The Impact of Food Reformulation on Energy Intake
Phase: NA
Conditions: Diet, Healthy, Eating Behavior, Obesity
Sponsor: University of Liverpool

Title: The Impact of Food Reformulation on Energy Intake
Date: 21/2/2023

Description: A study examining the influence of altering energy density on acute consumption and
later compensation.
Contributors: Amy Finlay, Emma Boyland, Andrew Jones, Eve Bending, Manraj Malhi & Eric Robinson
Category: Project
Affiliated institutions: University of Liverpool
License: CC-By Attribution 4.0 International
Subjects: Psychology, Life Sciences, Health Psychology
Background:
Food prepared outside of the home tends to have a high energy content, and high levels of nutrients
of concern (sodium, fat, saturated fat and sugar)(1), especially when compared to home-cooked
food(2). Over time, food prepared outside of the home has become increasingly accessible and
convenient, particularly since the start of the coronavirus pandemic(3, 4) where the use of food
delivery services increased substantially. It is anticipated that a population-level approach would be
most beneficial to combat the impact of these changes on diet and health(5). This has prompted
policies enforcing reformulation, for example the soft-drinks industry levy (SDIL) and the salt
reduction programme have both seen success in the UK in reducing intake of sugar and salt in the
population, and perhaps more importantly, encouraging the food industry to provide healthier
alternatives(6, 7). More recently proposed in the UK is the calorie reduction programme which
challenges the food industry to achieve a 20% reduction in calories by 2024(5), with specific
recommendations for food categories, and the out-of-home sector. A key benefit of this programme
is that little burden is placed on the public to make healthy choices, as the foods consumed every
day will become healthier, with little need for individuals to review and sustain changes(5).
Energy density is defined as “the energy content per unit weight of food”(8) and is measured as
kilocalories per gram (kcal/g). Foods with a low energy density tend to have a high water content
(i.e. fruits and vegetables), and foods with high energy density are typically ultra-processed, with
higher fat, carbohydrate and sugar content(9). Together, the water and fat content of a food account
for 99% of the variance in energy density(9). A diet characterised as higher energy density is
associated with higher total energy intake(10, 11) and relationships have been identified in both
adults and children between higher dietary energy density and heavier body weight(12). Humans
evolved consuming low energy dense foods (<1.75kcal/g) so it is unclear whether we have adapted
to differentiate sufficiently, and therefore compensate for, the high energy density foods present in
the modern diet(13).
A number of studies suggest that when energy density of a food is manipulated it has a linear effect
on energy intake, because consumers tend to eat a constant weight of food(14). This evidence
comes from studies that have measured the impact of covert manipulations of energy density on
food intake. For example in the US, an older group of participants who relied on home delivered
meals were given regular (1.1kcal/g) or enhanced (2.2kcal/g) meals(15). When the enhanced meal
was provided, kcal intake at lunch increased by 86% and there was an average increase in 453kcals
over 24 hours. In another study, healthy males were given a lunch of noodle soup at one of five
different levels of energy density (ranging from 0.27kcal/g to 1.81 kcal/g)(16). Total daily energy
intake differed significantly between conditions, and this was directly associated with intake at lunch
time; there was no evidence of participants adjusting their lunch time energy intake based on the
energy density of the meal or compensating for increases in energy intake at subsequent meals.

