
To examine the reasons why 
the effects that energy 
labelling have on kcals ordered 
may vary based on a 
participants’ SES. 
 
 
 
 
To examine the effect of 
labelling on familiar and 
unfamiliar cuisines menus. 
 
 
Health motivation in food 
choices (questionnaire score). 
 
 
 
 
 
 
 
Energy (kcal) of the ordered 
meals for familiar and 
unfamiliar cuisines.  
 
 
The participants of higher SES 
will be more motivated by 
health in their food choices 
than participants of lower SES, 
which will mediate the 
relationship between SES and 
the effect of energy labelling 
on the total energy ordered. 
 
Energy labelling will have a 
greater effect for unfamiliar 
compared to familiar cuisines. 
 
3. EXPERIMENTAL DESIGN 
Participants will be enrolled in an online survey and make hypothetical menu choices. Participants 
will be randomized into a mixed-design experiment with 2x2 between-subjects conditions with 
factors of kcal labelling (absent vs. present) and availability (baseline availability of main dishes with 
≤600kcals vs. higher availability of main dishes with ≤600kcals) and 6 repeated measures (3 familiar 
and 3 unfamiliar menus). 
4. PARTICIPANTS AND RECRUITMENT 
 
4.1. Recruitment 
Participants will be recruited through an online recruitment panel (Prolific) in which participants are 
compensated proportionate to the time it takes to complete the online study (≈ $6/hour reward 
participants). Participants’ recruitment will be stratified by gender (50% male, 50% female), student 
status (8% yes and 92% no) [24] and highest achieved education level (10% less than high school, 
30% high school completion, 30% some college or associate's degree, 20% bachelor’s degree, 10% 
advanced degree) to be representative of US adults [25]. 
4.2. Inclusion criteria 
 
• 
US residents, age ≥ 18 
• 
Fluent in English 
• 
Have access to a computer and Internet 
 
4.3. Exclusion criteria 

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• 
Having any dietary restriction: 
o Vegetarian 
o Vegan 
o Gluten-free 
o Sugar-free 
o Diary/lactose-free 
o Food allergy (e.g. milk, eggs, nut, wheat, fish, etc.) 
 
5. METHODS 
 
5.1. Meal choice task 
Procedure 
Participants will be asked to select the meal options they would be most likely to choose from six 
different dining out scenarios. Participants will be randomly allocated to one of the following group: 
o baseline availability & no energy labelling (C: control); 
o baseline availability & energy labelling (CL: kcal labelling); 
o increased availability of lower energy options & no energy labelling (A: availability); 
o increased availability of lower energy options & energy labelling (AL: availability and 
kcal labelling). 
For each dining out scenario participants will be asked to imagine that they are eating out with 
friends for dinner at a […] style restaurant. They will first be shown an image of the restaurant from 
the outside, before being shown an image of the inside of the restaurant and then the menu. 
Participants will be asked to make their main dish selection from a menu including 10 main dishes 
options. 
In order to examine whether participants are more likely to order ‘additional’ food as a result of 
ordering a lower energy option, after selecting their main dish option participants will be shown a 
‘sides’ section of the menu displaying 5 sides dependent on dining out scenario. Participants will be 
asked whether they would order an additional side with their meal and if they select ‘yes’, they will 
select their side. The same options will be shown in all conditions, although in the no energy 
labelling conditions (C and A) there will be no kcal information next to menu options and in the 
energy labelling conditions (CL and AL) there will be kcal information next to each menu options. On 
the next page, this will be repeated for the dessert menu. The dessert menu will display 5 dessert 
options dependent on dining out scenario. As described for the ‘sides’ section, the same dessert 
options will be shown in all conditions and kcal information will be displayed in the energy labelling 
conditions (CL and AL). 
The six dining out scenarios will be randomised in order. Additionally, the order of the dishes in each 
main menu was counterbalanced as explained in Appendix A. For the sides and desserts menus, two 
variants with different random order of the items will be created for each condition. 
Menus 
The design of the restaurant menus will be based on menus from existing US restaurants. In a recent 
study, 1,184 American adults were asked which of 34 national cuisines they had tried and whether 

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they liked or disliked them [26]; results are summarised in Appendix B. Based on these results we 
selected three familiar (tried by at least 90% of US people: American, Mexican and Italian cuisines) 
and three unfamiliar cuisines (never tried by approximately 50% of US people: Lebanese, Peruvian, 
Moroccan cuisines) for American people. Using the online menus of US restaurants offering the 
selected cuisines, we will then create sample menus for the six distinct restaurant cuisines, each 
consisting of 10 main dishes and a selection of between 5 sides and 5 desserts (including actual food 
names, description and prices). 
For familiar cuisines, the menu-model restaurants will be US popular chain restaurants (>800 outlets 
across the country); for unfamiliar cuisines, they will be US restaurants offering these specific types 
of cuisines that will be chosen by searching for restaurants in large US cities: New-York, Los Angeles, 
Chicago, Houston (using Yelp, Tripadvisor). All the food items (and their description) included in the 
experimental menus will be based on existing US restaurants. Because kcal labelling is only 
mandatory for restaurant chains in the US, we will use external sources to calculate the energy 
content per 100g of the menu options available for unfamiliar cuisines (e.g., online recipes, national 
food composition databases). All the six menus will offer a similar range of main options in terms of 
energy content (i.e., similar min, median and max). 
Interventions 
LE options are main dishes ≤600 kcal because meals ≤600 kcal comply with the dietary 
recommendation for US adults (i.e., on average 2,000 kcal per day) assuming an energy repartition 
pattern of three main meal occasions, each accounting for 20–35 % of daily energy intake, and 1–2 
snacking occasions, each accounting for 5–10 % of daily energy intake [27]. 
In the baseline availability conditions (C and CL) 1/10 main dishes on the menus will be 600 kcal or 
less and 9/10 will exceed 600 kcal. In the increased availability of lower energy options conditions (A 
and AL), the proportion of main dishes ≤ 600 kcal will be increased to 5/10 by replacing four of the > 
600 kcal main dishes from the baseline availability conditions with lower energy main dishes, whilst 
holding the price of replaced menu items the same. The menu items with the highest and the lowest 
energy content will remain the same in order to ensure the range of energy is consistent across 
conditions. The difference in the mean energy content of the menus items between C/CL and A/AL 
conditions will be approx. the same for familiar and unfamiliar menus. 
In the energy labelling conditions (L and AL) energy in kcal will be added next to each menu option 
and reference information on energy requirements will be displayed. The energy labelling format 
will be in line with the mandatory menu labelling policy published by the US Food and Drug 
Administration [28], which requires restaurants to: 
• 
Disclose calories for standard menu items listed on menus and menu boards: 
o Calorie labelling is placed on the menu adjacent to the name or the price of the 
menu item in a manner in close proximity and clearly associated with the menu 
item; 
• 
Include on menus a succinct statement concerning suggested caloric intake and a statement 
that additional nutrition information is available upon request: 
o The succinct statement ‘2,000 calories a day is used for general nutrition advice, but 
calorie needs vary’ must appear on the bottom of menu boards and at the bottom of 
each page of multi-page menus; 