A limitation of existing research is that it tended to examine the effects of manipulating energy
density for relatively low energy dense foods and foods are manipulated covertly during a single
session, so consumers are not able to learn about the energy content(14). For example, in the two
studies mentioned, the highest energy densities tested were 1.8kcal/g(16) and 2.2kcal/g(15)
respectively. However, consumers often are exposed to and consume foods of higher energy
density. In one UK fast food restaurant menu, main meal items ranged from 1.9kcal/g to 3.2
kcal/g(17). This may be an important consideration because recent observational research suggested
that up to approximately 1.5-2kcal/g, individuals are relatively insensitive to changes in energy
density, and there is no indication of compensation through altering meal size(18). However,
upwards of approximately 1.5-2kcal/g, the authors proposed that individuals compensate for
increases in energy density by selecting and consuming smaller meal sizes. The proposed
explanation for this is that individuals rely on the volume of food as the dominant signal with energy
dilute foods (i.e.<1.5) and rely on calorie content as the dominant signal for energy rich foods(18).
The volume signal is related to gastric distention and the calorie content signal is related to both
learned and unlearned effects. If correct, the proposed model has implications for food product
energy reformulation, as it suggests that reducing the energy density of more energy dense food
products (e.g. >2.5kcal/g to 2kcal/g) may not lead to reductions in energy intake because within this
range of energy densities consumers adjust meal size to compensate for changes in energy density.
However, there has been no formal testing of the proposed model using experimental approaches
and it is unclear how efficiently consumers learn about the density of energy dense foods and adjust
their meal size accordingly. In a previous study, we tested whether consumers adjust the meal size
when given foods varying in energy density. This previous study measured the meal size of three
desserts that were familiar to participants with the same basic ingredients (vanilla yoghurt, vanilla
ice cream, vanilla cheesecake) but varying in energy densities (1.2kcal/g, 1.9kcal/g, 3.5kcal/g), with
the aim of understanding the extent to which learned energy density would influence intake.
We aim to follow up on this previous study, by covertly manipulating the level of energy density of a
meal, using the same parameters as the prior study. In this previous study the foods provided were
noticeably different to participants, and so underlying preferences and differences in sensory and
nutritional aspects of the meals may have influenced the amount consumed. Equally, this study did
not measure whether later intake differed following consumption of desserts varying in energy
density. For the present study, the foods provided will be variations on the same meal (loaded fries),
so participant’s expectations of the meals should be comparable. This will help us to understand
whether reformulation to approximately 2kcal/g would lead to a reduction in energy intake, or if
further reduction, below 1.5kcal/g is required to influence immediate eating behaviour positively by
reducing energy intake. Additionally, if there are significant effects of energy density, it is vital to
determine whether these changes are compensated for by consumers later on in the day.
Primary objectives: To observe differences in consumption (g/kcal) when participants are given a
meal covertly manipulated to be low, medium or high in energy density.
Secondary objective: To measure later food intake, in order to observe any evidence of later
compensation in response to experimental condition.
To measure intake over the full day, in order to understand whether one manipulated meal impacts
daily energy intake.
Study Information

Hypotheses:
Based on Flynn et al(18), it is hypothesised that as the energy density of the lunch meal increases
from low ED to medium ED, the amount of the lunch consumed (g) will remain similar, but due to
the increased energy density, the calories consumed will increase.
As energy density of the lunch meal increases from medium ED to high ED, the amount of lunch
consumed (g) will decrease, due to people compensating for the increase in energy density (i.e.,
participants will attend to satiety signals and adjust meal size).
Design Plan
Study type: Experiment - A researcher randomly assigns treatments to study subjects, this includes
field or lab experiments. This is also known as an intervention experiment and includes randomized
controlled trials.
Blinding: For studies that involve human subjects, they will not know the treatment group to which
they have been assigned.
Is there any additional blinding in this study? To attempt to reduce the likelihood of aim guessing,
participants will be recruited to a study labelled as ‘a study of diet on cognitive function’.
Study design: An experimental, within-subjects design. Participants will be asked to visit the lab for
three consecutive weeks to complete some questionnaires and eat meals at lunch time and dinner
time. Participants will complete all three conditions – low energy density, medium energy density
and high energy density meals which will be eaten ad-libitum. Participants will be provided with a
box of snacks to eat throughout the day if they wish to, and will return to the lab for dinner, where
they will be served an ad-libitum meal and a dessert.
Randomization: Participants will complete all three conditions. The order the conditions are
presented to participants will be randomised prior to arrival.
Sampling Plan
Existing Data: Registration prior to creation of data
Explanation of existing data: N/A
Data collection procedures: Participant database. If required, participants will also be recruited from
the local community (e.g. adverts on social media/posters in the university)
Inclusion criteria:
·
Currently reside in the UK
·
Over the age of 18 years
·
Fluent English speaker
·
Like the test foods
·
Have a BMI between the ranges of 18.5 and 35.
Exclusion criteria:
·
Pregnant/breastfeeding
·
Partaking in a fast or other restrictive eating for religious reasons at time of participation

·
Currently following a diet
·
On medication that affects appetite
·
Being a smoker
·
Current or historic eating disorder
·
Dietary restrictions/intolerances including:
o Any allergies
o Vegan/vegetarian
o Gluten-free
o Dairy-free
o Sugar-free
Procedure:
Once signed up, participants will attend a short screening session, where they will be asked to
complete a medical history questionnaire, a baseline demographic questionnaire, have their height
and weight measured, and check they like the test foods on offer.
Participants will be told upon registration that they should have the same breakfast the morning of
each session. Arrangements will be made for the participants to arrive at the lab around the time
they would usually eat their lunch (11.30-2.30) and be allocated to one of the following groups for
each session (order randomised):
·
Low energy density lunch
·
Medium energy density lunch
·
High energy density lunch
Upon arrival, participants will be asked to complete some questionnaires whilst their meal is being
prepared. Questionnaires include:
-
All three visits
o Level of hunger/fullness
o Cognitive task
-
Final visit
o Follow-up questionnaire (Satiety responsiveness questionnaire, compensatory
health beliefs)
o Aim guessing/ranking meals
Participants will be provided with their lunch (loaded fries). There will be a large bowl of chips (low
ED; 1.17kcal/g; medium ED; 1.74kcal/g; high ED; 3.00kcal/g), and a separate large bowl of chilli at
low (1.1kcal/g), medium (1.6kcal/g) or high (3.2kcal/g) ED. Participants will serve themselves from
the provided bowls. The three different chilli recipes will be made in the lab using a standardised
procedure. ED will be varied by altering the ingredients used, and proportions of ingredients. A
review of existing energy density manipulation studies(14) found that very similar effects were
identified in studies whether the nutritional composition was altered or not, so it was deemed
appropriate to alter the nutritional content of the meal. Details of all food served are shown in Table
1. These recipes will be made in bulk, frozen and labelled clearly so each portion can be defrosted
and prepared for each participant on the day of consumption.
Loaded fries were chosen as the test meal, as it is a food frequently served in the out-of-home food
sector, and a meal which is relatively simple to manipulate in terms of energy density. The recipes

were tested several times to ensure they were equally appetising, and sent to the SGS Cambridge
Analysis Lab to ensure they contained the expected energy densities.
Throughout the study, random samples of each chilli will be sent off to the SGS Cambridge Analysis
Lab to test for nutritional content of each of the products. This will ensure that nutritional
components remain consistent over the course of the study. We plan to do this twice over the
course of data collection.
The amount of food served will fill a large serving bowl (750g of each chilli, with 500g of chips).
Participants will be left alone and asked to eat as much or as little of their meal as they would like.
When they have finished their meal, participants will be told to call the researcher back in to
continue the study. The plate will be taken from participants and any remaining food weighed in
order to calculate total grams and energy consumed. Participants will be asked to rate sensory
aspects of the meal.
After each lunch session, participants will be provided with a snack box, and told they can eat as
much or as little of what is provided as they wish.
Participants will return for an evening session to eat their dinner (4.30-6.30). They will be required to
bring the snack box, and any remaining snacks with them. Here, participants will once again be asked
to complete hunger and fullness scales, and a cognitive task. Following this, a 3-cheese pasta ready
meal (800g) with a side of mixed vegetables (225g) will be provided for participants to serve
themselves. Once participants have eaten all they wish to of the pasta meal, dessert will be provided
(brownie bites and flapjack bites) which once again, they can help themselves to as much or as little
as they would like.
After their final study dinner, participants will be given a follow-up questionnaire to assess
compensatory health beliefs and satiety responsiveness. They will also be asked to guess the aim of
the study and rank the foods they have eaten for each lunch session in terms of healthiness.
Following this they will be fully debriefed.
Table 1: All test foods
Low ED
Medium ED
High ED
g
LUNCH
Potatoes         500
Chilli         750
Water         500
DINNER
Ready meal         800
Mixed vegetables         225
Water         500
DESSERT
Brownie bites         220
Flapjack bites         280
Water         500
SNACKBOX
Apple
268
Cereal bar          60
Crisps
50
Carrot batons         100
kcal
£
585           £1.27
885           £3.17
0             £0.00
1164          £3.50
84            £1.50
0             £0.00
860           £2.25
1260          £2.25
0             £0.00
142.04        £0.80
232.8         £0.67
270           £0.18
43            £0.58
g
kcal
£
500
870
£0.97
750            1275
£3.14
500               0
£0.00
800
1164
£3.50
225              84
£1.50
500               0
£0.00
220
860
£2.25
280            1260
£2.25
500               0
£0.00
268          142.04        £0.80
60            232.8         £0.67
50              270           £0.18
100              43            £0.58
g
kcal
£
500
1500
£2.16
750
2430
£3.92
500               0
£0.00
800
1164
£3.50
225              84
£1.50
500               0
£0.00
220
860
£2.25
280            1260
£2.25
500               0
£0.00
268          142.04       £0.80
60            232.8        £0.67
50              270         £0.18
100              43          £0.58