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o The statement of availability ‘Additional nutrition information available upon 
request’ must appear on the bottom of the first page of a menu that lists standard 
menu items and at the bottom of the menu board 
o They may be on the individual sign adjacent to the food itself, or on a separate, 
larger sign in close proximity to the food. The customer must be able to easily read 
the sign when making a selection. 
In the no energy labelling conditions (C and A) there will be no kcal information next to menu 
options. 
5.2. Measures of socioeconomic status 
The socioeconomic status is a multi-faceted concept. Four measures of socioeconomic status will be 
included. Participants will be asked to report: 
- 
their highest educational qualification; 
- 
their number of years in higher education; 
- 
their current employment status and main job title; 
- 
their household income and their household composition; 
- 
a subjective measure of their socioeconomic status using the MacArthur Scale of Subjective 
Social Status (SSS) [29]. 
 
5.3. Measure of health motivation 
The Food Choice Questionnaire, developed by Steptoe et al. 1995 [30], measures the motives 
related to food choice, including health. We will use a short version of this questionnaire, the single-
item Food Choice Questionnaire recently developed by Onwezen et al. 2019 [31]. 
 
6. STUDY FLOW 
RECRUITMENT 
(Prolific) 
▪ 
Predefined screening questions of Prolific website will be used to 
target the sample (Appendix C) 
▪ 
Participants who meet the inclusion/exclusion criteria will be e-
mailed by Prolific and/or offered to complete our study on their 
Prolific account (Appendix D) 
▪ 
Eligible participants who want to take part on the study will click 
on the start button and be redirected to our study website 
(Qualtrics) 
INFORMED CONSENT 
▪ 
Participants will read the information sheet (Appendix E) 
▪ 
Participants who want to proceed will tick a consent box 
(Appendix F) 
RANDOMISATION 
▪ 
When starting the study, participants will be equally randomized 
to the four experimental conditions 
BASELINE 
ASSESSMENTS 
▪ 
Participants will complete a baseline questionnaire on 
demographics (Appendix G) 
MEAL CHOICE TASK 
▪ 
Instructions will be displayed (Appendix H) 
▪ 
Dining-out scenarios will be displayed in randomised order 
▪ 
For each dining out scenario, participants will be asked to choose 
their main meal and whether they would like to order a side and 
a dessert. 

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Control 
condition 
Energy labelling 
condition 
Low energy 
increased 
availability 
condition 
Low energy 
increased 
availability and 
energy labelling 
condition 
HEALTH MOTIVATION  
▪ 
Single-item Food Choice Questionnaire (Appendix I) 
DEBRIEFING 
▪ 
Aim guessing in an open-ended response format 
▪ 
Insight on the participants’ perception of the meal ordering task 
(Appendix J) 
▪ 
Text to tell the participants what the study was about (Appendix 
K) 
DATA MANAGEMENT 
▪ 
The result files will contain: 
o Participant unique ID 
o Experimental condition participant is directed to 
o Food choices 
o Answers to questionnaires 
 
7. STATISTICAL ANALYSIS 
All statistical analyses will be performed using SAS version 9.3 (SAS Institute, Inc., 2012 SAS® 9.3. 
Cary, NC). The level of significance will be set at p < 0.05. Linear mixed models will be fitted with 
PROC MIXED. 
7.1. Participant’s characteristics 
A table will present the baseline characteristics by condition group and overall. The table will include 
gender, age, ethnic group, proportion of students, highest educational qualification, years in higher 
education, household income, subjective socioeconomic status, BMI, dieting status, dining-out 
frequency. Continuous variables will be summarised using means and standard deviations. 
Categorical variables will be summarised using counts and percentages. 
7.2. Variables description 
Primary outcome 
The main outcome variable is the energy of the main selected in each dining out scenario in kcal. 
Secondary outcome 
From the meal choice task: 
We will also calculate the total energy of the selected meal. It will be calculated by summing the kcal 
of the selected main, side and dessert. 
From the debriefing questionnaire: 
- 
Validity of menu design (item 2) 
- 
Validity of food offer (items 4 and 5) 
- 
Kcal influence (item 3) 
Answers to all the items will be coded as: 1 = Strongly disagree; 2 = Disagree; 3 = Slightly disagree; 4 
= Neither agree or disagree; 5 = Slightly agree; 6 = Agree; 7 = Strongly agree. 

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Internal dimension consistency of the items measuring validity of food offer (for each cuisine) will be 
assessed by calculating McDonald’s ω for each, which is an alternative to Cronbach’s α when the 
total test scores are normally distributed (i.e., all items are normally distributed) [32]. If adequate 
consistency is reached (ω ≥ 0.7), validity of food offer (for each cuisine) score will be calculated as the 
mean of the two items constituting the dimension. In the case where internal consistency is not 
acceptable, we will run analyses separately on individual items. 
Independent variables 
SES 
Level of education 
- 
Highest educational qualification will be coded from 1 = less than high school; 2 = high 
school completion; 3 = some college or associate degree; 4 = bachelorˈs degree; 5 = masterˈs 
degree; 6 = doctoral or professional degree [33], [34] and as a binary variable as lower 
(values: 1 and 2) or higher (values: 3, 4, 5 and 6). 
- 
Years in higher education, as a continuous variable. 
Assuming that the two education variables are significantly correlated (tested using Pearson’s r) we 
will z-score the two variables and create an average of the two to form a composite score called 
‘level of education’. 
Health motivation 
The health motivation score will be coded from 1 to 7 and correspond to the responses at the first 
and ninth items of the Single-item Food choice Questionnaire: “It is important to me that the food I 
eat on a typical day is healthy” and “It is important to me that the food I eat on a typical day helps 
me control my weight”: 1 = Not at all important; 2 = Not important; 3 = Not very important; 4 = 
Neutral; 5 = Slightly important; 6 = Important; 7 = Very important. 
Cuisine familiarity 
- 
Familiarity condition: Binary variable based on the experimental design: 0 for unfamiliar 
cuisines and 1 for familiar cuisines 
- 
Familiarity score: Ordinal variable based participants answer for each cuisine to the question 
“Have you ever tried [6 cuisines]?” coded as 1: Never tried; 2: Not in the last year; 3:Less 
than once per month; 4: 1-3 times per month; 5: 1-2 times per week; 6: 3 times per week or 
more 
Other variables 
Household income: To be consistent with US census data [35], participants will report their annual 
household income before tax to the nearest $1000. 
Subjective SES: The measure of the Subjective Social Status using the MacArthur Scale will be coded 
from 1 to 10. 
BMI will be calculated as weight (kg) / Height (m2). BMI data only will be trimmed for implausible 
values: BMI>10 or BMI<60 [36]. 
Aim guessing: Participants who identify the aim of the study as being to examine the influence of 
energy labelling or increased availability of lower energy food items on food choices will be coded as 