Biscuits
22
Dried fruit and
nut mix
25
Chilli
Mince
250
(5%/15%/20%)
Onion
75
Carrot                              100
Mushroom                      100
Tomato                            100
Tinned tomatoes           300
Cumin                                 2
Worcester sauce              2
Garlic
10
Beef stock                       150
Kidney beans                  100
Oregano                            1
Cream
50
Salt                                     1
Pepper                               1
Full portion when          750
prepared
KJ/100g
Kcals/100g
Fat/100g
Carbs/100g
Protein/100g
Moisture/100g
104.72
£0.17
22
133
£0.55
25
£1.43
313
£0.04
68
£0.05
52
£0.30
52
£0.27
52
£0.34
209
£0.04
2
£0.01
2
£0.16
10
£0.10
104
£0.21
78
£0.06
1
£0.16
52
£0.02
1
£0.02
1
885
£3.17
750
480
114
4.8
10.7
7.2
76.1
104.72
£0.17
133
£0.55
£1.82
£0.03
£0.03
£0.16
£0.14
£0.23
£0.04
£0.01
£0.16
£0.07
£0.16
£0.06
£0.23
£0.02
£0.02
1170
£3.14
540
156
8.7
7.2
12.1
70.2
22
104.72
£0.17
25
133
£0.55
769
£2.75
12                             £0.01
6                              £0.01
6                              £0.02
6                              £0.02
123                            £0.14
2                              £0.05
2                              £0.02
12                             £0.19
62                             £0.04
68                             £0.14
1                              £0.07
123                            £0.46
1                              £0.02
1                              £0.02
750         2430          £3.92
1348
324
24.5
7.3
18.7
47.2
Variables
Manipulated variables: Whether participants are provided with a low, medium or high energy dense
lunch.
Test meals: The ingredients to make all meals will be purchased from the supermarket Tesco, and
prior to and during data collection samples will be sent off to the SGS Cambridge Analysis Lab to test
for consistency in nutritional content within each of the products.
Measured variables:
-
Grams consumed
o Meal components will be weighed in their serving bowls before and after lunch and
dinner to determine how much has been consumed by each participant.
-
Energy consumed
o To calculate energy consumed at lunch and dinner the total grams consumed will be
multiplied by the energy density of the product (kcal/g, as obtained from the lab or
food packaging of ready-made products). Energy for each snack provided will be
calculated prior to giving participants snack boxes.
Participant characteristics
In order to characterise the sample and present outcomes by individual participant variables,
participants will be asked to report their gender, age and ethnicity. Height and weight data will also

be collected to calculate body mass index (BMI), so participants can be classed as having
underweight, healthy weight, overweight or obesity.
Measures of socioeconomic position (SEP)
Three measures of SEP will be taken:
Participants will be asked to report their highest educational qualification. If they are still studying,
they should report the diploma they are currently studying for. The categories provided will be:
-
Less than high school
-
High school completion
-
College or foundation degree
-
Bachelor’s degree
-
Master’s degree
-
Doctoral or professional degree
A subjective measure of their socioeconomic position using the MacArthur Scale of Subjective Social
Status (SSS) (19). SSS will be recorded as this measure has been found to have strong associations
with overweight and obesity(20).
Childhood SES(21): for this measure, participants will be asked to provide the educational
attainment and occupation of each primary caregiver at the time the individual was 8-10 years old.
Parental educational attainment will be reported in 6 categories, if there are two caregivers, the
average will be calculated.
1 = less than high school
2 = high school
3 = 2-year degree
4 = 4-year degree
5 = master’s degree
6 = doctorate/professional degree
Parental occupation will be coded independently by two researchers using Hollingshead’s 9-point
scale(22), and inter-rater reliability assessed.
Sensory ratings (Appendix E)
Participants will be asked to complete sensory ratings once they have finished their meal for:
-
Pleasant
-
Sweet
-
Savoury
-
Salty
-
Familiar
-
Filling
-
Soft
-
Appetising (visually)
All will be presented on visual analogue scales ranging from 1-100 anchored by “not at all” and
“extremely” respectively.
Measure of hunger/fullness

Situational levels of hunger and fullness will be obtained before and after lunch and dinner by using
visual analogue scales ranging from 1-100 anchored by “not at all” and “extremely” respectively.
Satiety responsiveness (Appendix F)
Participants will complete a satiety responsiveness subscale of the Adult Eating Behaviour
Questionnaire (AEBQ)(23)
Compensatory health beliefs (Appendix G)
Participants will complete a compensatory health beliefs questionnaire. This will be made up of 8
items, from the exercise and portion size subscales from the diet-related Compensatory Health
Beliefs Scale (Diet-CHBS)(24). Participants are required to rate all items from 1 (not at all) to 5 (very
much) for how much the compensatory health belief matches their own beliefs e.g. “To maintain
your weight, it is fine to eat a high caloric snack in between meals, if you compensate for this by
eating a smaller portion later in the day”.
Food diary
At each lunch session, participants will be asked to report any foods or beverages (excluding water)
consumed the morning of the study, to ensure nothing was consumed in the two hours prior to the
study, and to ensure breakfast is similar across the three sessions. At each dinner session,
participants will be asked to report any foods or beverages (excluding water) consumed that were
not provided by the researchers.
Aim guessing (Appendix H)
At the end of their final visit, participants will be asked what they believe the aims of the study to be.
Anyone that guesses the study aims to be investigating the influence of energy density on intake
(e.g. the healthiness/energy content of meal on how much was consumed at lunch time or at dinner
time) will be coded as being aware of study aims. One researcher will code awareness of aims and a
second researcher will independently verify.
Participants will then be asked to rank the three lunch time meals in terms of level of energy density.
Additional tasks
Additional tasks will be completed to account for the study description of ‘A study of diet on
cognitive function’. Before and after each lunch and dinner meal, participants will complete a Stroop
task.
Study flow
Visit 1
Visit 2
Visit 3
Participants who could not take part in the previous mood, diet and
RECRUITMENT
sleep study will be contacted to take part in this study (Appendix A)

SCREENING
INFORMED
CONSENT
RANDOMISATION
BASELINE
ASSESSMENTS
(Inquisit)
LUNCH
Participants will come
into the lab to be
screened. This will
involve:
Medical history
questionnaire
Baseline demographic
questionnaire (Appendix
B)
Height and weight
measurement
Ensuring they like all test
foods.
Participants will be
asked to read the
information sheet
(Appendix C).
Participants who want
to proceed will read the
consent form and tick a
box providing their
consent (Appendix D).
Before their first
session, the order that
meals are presented to
participants will be
randomized.
Participants will
complete a baseline
demographic
questionnaire, measures
of hunger and fullness,
and a cognitive task
Participants will be
provided with a glass of
water and their lunch
(low ED, medium ED and
high ED) to serve
themselves.
After eating the meal,
participants will be
asked to provide sensory
ratings (Appendix E).
Participants will
complete measures
of hunger and
fullness and a
cognitive task
Participants will be
provided with a
glass of water and
their lunch
(low/medium/high
ED) to serve
themselves.
After eating the
meal, participants
will be asked to
provide sensory
ratings.
Participants will complete
measures of hunger and
fullness and a cognitive
task
Participants will be
provided with a glass of
water and their lunch
(low/medium/high ED) to
serve themselves.
After eating the meal,
participants will be asked
to provide sensory ratings.

POST MEAL
POST-SESSION
DINNER
Participants will
complete the cognitive
task.
Measures of hunger and
fullness will be taken
again.
Participants will be
asked to report any
foods or beverages that
had been consumed
prior to arriving at the
lab.
Participants will take
home a snack box. They
will be told they can eat
as many or as few of the
snack items as they
wish.
After completing hunger
and fullness ratings and
a cognitive task again,
participants will be
provided with a glass of
water and a ready-meal
for dinner, which they
can serve themselves.
After dinner,
participants will be
provided with a dessert
to have as much or as
little of as they like.
Participants will
complete the
cognitive task.
Measures of
hunger and fullness
will be taken again.
Participants will be
asked to report any
foods or beverages
that had been
consumed prior to
arriving at the lab.
Participants will
take home a snack
box. They will be
told they can eat as
many or as few of
the snack items as
they wish.
After completing
hunger and fullness
ratings and a
cognitive task
again, participants
will be provided
with a glass of
water and a ready-
meal for dinner,
which they can
serve themselves.
After dinner,
participants will be
provided with a
dessert to have as
much or as little of
as they like.
Participants will complete
the cognitive task.
Measures of hunger and
fullness will be taken
again.
Participants will be asked
to report any foods or
beverages that had been
consumed prior to arriving
at the lab.
Participants will take home
a snack box. They will be
told they can eat as many
or as few of the snack
items as they wish.
After completing hunger
and fullness ratings and a
cognitive task again,
participants will be
provided with a glass of
water and a ready-meal
for dinner, which they can
serve themselves.
After dinner, participants
will be provided with a
dessert to have as much or
as little of as they like.