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being aware of the study aims. Responses will be independently coded by two researchers, with 
discrepancies in coding decisions resolved by a third researcher. 
7.3. Missing data 
We do not anticipate missing data on the primary outcome and dependant variables because the 
online study will not allow missing answers. Data from participants who start but not finish the study 
will not be analysed. Submissions of participants who fail the attention checks or do not pass 
eligibility criteria will not be analysed. Any a posteriori withdrawal will be reported and reasons for 
withdrawal will be documented (e.g., incorrect answers, technical problems). 
7.4. Main analyses 
The measure of SES used in our primary analysis will be the highest educational qualification 
(categorical variable: lower vs. higher) because previous research showed that people with college 
education were more likely to use kcal labels at restaurants [37]. The measure of health motivation 
will be the response to the first item from the Single-item Food choice Questionnaire: “It is 
important to me that the food I eat on a typical day is healthy”, i.e., importance of healthiness. 
First, we will examine whether our manipulation of familiarity is valid by examining the proportion of 
participants that are familiar / unfamiliar with each cuisine menu type (i.e. we expect >75% of 
participants to be familiar with our chosen ‘familiar’ cuisines and <25% of participants to be familiar 
with our ‘unfamiliar’ cuisines). We will also report the mean and SD of the familiarity score for each 
cuisine. 
A linear mixed model will be used to test the effect of labelling (categorical, between-subject), 
availability (categorical, between-subject), highest educational qualification (categorical, between-
subject), familiarity (categorical, within-subject) and labelling*highest educational qualification, 
availability*highest educational qualification, labelling*familiarity, availability*familiarity, 
interactions on energy of the main for the six dining out scenario. A random effect of participant will 
be added by using an unstructured covariance structure to account for correlation between 
repeated ordering by the same participant. 
If any interactions with familiarity are significant, analysis will be stratified by familiarity and two 
linear mixed models will be fitted to examine the effect of labelling, availability, highest educational 
qualification and labelling*highest educational qualification, availability* highest educational 
qualification interactions on energy of the main for familiar and unfamiliar cuisines with participant 
effect as random to account for correlation between repeated ordering by the same participant for 
familiar and unfamiliar cuisines. 
If the above analyses reveals a significant interaction between labelling or availability condition and 
highest educational qualification on energy of the main, analysis will be stratified by highest 
educational qualification (lower vs. higher) and two linear mixed models will be fitted to examine the 
effect of labelling and availability on energy of the main for lower and higher educational 
qualifications. 
Sensitivity analyses 
Sensitivity analyses will be conducted to examine whether the pattern of results from the main 
analyses differ after excluding participants guessing the aims of the study. 
We will also repeat the main analysis substituting the categorical variable highest educational 
qualification by the composite variable level of education as a continuous covariate. 

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We will report whether sensitivity analyses result in deviations from the pattern of significance to 
the main analyses (i.e., any significant differences between conditions becoming not significant, and 
vice versa). 
7.5. Secondary analyses 
Moderated mediation analysis of health motivation 
If the main analyses suggest that highest educational qualification moderates the effect of labelling 
or availability on energy of the main (i.e., the labelling* highest educational qualification or 
availability* highest educational qualification interaction is significant), moderated mediation 
analyses will be performed in order to examine the extent to which health motivation (HM) 
(healthiness motivation and weight control motivation) mediates the effect of highest educational 
qualification on energy of the main with and without labelling. 
If the main analysis reveals any significant interactions between labelling or availability and 
familiarity, then repeated ordering will be aggregated at participant level by calculating the average 
energy of the mains for familiar and unfamiliar cuisines separately. If the main analysis reveals no 
interaction between labelling or availability and familiarity, then repeated ordering will be 
aggregated at participant level by calculating the average energy of the mains for all cuisines. 
Conceptual diagram example (labelling): 
Statistical diagram example (labelling): 
 
 
 
 
 
 
 
Conditional indirect effect of highest educational qualification on the average energy of the mains 
through HM = a(b1+ b2labelling).  
The moderated mediation will be tested by estimating the conditional indirect effect of level of 
education on the energy of the main through HM for labelling and no labelling conditions (resp. the 
increased and baseline availability conditions) and testing the conditional indirect effect for those 
conditions using bias-corrected bootstrap. We will use the PROCESS macro (Model 15) on SAS 
version 9.3 that provides asymmetric bias-corrected bootstrap confidence intervals for inference 
about the conditional indirect effects using 5,000 bootstrap samples [38]. Moderated mediation will 
be tested by determining whether or not the confidence intervals contain zero. 
Debriefing questionnaire 
We will finally explore whether the restaurants menus are valid and the extent to which participants 
reported using kcal information when making food choices. Responses to the debriefing 
questionnaire will be analysed: 