Participants will
complete hunger and
fullness ratings and a
cognitive task again.
POST-MEAL
Participants will
complete hunger
and fullness ratings
and a cognitive task
again.
Participants will complete
hunger and fullness ratings
and a cognitive task again.
Participants will complete
measures of satiety
responsiveness (Appendix
F) and compensatory
health beliefs (Appendix
G).
Aim guessing in an open-
ended response format
will be provided to
participants (Appendix H).
DEBRIEFING
DATA
MANAGEMENT
Following this, participants
will be asked to rank the
meals from the three
weeks in order of energy
density.
Participants will be
debriefed on study aims
(Appendix H).
The result files will contain:
o Participant unique ID (randomly generated)
o Demographic and questionnaire data
o Amount of each lunch meal consumed (g)
o Energy consumed for each lunch (kcal)
o Snacks consumed
o Amount of dinner and dessert consumed (g)
o Energy consumed for dinner and dessert (kcal)
Analysis Plan
Participant characteristics:
Only participants who have completed the entire study (all three visits) will be included in analysis.
We will report analyses with any participants who guess the aims of the study included and
excluded.
If any participants do not follow study instructions (e.g. do not consumer any or only a very small
amount of any of the food (<50kcal) then they will be removed from primary analyses.
Participant characteristics will be presented in a table. Data will include age, gender, ethnicity, BMI,
highest education level, perceived social status, childhood SEP, compensatory health beliefs and
satiety awareness. Continuous variables will be summarised by means and standard deviations,
categorical variables will be summarised by counts and percentages.
Primary analyses:

Two repeated-measures, within-subjects ANOVAs will assess lunchtime (manipulated meal) kcal and
gram intake across the three conditions. Where significant main effects are identified, post-hoc
pairwise comparisons will be performed to identify where these differences exist. Sensory ratings of
the three meals will be compared using repeated-measures, within-subjects ANOVAs to assess
whether all meals were rated equally. Results will be considered statistically significant at p<0.05.
Secondary analyses:
Two repeated-measures, within-subjects ANOVAs will assess later kcal and gram intake (dinner,
dessert and snacks) across the three conditions (low ED, medium ED and high ED). Where significant
main effects are identified, post-hoc analyses will be performed to identify where these differences
exist.
A repeated-measures, within-subjects ANOVA will assess daily energy intake (sum of lunch, dinner,
dessert, snacks and additional food) across the three conditions. Where significant main effects are
identified, post-hoc analyses will be performed to identify where these differences exist.
To account for multiple comparisons, results for secondary analyses will be considered significant at
p<.01.
Sensitivity analyses:
We will examine evidence of extreme outliers (+3 standard deviations from the session mean) in
grams consumed for each test food, and for any outcomes identified as outliers we will examine the
effect of winsorizing the outlier.
If we find evidence that meals differ in sensory ratings then we will also examine if results remain
the same when sensory ratings are controlled for in analyses as a covariate.
We will also examine if results remain the same among participants who accurately identify the
differences in energy density between foods vs. participants who do not. Alternatively, if only a small
number of participants are unable to identify the correct order of energy density then we will
examine if results remain the same when excluded.
We will report whether sensitivity analyses deviate from primary analyses (e.g. if significant findings
become non-significant and vice versa).
Transformations: N/A
Inference criteria: Results for primary analyses will be considered significant at p<0.05, and to
account for multiple comparisons, secondary analyses will be considered significant at p<0.01.
Data exclusion: If participants drop out of the study, any data will be excluded from analyses.
Missing data: For participants who complete all three study sessions, it is not anticipated that
missing data will be a problem. If there is missing data, participants will be excluded from analyses.
Exploratory analysis:
Other:
Sample size:
A previous study provided three desserts differing in energy density to participants over three
consecutive weeks. Grams consumed and kcals consumed for each dessert were recorded. The

influence of energy density on intake (g) was significant (p<.001), with a partial eta squared of 0.4
(large effect). The influence of energy density on kcals eaten was also significant (p <.001) with a
partial eta squared of 0.7 (large effect). As the relative energy density of the meals will be unknown
to participants (desserts were familiar in the previous study), it is anticipated that effect sizes will be
smaller than observed in the previous study. We will power the present study to be able to detect a
medium effect size of f=0.25 through a repeated-measures, within factors ANOVA consisting of three
measures at 0.95% power. This will require a minimum sample of 28 participants.
If the findings of the ANOVA show significant differences between the three conditions, post-hoc
analyses will be conducted. In the previous study, the smallest effect observed had a Cohens D of
0.52. We will power the present study to be able to detect effects of this size at 0.8% power in post-
hoc t-tests, which will require a minimum sample of 32 participants.
Therefore, we will aim to recruit a minimum of 32 participants for this study.