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- 
We will describe the responses to each item (mean, SD, % agree [5, 6, 7], % disagree [1, 2, 
3]) in the overall sample to characterise validity of menu design, validity of food offer, kcal 
influence. 
- 
Three linear mixed models will be used to test the effect of labelling, availability, familiarity 
and highest educational level on the three dimensions of the debriefing questionnaire (a) 
validity of menu design, (b) validity of food offer, and (c) kcal influence to investigate 
whether the responses differ across experimental conditions and SES. 
To account for multiple testing the alpha level for secondary analyses will be set at p = 0.01. 
7.6. Sample size 
The best available evidence of the effect of kcal labelling on kcal ordered at restaurants is the meta-
analysis of Crockett et al. 2018. The authors analysed the effects of 3 RCTs testing energy labelling in 
restaurants [21]. They demonstrated a statistically significant reduction of 47 kcal in energy 
purchased when menus were labelled. The weighted average kcal ordered in the no label condition 
was 706 kcal1. These results suggest that we could expect a 7% energy reduction in the labelling 
condition compare to the control condition. Previous studies examining the effect of an increased 
availability of lower-energy products on food selection tend to produce similar or larger effects than 
kcal labelling tends to [39], [40]. In a previous trial we ran at virtual fast food restaurants 
(osf.io/ajcr6), we found a between-subject variance of 47,224 for kcal ordered (SD = 217.3). 
In a two-level mixed model, including 6 observations per participant at level 1 and estimating a level 
1 and level 2 variance of 47,244 for energy of the main, a sample size of 1,000 participants with α = 
0.05 allows to detect 2% energy reduction and above at power = 0.93 due to labelling and/or 
availability, an additional 2% energy reduction (or above) in participants of higher educational 
qualification at power = 0.81 due to an interaction between labelling and highest educational 
qualification and/or an interaction between availability and highest educational qualification, an 
additional 2% energy reduction (or above) for unfamiliar menus at power = 0.86 due to an 
interaction between labelling and familiarity and/or an interaction between availability and 
familiarity (MLPowSim) [41]. 
To observe a mediated effect of SES through health motivation 
Based on existing literature we hypothesise that the relationship between SES and food choice 
motives will be small-to-medium in size [42].Moreover, in a previous trial we ran at virtual fast food 
restaurants (osf.io/ajcr6), we found small-to-medium correlation between level of education and 
healthiness motivation (r=0.17) and small-to-medium correlation between healthiness motivation 
and kcal ordered (r=-0.25). Empirical estimates of sample sizes needed for 0.8 power in mediation 
analyses indicate that samples of ≈ 380 are sufficient to detect mediation through pathways that are 
small and small-to-medium in statistical size using bias-corrected bootstrap tests [43]. Thus, a 
sample of 1,000 participants (i.e., 580 per labelling or availability condition) allow for adequate 
power in our planned moderated mediation analysis. 
We will recruit a sample of 1,200 participants (who start the study) to account for potential data loss 
due to drop outs and failed quality controls (approx. 20%) resulting in a minimum sample of 1,000 
                                                          
1 Ellison 2013 [44]; no label: 765 (368) kcal; n=138 
Ellison 2014 [45]; no label: 746 (368) kcal; n=1532 
VanEpps 2016 [46]; no label: 605 (223) kcal; n=207 

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participants for analyses. However, if we experience a greater loss of data than expected, we will 
continue to recruit participants until we achieve the required sample size of 1,000 participants. 
 
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a joint WHO/FAO expert consultation,” Geneva, Switzerland, 2003. 
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C. Lachat, E. Nago, R. Verstraeten, D. Roberfroid, J. Van Camp, and P. Kolsteren, “Eating out of 
home and its association with dietary intake: A systematic review of the evidence,” Obes. 
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R. Rosenheck, “Fast food consumption and increased caloric intake: A systematic review of a 
trajectory towards weight gain and obesity risk,” Obes. Rev., vol. 9, no. 6, pp. 535–547, 2008. 
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J. Adams et al., “Frequency and socio-demographic correlates of eating meals out and take-
away meals at home: Cross-sectional analysis of the UK national diet and nutrition survey, 
waves 1-4 (2008-12),” Int. J. Behav. Nutr. Phys. Act., vol. 12, no. 1, pp. 1–9, 2015. 
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M. Riley, “Marketing Eating Out: The Influence of Social Culture and Innovation,” Br. Food J., 
vol. 96, no. 10, pp. 15–18, 1994. 
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Secretary of State for Health, “Healthy Lives , Healthy People : Our strategy for public health 
in England,” 2010. 
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B. M. Popkin, “The Public Health Implications of Fast-Food Menu Labeling,” Am. J. Prev. Med., 
vol. 43, no. 5, pp. 569–570, 2012. 
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F. C. Hillier-Brown et al., “A description of interventions promoting healthier ready-to-eat 
meals (to eat in, to take away, or to be delivered) sold by specific food outlets in England: A 
systematic mapping and evidence synthesis,” BMC Public Health, vol. 17, no. 1, pp. 1–17, 
2017. 
[15] 
S. Capewell and A. Capewell, “An effectiveness hierarchy of preventive interventions: 
Neglected paradigm or self-evident truth?,” J. Public Heal. (United Kingdom), vol. 40, no. 2, 
pp. 350–358, 2017. 

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[16] 
T. R. Frieden, “A framework for public health action: The health impact pyramid,” Am. J. 
Public Health, vol. 100, no. 4, pp. 590–595, 2010. 
[17] 
D. Sarink et al., “The impact of menu energy labelling across socioeconomic groups: A 
systematic review,” Appetite, vol. 99, pp. 59–75, 2016. 
[18] 
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interventions according to socioeconomic position: A systematic review,” Obes. Rev., vol. 15, 
no. 7, pp. 541–554, 2014. 
[19] 
J. Adams, O. Mytton, M. White, and P. Monsivais, “Why Are Some Population Interventions 
for Diet and Obesity More Equitable and Effective Than Others? The Role of Individual 
Agency,” PLoS Med., vol. 13, no. 4, pp. 1–7, 2016. 
[20] 
G. V. Pepper and D. Nettle, “The behavioural constellation of deprivation: causes and 
consequences,” Behav. Brain Sci., no. 2017, pp. 1–72, 2017. 
[21] 
R. A. Crockett et al., “Nutritional labelling for healthier food or non-alcoholic drink purchasing 
and consumption,” Cochrane Database Syst. Rev., vol. 2018, no. 2, 2018. 
[22] 
S. N. Bleich et al., “A Systematic Review of Calorie Labeling and Modified Calorie Labeling 
Interventions: Impact on Consumer and Restaurant Behavior,” Obesity, vol. 25, no. 12, pp. 
2018–2044, 2017. 
[23] 
T. M. Cantu-Jungles, L. A. McCormack, J. E. Slaven, M. Slebodnik, and H. A. Eicher-Miller, “A 
meta-analysis to determine the impact of restaurant menu labeling on calories and nutrients 
(Ordered or consumed) in U.S. adults,” Nutrients, vol. 9, no. 10, pp. 20–22, 2017. 
[24] 
J. W. Davis and K. Bauman, “School enrollment in the United States: 2011,” U.S. Census 
Bureau, no. September. pp. 20–571, 2013. 
[25] 
C. L. Ryan and K. Bauman, “Educational attainment in the United States: 2015,” U.S. Census 
Bureau. pp. 20–578, 2016. 
[26] 
M. Smith, “Italian cuisine is world’s most popular,” YouGov, 2019. [Online]. Available: 
https://yougov.co.uk/topics/food/articles-reports/2019/03/12/italian-cuisine-worlds-most-
popular. [Accessed: 09-Jun-2018]. 
[27] 
U.S. Department of Health and Human Services and U.S. Department of Agriculture, “2015–
2020 Dietary Guidelines for Americans. 8th Edition.” pp. 1–46, 2015. 
[28] 
U.S. Department of Health and Human Services - Food and Drug Administration, “A Labeling 
Guide for Restaurants and Retail Establishments Selling Away-From-Home Foods – Part II 
(Menu Labeling Requirements in Accordance with 21 CFR 101.11): Guidance for Industry.” pp. 
1–53, 2016. 
[29] 
N. E. Adler, E. Epel, G. Casterllazzo, and J. Ickovics, “Relationship of subjective and objective 
social status with psychological and physical health in healthy white women,” Heal. Psychol., 
vol. 19, no. 6, pp. 586–592, 2000. 
[30] 
A. Steptoe, T. M. Pollard, and J. Wardle, “Development of a Measure of the Motives 
Underlying the Selection of Food: the ‘Food Choice Questionnaire,’” Appetite, vol. 25, pp. 
267–284, 1995. 
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M. C. Onwezen, M. J. Reinders, M. C. D. Verain, and H. M. Snoek, “The development of a 
single-item Food Choice Questionnaire,” Food Qual. Prefer., vol. 71, no. August 2017, pp. 34–
45, 2019. 

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[32] 
I. Trizano-Hermosilla and J. M. Alvarado, “Best alternatives to Cronbach’s alpha reliability in 
realistic conditions: Congeneric and asymmetrical measurements,” Front. Psychol., vol. 7, no. 
MAY, pp. 1–8, 2016. 
[33] 
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of perceived weight status,” Obes. Sci. Pract., vol. 3, no. 1, pp. 36–43, 2016. 
[34] 
E. Robinson, P. Aveyard, and S. A. Jebb, “Is plate clearing a risk factor for obesity? A cross-
sectional study of self-reported data in US adults,” Obesity, vol. 23, no. 2, pp. 301–304, 2015. 
[35] 
United States Census Bureau, “Income and and Poverty Poverty the United States : 2017,” no. 
September 2018. pp. 60–263, 2018. 
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M. Laxy, C. Teuner, R. Holle, and C. Kurz, “The association between BMI and health-related 
quality of life in the US population: Sex, age and ethnicity matters,” Int. J. Obes., vol. 42, no. 
3, pp. 318–326, 2018. 
[37] 
A. Breck, J. Cantor, O. Martinez, and B. Elbel, “Who reports noticing and using calorie 
information posted on fast food restaurant menus?,” Appetite, vol. 81, pp. 30–36, 2014. 
[38] 
A. F. Hayes, “PROCESS: A Versatile Computational Tool for Observed Variable Mediation, 
Moderation, and Conditional Process Modeling,” White Paper, 2012. [Online]. Available: 
http://www.afhayes.com/ public/process2012.pdf. 
[39] 
R. Pechey et al., “Impact of increasing the proportion of healthier foods available on energy 
purchased in worksite cafeterias: A stepped wedge randomized controlled pilot trial,” 
Appetite, vol. 133, pp. 286–296, 2019. 
[40] 
E. Van Kleef, K. Otten, and H. C. M. Van Trijp, “Healthy snacks at the checkout counter: A lab 
and field study on the impact of shelf arrangement and assortment structure on consumer 
choices,” BMC Public Health, vol. 12, no. 1, pp. 1–10, 2012. 
[41] 
W. J. Browne, M. G. Lahi, and R. M. a Parker, “A Guide to Sample Size Calculations for 
Random Effect Models via Simulation and the MLPowSim Software Package School of Clinical 
Veterinary Sciences , University of Bristol * Tarbiat Modares University , Iran This draft – 
March 2009,” no. March. 2009. 
[42] 
R. Pechey, P. Monsivais, Y. L. Ng, and T. M. Marteau, “Why don’t poor men eat fruit? 
Socioeconomic differences in motivations for fruit consumption,” Appetite, vol. 84, pp. 271–
279, 2015. 
[43] 
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Psychol. Sci., vol. 18, no. 3, pp. 233–239, 2007. 
[44] 
B. Ellison, J. L. Lusk, and D. Davis, “Looking at the label and beyond: The effects of calorie 
labels, health consciousness, and demographics on caloric intake in restaurants,” Int. J. 
Behav. Nutr. Phys. Act., vol. 10, pp. 1–9, 2013. 
[45] 
B. Ellison, J. L. Lusk, and D. Davis, “The impact of restaurant calorie labels on food choice: 
Results from a field experiment,” Econ. Inq., vol. 52, no. 2, pp. 666–681, 2014. 
[46] 
E. M. VanEpps, J. S. Downs, and G. Loewenstein, “Calorie Label Formats: Using Numeric and 
Traffic Light Calorie Labels to Reduce Lunch Calories,” J. Public Policy Mark., vol. 35, no. 1, pp. 
26–36, 2016. 
 
 

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9. APPENDIX A: PROCESS OF ORDERING MAINS ITEMS ON THE MENUS 
For the all conditions, the lowest calorie and highest calorie item were identified. Meanwhile, the 
remaining eight items were categorised as either ‘higher’ or ‘lower’ calorie items, making sure that 
there were four items in each of these categories. Below is the example of this for the American 
C/CL condition.  
Classic Broccoli Blackened Shrimp 
Alfredo 
1360 kcal 
Highest  
Riblet Platter 
1290 kcal 
Higher  
Brunch Burger 
1220 kcal 
Higher  
Double Crunch Shrimp 
1170 kcal 
Higher  
Clubhouse Grillle 
1040 kcal 
Higher  
Grilled Chicken Caesar Salad 
970 kcal 
Lower  
Classic Bacon Cheeseburger 
870 kcal 
Lower  
Chicken Wonton Stir Fry 
790 kcal 
Lower  
Signature Bourbon Street Steak  
650 kcal 
Lower  
Cedar Salmon with Maple 
Mustard Glaze 
370 kcal 
Lowest  
 
It was agreed that it is important that the lowest and highest calorie option are featured in certain 
positions on the menu. For example, it is important that the highest calorie option is featured at the 
‘top’ of the menu as well as the ‘bottom’ and also being featured in the ‘middle’ of the menu. It is 
also important that the lowest calorie option is also featured on the menu in the same positions. 
Below is a table outlining what we mean by ‘top’ ‘middle’ and ‘bottom’ of the menu.  
 