Appendix A: Recruitment text
This is a study exploring the interaction between diet and cognitive function. If you wish to take part,
you will attend a screening session at the university of Liverpool (Eleanor Rathbone building) where
you will complete a medical history questionnaire and have your height and weight measured.
If you are eligible, you will be asked to come into the lab (Eleanor Rathbone building, University of
Liverpool) for three consecutive weeks for lunch and dinner. Before and after each meal you will be
asked to complete a cognitive task.
The lunch provided will be three variations of loaded fries (with beef chilli). You will be asked to
serve yourself the amount you would like to eat.
After lunch, you will be given a snack box to eat throughout the day if you wish, and when you
return in the evening, you will be given a three-cheese pasta for dinner, followed by a dessert of
chocolate brownies.
Following three days of testing you will complete a number of questionnaires.
If you would like to take part, please make sure:
·
You currently reside in or around Liverpool and are able to travel to the university for a
screening session and lunch and evening meals one day a week for three consecutive weeks.
·
You like the foods on offer for lunch and dinner.
·
You are 18 years or older
·
You are not taking any medication that affects your appetite
·
You are a fluent English speaker
·
You are not pregnant or breastfeeding
·
You are a non-smoker
·
You are not partaking in a fast or other restrictive eating for religious reasons at the time of
participation
·
You have none of the following dietary restrictions:
o Vegetarian/vegan
o Gluten-free
o Dairy-free
o Sugar-free
o Any food allergies

Appendix B: Baseline questionnaire
1.Gender

Male

Female

Other
2. Age:
3. Ethnicity:

White English/Welsh/Scottish/Northern Irish/British

White Irish

Any other White background

White and Black Caribbean

White and Black African

Any other mixed/multiple ethnic background please describe

Indian

Pakistani

Bangladeshi

Chinese

Other Asian

African

Caribbean

Arab

Any other ethnic group
4. What is your highest educational qualification?

Less than high school

High school completion

College or foundation degree

Bachelor’s degree

Master’s degree

Doctoral or professional degree
5. This is an attention check. How many times have you visited the planet Mars?

Several times

Just once

Never

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?
6. Choose the number whose position best represents where you would be on this ladder:
______
7: Please state the highest educational attainment of your primary caregiver(s) when you were
aged 8-10.
1 = less than high school
2 = high school
3 = 2-year degree
4 = 3/4-year degree
5 = master’s degree
6 = doctorate/professional degree
Primary caregiver 1 _____
Primary caregiver 2 _____

8: Please state the occupation of your primary caregiver(s) when you were aged 8-10.
Primary caregiver 1 ____
Primary caregiver 2 ____

Appendix C: Participant information sheet
A study of diet and cognitive function
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 the impact of diet on cognitive function.
Why have I been chosen to take part?
We are recruiting volunteers who fulfil the following criteria:
 You currently reside in or around Liverpool and are able to travel to the
university for lunch one day a week for three consecutive weeks.
 You like all of the foods on offer(chips, chilli, three-cheese pasta, chocolate
brownie, flapjack)
 You are 18 years or older
 You are a fluent English speaker
 You are not pregnant or breastfeeding
 You are not a smoker
 You are not currently on any medication that affects your appetite
 You are not partaking in a fast or other restrictive eating for religious reasons at
the time of participation
 You have none of the following dietary restrictions:
o Vegan
o Vegetarian
o Gluten-free
o Dairy-free
o Sugar-free
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?

Following a screening session where you will complete some questionnaires, a
medical history and have your height and weight measured, you will be required
to come to the lab (Eleanor Rathbone Building, University of Liverpool) for your
lunch and dinner one day a week for three consecutive weeks. You will be asked
to provide some information about yourself (e.g., age, gender), before
completing a cognitive task. You will then be provided with lunch and asked to
complete the cognitive task again. You will return later in the day for an evening
meal, where the same cognitive task will be completed before and after you eat
the meal. 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. The study should take approximately 180
minutes total (30 minutes per visit). You will be reimbursed £60 for your time,
plus travel expenses.
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 Amy Finlay
(a.finlay@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.
Further information on how your data will be used can be found in the table
below.
How will my data be collected?
Through measurement of in-person tasks,
questionnaires and food consumed.
How will my data be stored?
How long will my data be stored for?
What measures are in place to protect the
security and confidentiality of my data?
Will my data be anonymised?
How will my data be used?
Who will have access to my data?
On a password protected computer server.
Your personal data will be stored for up to 28
days and then deleted. All other information will
be stored indefinitely.
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.
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.
Your anonymised data will be combined with
other participants’ data in order to be analysed.
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?
How will my data be destroyed?
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.
Your
personal
data
will
be
destroyed
electronically (deleting the files and removing
them from the computer server).
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 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
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. We cannot guarantee payment if you do not complete all three visits.
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 Amy Finlay or Eric Robinson (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: Amy Finlay
2.19, Eleanor Rathbone Building
University of Liverpool,
Liverpool,
L69 7ZA,
email: a.finlay@liverpool.ac.uk