Below are six menu scenarios where you can see how these categories have formed different menu 
listings. 
  
1 
2 
3 
4 
5 
6 
Top 
Highest 
Lower 
Lower 
Highest 
Lowest 
Higher 
Higher 
Lowest 
Lower 
Higher 
Higher 
Lower 
Position 1 
Top  
Position 2 
Top  
Position 3 
Middle  
Position 4 
Middle  
Position 5 
Middle  
Position 6 
Middle  
Position 7 
Middle  
Position 8 
Middle  
Position 9 
Bottom  
Position 10 
Bottom  

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Middle 
Higher 
Lower 
Higher 
Lowest 
Higher 
Lower 
Lower 
Higher 
Lower 
Higher 
Lower 
Higher 
Lower 
Higher 
Lower 
Highest 
Lower 
Higher 
Higher 
Lower 
Higher 
Lower 
Higher 
Lower 
Lower 
Higher 
Lowest 
Higher 
Lower 
Higher 
Higher 
Lower 
Highest 
Lower 
Higher 
Lower 
Bottom 
Higher 
Lower 
Lowest 
Higher 
Lower 
Higher 
Highest 
Lower 
Lower 
Highest 
Higher 
Lowest 
 
It was also agreed that when ‘highest’ or ‘lowest’ items were featured in either the ‘top’ or ‘bottom’ 
positions, they should be counterbalanced by the opposite pair. For example, when the ‘highest’ 
item is at the top, this should be matched with a ‘lower’ item also being featured in the top section. 
Similarly, if the ‘lowest’ item was at the top, this should be matched with a ‘higher’ item also at the 
top. 
In order to decide in what order the ‘lower’ and ‘higher’ options would feature in the menu, a 
random number generator was used. For example, using Excel the lower and higher items were 
assigned random values spanning from 1-10,000 and then coded from 1 to 8 in ascending order. 
Items with number 1 were listed first, either in the top segment (either higher or lower – explained 
above) or bottom segment. For the remaining ‘higher’ and ‘lower’ category items these were listed 
alternately according to their random number value, i.e. item number 2 was followed by 3 etc. 
 
 

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10. APPENDIX B: GLOBAL CUISINE SURVEY SUMMARY 
Cuisine 
I have never eaten this cuisine (%)* 
American 
8 
Mexican 
8 
Italian 
9 
Chinese 
13 
Spanish 
17 
Japanese 
22 
Greek 
24 
French 
25 
German 
27 
Thai 
29 
British 
31 
Indian 
31 
Caribbean 
35 
Korean 
38 
Vietnamese 
40 
Swedish 
42 
Brazilian 
47 
Filipino 
48 
Moroccan 
49 
Hong Kong 
49 
Danish 
50 
Taiwanese 
50 
Norwegian 
51 
Lebanese 
51 
Argentinian 
52 
Turkish 
53 
Indonesian 
53 
Australian 
53 
Peruvian 
53 
Finnish 
54 
Malaysian 
54 
Singaporean 
56 
Saudi Arabian 
59 
Emirati 
60 
*1,184 US respondents 
 
 

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11. APPENDIX C: AUDIENCE (PROLIFIC WEBSITE) 
 
1. Age 
o 18 years old or above 
 
2. Current country of residence 
o US 
 
3. Fluent language 
o English 
 
4. Diet restriction 
o None 
 
5. Gender 
50% of participants 
o Male 
50% of participants 
o Female 
 
6. Students 
92% of participants 
o No 
8% of participants 
o Yes 
 
7. Highest education level 
70% of participants 
o No formal qualifications 
o Secondary school / GCSE 
o College / A level 
30% of participants 
o Undergraduate degree (BA, BS, other) 
o Graduate degree (MA, MSc, MPhil, other) 
o Doctoral degree (PhD, MD, other) 
 
 

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12. APPENDIX D: RECRUITMENT TEXT 
“This is a study examining food choices at restaurants. You will choose between different foods in 
various restaurants, and fill some questionnaires in about yourself. Overall the study will take about 
15 minutes. 
If you would like to take part, please make sure that: 
- You have 15 minutes to complete this study, it must be taken in one sitting and you cannot exit and 
return to the study. 
- You read the instructions carefully and answer the questions as accurately as possible. 
Failure to comply with these instructions may result in your submission being rejected. Attention 
checks have been included, failing them will result in your submission being rejected.” 
 
 

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13. APPENDIX E: INFORMATION PAGE 
 
Fast Food Study 
 
You are being invited to participate in a research study. Before you decide 
whether to participate, it is important for you to understand why the research is 
being done and what it will involve. Please take time to read the following 
information carefully and feel free to ask us if you would like more information 
or if there is anything that you do not understand. We would like to stress that 
you should only agree to take part if you want to. 
 
What is the purpose of the study? 
The purpose of the study is to understand how different people make food choices 
at restaurants 
  
Why have I been chosen to take part? 
 
We are recruiting volunteers who fulfil the following criteria: 
1. Aged ≥ 25 years 
2. Fluent English speaker 
3. Reside in the US 
4. Do not have any dietary restriction 
 
Do I have to take part? 
No. Participation in this research is completely voluntary. You are free to withdraw 
at any time without explanation and without incurring a disadvantage. 
 
What will happen if I take part? 
You will provide some information about yourself (e.g., age, gender), before then 
completing a meal choice task based on different restaurants menus. So that your 
awareness of the study hypotheses does not affect your behaviour in the study we 
provide more detailed information about the study aims at the end of the study. If 
you feel uncomfortable about this then you are free not to participate in this 
study. Overall the study will take 15 minutes. 
 
How will my data be used? 
The University processes personal data as part of its research and teaching 
activities in accordance with the lawful basis of ‘public task’, and in accordance 
with the University’s purpose of advancing education, learning and research for 
the public benefit. University of Liverpool employee Victoria Heath 
(V.Heath@liverpool.ac.uk) acts as the Data Protection Officer for this study and 
any queries relating to the handling of your personal data can be sent to her or the 
principal investigator (see contact details below). Further information on how 
your data will be used can be found in the table below. 

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Are there any risks in taking part? 
There are no anticipated risks to you if you take part in the study. 
 
Are there any benefits in taking part? 
There are no direct benefits, other than the small monetary payment. 
 
What will happen to the results of the study? 
We intend to publish the results from this study in a scientific journal. However, 
as explained above any personal information you provide is deleted before this 
and you would therefore not be identifiable in report. If you are interested in the 
results of the study, please let us know and we will share the results of the study 
with you when we publish it. 
 
What will happen if I want to stop taking part? 
You are under no obligation to take part in this study; it is completely your 
choice. If you do decide to take part, you are free to withdraw at any time and 
without giving any reason or explanation. Data collected up until the period you 
How will my data be collected? 
Through an online questionnaire. 
How will my data be stored? 
On a password protected computer server. 
How long will my data be stored for? 
Your personal data will be stored for up to 28 
days and then deleted. All other information will 
be stored indefinitely. 
What measures are in place to protect the 
security and confidentiality of my data? 
We will store all data on password protected 
computer servers and we never share any of 
your personal data outside of the research team 
for this project.  
Will my data be anonymised? 
After the study your personal information will be 
stored separately from your other questionnaire 
responses to create an anonymised data set. 
After 28 days all personal information will be 
deleted, but up to this point you can contact us 
and ask to see your information or have it 
deleted. 
How will my data be used? 
Your anonymised data will be combined with 
other participants’ data in order to be analysed. 
Who will have access to my data? 
The research team for this project will have 
access to your data. 
Will my data be archived for use in other 
research projects in the future? 
After the research team have anonymised your 
data and completed this research project, they 
will place the anonymised data sets on an 
archive (e.g. Open Science Framework) in case 
any other researchers want to use it for future 
research purposes.  
How will my data be destroyed? 
Your 
personal 
data 
will 
be 
destroyed 
electronically (deleting the files and removing 
them from the computer server).  

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withdraw may be used, but only if you are happy for this to be done. Otherwise 
you may request that your data be destroyed and no further use is made of them. 
 
What if I am unhappy or if there is a problem? 
If you are unhappy, or if there is a problem, please feel free to let us know by 
contacting Dr Lucile Marty (contact details below) and we will try to help. If you 
remain unhappy or have a complaint which you feel you cannot come to us with 
then you should contact the Research Governance Officer on 0151 794 8290 
(ethics@liv.ac.uk). Please provide details of the name or description of the study 
(so that it can be identified), the researcher(s) involved, and the details of the 
complaint you wish to make. 
 
Who can I contact if I have further questions? 
Please contact the principle investigator:  
Dr Lucile Marty 
2.41b, Eleanor Rathbone Building 
Bedford Street South 
University of Liverpool, 
Liverpool,  
L69 7ZA, 
UK 
email: lucile.marty@liverpool.ac.uk 
 
or the data protection officer: 
Victoria Heath 
The Foundation Building, 
765 Brownlow Hill, 
University of Liverpool, 
Liverpool, 
L69 7ZX, 
UK, 
email: V.Heath@liverpool.ac.uk  
 
I confirm I have read the information sheet 
 
o Yes 
 
 

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14. APPENDIX F: CONSENT PAGE 
 
Fast Food Study 
 
I confirm that I have read and have understood the information sheet for the 
above study. I have had the opportunity to consider the information, ask questions 
and have had these answered satisfactorily. 
 
I understand that taking part in the study involves completing online tasks and 
questionnaires 
 
I understand that my participation is voluntary and that I am free to stop taking 
part and can withdraw from the study at any time without giving any reason and 
without my rights being affected. I also understand that I have the right to lodge a 
complaint. 
 
I understand that the information I provide is for research purposes and it will be 
held securely in line with data protection requirements at the University of 
Liverpool. In addition, I understand that personal information collected about me 
that can identify me will never be shared beyond the study team. 
 
I understand that shortly after completing the study, researchers will keep my 
personal data and store it separately from my other questionnaire responses for up 
to 28 days on a computer, so that my anonymised questionnaire responses can 
later be deposited in an online data archive for sharing and used by other 
authorised researchers to support other research in the future. 
 
I understand that I can ask for access to any of the information I provide and I can request the 
destruction or alteration of that information if I wish for up to 28 days after participating in 
the study. I understand that following this I will no longer be able to request access to or 
withdrawal of the information I provide because this information will have been deleted. 
 
I provide my consent as a legal basis for the processing of my data as detailed previously, 
including the purposes of data processing, recipients of data and the right to withdraw my 
data. 

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I agree and consent to take part in the above study 
 
o Yes 
 
 

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15. APPENDIX G: BASELINE QUESTIONNAIRE 
 
1. Gender 
o Male 
o Female 
o Other 
 
2. Age 
o _ _ (free text; range of 25-99) 
 
3. Ethnicity 
o White, non-Hispanic 
o Black 
o Asian 
o Hispanic 
o Other 
 
4. What is your current employment status? 
o Full or part-time 
What is the full title of your main job? 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ (free text) 
For business owners, your business is valued at:  
$_ _ _ _ _ _ _ _ _ (free text) 
o Student 
o Retired 
o Temporary or permanently sick or disabled 
o Looking after home/family 
o Other unemployed 
 
5. What is your highest educational qualification? If you are a student please select the 
diploma being studied for. 
o Less than high-school 
o High-school completion 
o Some college or associate degree 
o Bachelor’s degree 
o Master’s degree 
o Doctoral or professional degree 
 
6. After leaving middle school (i.e. after 8th grade), how many further years of higher 
education did you study for? 
Examples: 
If you left middle school and did not go on to high school, your answer would be 0. 
If you left middle school and then studied for two years in high school, your answer would be 2. 
If you completed high school over four years and then also went to college for two years, your answer 
would be 6. 
o _ _ (free text) 
 

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7. What is your annual household income (before tax), including all earners in your 
household, in dollars (to the nearest $1000)? 
$_ _ _ _ _ _ (free text; range 0-999,999) 
 
8. How many people live at your house, including you? 
_ _ adult(s) or child(ren) aged 14 and over (free text; range of 1-20) 
_ _ child(ren) aged under 14 (free text; range of 1-20) 
 
9. This is an attention check. How many times have you visited the planet Mars? 
o Several times 
o Just once 
o Never 
 
10. Think of a ladder (see image) as representing where people stand in society. At the top of 
the ladder are the people who are best off—those who have the most money, most 
education and the best jobs. At the bottom are the people who are worst off—who have 
the least money, least education and the worst jobs or no job. The higher up you are on 
this ladder, the closer you are to people at the very top and the lower you are, the closer 
you are to the bottom. Where would you place yourself on the ladder?  
 