or the senior researcher: Prof. Eric Robinson
email: robinsoe@liverpool.ac.uk
I confirm I have read the information sheet
o Yes

Appendix D: Consent page
A study of diet and cognitive function
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 tasks,
questionnaires, and eating the lunch and dinner provided.
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.
I agree and consent to take part in the above study
o Yes

Appendix E: Sensory ratings:
Please rate the meal you just had on the following scales:
Pleasant
Not at all
1
Sweet
Not at all
1
Salty
Not at all
1
Savoury
Not at all
1
Extremely
100
Extremely
100
Extremely
100
Extremely
100
Appetising (visually)
Not at all
1
Familiar
Not at all
1
Filling
Not at all
1
Soft
Not at all
1
Extremely
100
Extremely
100
Extremely
100
Extremely
100

Appendix F: Satiety responsiveness
1.
I often leave food on my plate at the
end of a meal.
2.
I often get full before my meal is
finished.
3.
I get full up easily.
4.
I cannot eat a meal if I have had a
snack just before.
Strongly
disagree
1
o
o
o
o
Disagree
2
o
o
o
o
Neither agree
Agree
nor disagree
3
4
o
o
o
o
o           o
o           o
Strongly
agree
5
o
o
o
o

Appendix G: Compensatory Health Beliefs
Strongly
disagree
1
Disagree
2
Neither agree
Agree
nor disagree
3
4
Strongly
agree
5
1.
To maintain your weight, it is fine to
o
o
o
o
o
do less exercise if you eat small
portions
2.
To maintain your weight, it is fine to
o
o
o
o
o
have less exercise if you eat products
with a front-of-package logo
3.
When I eat less, it’s not necessary to
o
o
o
o
o
have a lot of exercise
4.
When I mainly eat products with a
o
o
o
o
o
front-of-package logo, it is not
necessary to have a lot of exercise
5.
If I eat a small meal, it’s fine to have
o
o
o
o
o
a larger portion during the next meal
6.
To maintain your weight, it is fine to
o
o
o
o
o
eat a large meal, if you eat a small
portion during the next meal
7.
To maintain your weight, it is fine to
o
o
o
o
o
eat a high caloric snack in between
meals, if you compensate for this by
eating a smaller portion later in the
day
8.
If I eat a small meal, there is no
o
o
o
o
o
harm in eating more cookies and
candies

Appendix H: Follow up questions
1. What do you think the aim of this study was?
2. Can you please rate the lunches you have been given in order of healthiness: i.e. write week 1,
week 2, week 3 in the spaces below.
a. ______________________ (healthiest)
b. ______________________
c.
______________________ (least healthy)

Appendix I: Debriefing text
In this study we were interested in the effect of energy density (measured by calories per gram of
food) on consumption – where the energy density of the loaded fries was different each week.
Energy density was altered by changing the ingredients (i.e. 20% fat beef mince/15% fat beef
mince/5% fat beef mince) or the proportions of ingredients (i.e. a greater proportion of vegetables).
All participants were presented with the same three meals, each in a random order.
We wanted to investigate whether people compensate when given a less healthy food option by
eating a smaller amount compared to when they are given less unhealthy options. Additionally, we
wanted to see if people compensate later in the day, by eating a smaller portion for dinner when
they had a less healthy meal at lunch.
We hypothesised that individuals would compensate more for the least healthy option by eating less
(whether at lunch time or dinner time).
The questionnaire about satiety responsiveness and compensatory health beliefs will be used to test
any characteristics and motivations that may impact the amount of food eaten.
If this study has raised any issues regarding your weight or eating behaviours, we recommend
contacting your doctor.
The following NHS page provides information and guidance on eating a healthy, balanced diet:
https://www.nhs.uk/live-well/eat-well/
Thank you very much for your participation in our study.
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