Choose the number whose position best represents where you would be on this ladder: 
_ _ (free text: range 1-10) 
 
11. How often, on average over the past year, have you had diner at restaurants? 
o Not in the last year 
o Less than once per month 
o 1-3 times per month 

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o 1-2 times per week 
o 3 times per week or more 
 
12. Are you currently dieting? 
o Yes 
o No 
 
13. Weight 
_ _ . _ kg 
 
14. Height 
_ _ _ cm 
 
15. How hungry do you feel? 
__________________________________________________________________________________ 
0 
 
 
 
 
 
 
 
 
 
 
 
100 
Not at all hungry  
 
 
 
 
 
 
    As hungry as I've ever felt 
 
 
 

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16. APPENDIX H: MEAL CHOICE TASK INSTRUCTION 
Before the task begins: 
“For this task, we would like you to imagine that you are going to eat out with friends for 
dinner. You will be asked to choose your meal from the menus of six different restaurants.” 
For each dining out scenario: 
“We would like you to imagine that you are eating out with friends for dinner at a […] style 
restaurant. On the next page you will be at the door of the restaurant, then taken inside the 
restaurant. Then, you will be asked to choose your meal from the menu. When making your meal 
choice, try to imagine you actually are in the restaurant and choose food items that you would eat.” 
On top of mains menus: 
“Please choose you main meal” 
On top of sides menus: 
“Would you like to order any sides?” 
On top of desserts menus: 
“Would you like to order any desserts?” 
 
 

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17. APPENDIX I: SINGLE ITEM FOOD CHOICE QUESTIONNAIRE 
Instruction: “Several different factors influence our choice of food. Listed below are a series of factors 
that may be relevant to your choice of foods. Read each item carefully and decide how important the 
item is to you. There are no right or wrong answers – we are interested in what is important to you” 
It is important to me that the food I eat on a typical day… 
 
 
Not at all 
important 
1 
Not 
important 
2 
Not very 
important 
3 
Neutral 
 
4 
Slightly 
important 
5 
Important 
 
6 
Very 
important 
7 
1. 
is healthy  
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
2. 
is a way of monitoring 
my mood (e.g., a good 
feeling or coping with 
stress’) 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
3. 
is convenient (in buying 
and preparing) 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
4. 
provides me with 
pleasurable sensations 
(e.g., texture. 
appearance. smell and 
taste) 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
5. 
is natural 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
6. 
is affordable 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
7. 
This is an attention 
check. Please choose 
the answer 2 ‘Not 
important’ 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
8. 
is familiar 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
9. 
helps me control my 
weight 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
10. 
is environmentally 
friendly 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
11. 
is animal friendly 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
12. 
is fairly traded 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
 
 
 

05/08/2019, pre-registered 
30 
US Restaurants Study Protocol 
18. APPENDIX J: DEBRIEFING 
Aim guessing: 
What do you think we were expecting to find in this study? 
[Free text] 
Questionnaire: 
1. There was an acceptable number of food items on the menus. 
 
o  
o  
o  
o  
o  
o  
o  
Strongly 
disagree 
Disagree 
Slightly 
disagree 
Neither 
agree or 
disagree 
Slightly 
agree 
Agree 
Strongly 
agree 
 
2. The food choices I made for each dining out scenario were influenced by how many calories I 
thought were in the food options available. 
 
o  
o  
o  
o  
o  
o  
o  
Strongly 
disagree 
Disagree 
Slightly 
disagree 
Neither 
agree or 
disagree 
Slightly 
agree 
Agree 
Strongly 
agree 
 
3. The food items available in the menus are common in […] style restaurants. 
 
Strongly 
disagree 
Disagree 
Slightly 
disagree 
Neither 
agree or 
disagree 
Slightly 
agree 
Agree 
Strongly 
agree 
American 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Mexican 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Italian 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Lebanese 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Peruvian 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Moroccan 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
 
4. The food items I picked for my meal in the […] style restaurant would be something that I 
would normally order in the real world. 
 
Strongly 
disagree 
Disagree 
Slightly 
disagree 
Neither 
agree or 
disagree 
Slightly 
agree 
Agree 
Strongly 
agree 
American 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Mexican 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Italian 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Lebanese 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Peruvian 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
Moroccan 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
o 
 
 
5. Have you ever tried? 
 American cuisine 

05/08/2019, pre-registered 
31 
US Restaurants Study Protocol 
 Mexican cuisine 
 Italian cuisine 
 Lebanese cuisine 
 Peruvian cuisine 
 Moroccan cuisine 
For each cuisines, if ticked: 
How often, on average over the past year, have you ate food from […] style 
restaurant? 
o Not in the last year 
o Less than once per month 
o 1-3 times per month 
o 1-2 times per week 
o 3 times per week or more 
 
 
 

05/08/2019, pre-registered 
32 
US Restaurants Study Protocol 
19. APPENDIX K: DEBRIEFING TEXT 
“In this study we were interested in the effect of nutrition interventions on food choices at 
restaurants. 
All the participants saw the same six dining out scenario but in four different conditions. In the first 
condition, the menus reflected the food offer that can be found in restaurants in the US – for the six 
specific cuisines; in the second one energy labels for each food item were added on the menus; in the 
third one the proportion of healthy food items (low energy) was increased; in the fourth one energy 
labels were added and the proportion of healthy food items was increased. We will compare the total 
energy of the food items selected by the participants from the four conditions. The results will help to 
identify the most promising intervention to reduce the overall energy when dining out. You saw 
familiar and unfamiliar restaurants menus because we will test whether the effect of the 
interventions is influenced by how familiar the menu options are. 
You also answered questionnaire about your food choices motivations and nutrition knowledge. We 
will test if the ones who are the most motivated by health in their food choices and who have better 
nutrition knowledge were more likely to use energy information when making food choices. 
Thank you very much for your participation in our study!”