Impact of Repeated Sweet Breakfasts on Subsequent Sweet Food Preferences and Intakes
Phase: NA
Conditions: Repeated Sweet Food Consumption
Sponsor: Bournemouth University

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SWEET BREAKFASTS STUDY 
 
Clinical Trial Registration: clinicaltrials.gov ID: NCT03442829, 21st Feb, 2018. 
Date of document: 01.04.20 
 

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Protocol 
This is a randomised controlled parallel-groups trial, in which participants will be randomized to 
consume either a sweet breakfast or a non-sweet breakfast for 6 days and then a further 13 days. 
Ratings and intakes of other sweet and non-sweet foods will be assessed at breakfast and at lunch on 
day 0 (baseline), day 7, and day 21. 
 
The study will be run in the Eating Behaviours Laboratory at Bournemouth University, UK. Participants 
will come to the laboratory on six occasions: for breakfast and lunch on Day 0 (baseline), Day 7 and Day 
21. On each day, participants will be asked to arrive fasted, having consumed no alcohol or undertaken 
any heavy exercise the day before. On each occasion, participants will first undertake the taste test and 
second eat from an ad-libitum test meal. The same procedure will be followed at breakfast and lunch. 
Breakfast will be consumed between 8:00am and 9:30am on each day, and lunch will be consumed four 
hours later. Participants will be required to adhere to the same times for breakfast and lunch on each 
test day. At the end of the test day on Day 0 and Day 7, participants will also receive a designated box of 
cereal with or without sweetener identified by ID number. At the start of the test day on Day 7 and Day 
21, participants will be queried regarding compliance. Returned cereal boxes will also be checked for 
consumption. At the end of the test day on Day 21, participants will also be queried over the taste of the 
breakfasts they had consumed and debriefed.  
 
Taste tests will be used to assess our primary outcome of pleasantness for sweet tasting foods and 
drinks at breakfast. Ad-libitum test meals will be used to assess our primary outcome of sweet food 
intakes at breakfast. Assessments will be made at lunch as well as breakfast for further secondary 
outcomes.  
 

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Taste tests: Participants will be required to consume a pre-specified small sample of each of three sweet 
foods and three non-sweet foods. These foods will be chosen as foods that consistently differ in taste, 
are familiar to all participants, represent a variety of textures, and are also served in the ad-libitum test 
meal. Real foods as opposed to sugared water solutions or similar will be used to enhance the validity of 
the ratings. Participants will be asked to consume each food in full in a pre-specified order, focus purely 
on the taste of the food in their mouths and then rate it immediately after consumption. Participants 
will then be asked to rinse their mouths with water and move to the next pre-specified food. 
Participants will rate the samples using 100 mm visual analogue scales (VAS) of: Pleasantness: ‘How 
PLEASANT does this food taste to you right now?, anchors ‘not at all pleasant’, ‘extremely pleasant’; 
Desire to Eat: ‘Now, rate how strong your DESIRE TO EAT more of this food is right now?’, anchors ‘not at 
all strong’, ’extremely strong’, and Sweetness: ‘How SWEET does this food taste to you right now?’, 
anchors ‘not at all sweet’, ‘extremely sweet’. Data for each measure will be combined across all three 
sweet foods and all three non-sweet foods for analysis.  
 
Ad-libitum test meals: The meal will be composed of foods that represent a standard UK cold buffet 
meal that could be acceptable for breakfast or lunch, and where an acceptable meal that is entirely 
sweet, entirely non-sweet or a mixture of sweet and non-sweet foods could be composed. All foods will 
be familiar to participants and are commonly consumed in the UK. Participants will be free to consume 
as little or as much as they wish, and intake will be assessed by measuring weight consumed. Weight of 
food consumed will then be converted into energy consumed and sugars consumed using 
manufacturers’ information. Outcomes for the study include percent weight consumed from sweet 
foods, percent energy consumed from sweet foods, and percent energy consumed from sugars.  
 

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Outcomes will be assessed at breakfast and lunch, on days 0, 7 and 21. Taste tests will be consistently 
undertaken immediately in advance of the buffet meal, thus measures of pleasantness, desire to eat and 
sweetness will not be affected by measurements of intake, and because the taste tests involve 
consumption of regulated specific small amounts of foods, intake outcomes are unlikely to be affected 
by the rating measures.  
 
Additional measures: Gender, age and BMI will be recorded to allow description of the sample. Hunger, 
fullness and thirst will also be measured prior to each meal to ensure against confounding. These 
measures will be made using 100mm VAS of: Hunger: ‘How HUNGRY do you feel right now?’, anchors 
‘not at all hungry’, ‘extremely hungry’; Fullness: ‘How FULL does your stomach feel right now?, anchors 
‘not at all full’, ‘extremely hungry’; and Thirst: ‘How THIRSTY do you feel right now?’, anchors ‘not at all 
thirsty’, ‘extremely thirsty’.  
 
Analysis Plan 
Data will be compiled in Excel and analysed in IBM SPSS. All data will be analysed on an Intention-to-
Treat basis, with missing data completed using last observation carried forward. Modelling techniques 
will not be used to estimate missing data, due to the number of outcomes to be considered. Significance 
is set at p=0.05.  
 
In advance of our main analyses, data will be investigated for differences between groups in 
demographic and baseline measures. This will be undertaken to investigate whether analyses 
investigating differences between intervention and control groups should consider these variables as 
confounders. If differences between groups are found, the variables will be included in subsequent 
analyses. These analyses will be undertaken using independent t-tests. 

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To address our primary research questions, rating data will be analysed using 2x3x2 ANOVA for 
differences between exposure conditions (sweet vs non-sweet) over time (Day 0, 7, 21), for the sweet 
and the non-sweet foods ((sweet vs non-sweet). Intake data will be analysed using 2x2x3 ANOVA for 
differences between genders (male vs female) and exposure conditions (sweet vs non-sweet) over time 
(Day 0, 7, 21). Main effects of gender will demonstrate known effects in food intake measures adding 
confidence to other findings. If interactions are also observed, these analyses will remain. If no 
interactions with gender are found, intake data will be re-analysed using 2x3 ANOVA for differences 
between exposure conditions (sweet vs non-sweet) over time (Day 0, 7, 21). This will be allow greater 
power. To allow the separation of our primary and secondary outcomes, analyses will be undertaken 
first for measures taken at breakfast, and secondly for measures taken at lunch.  
 
Associations between rating and intake outcomes will also be investigated using correlations across the 
whole data set. For these correlations, all data will be treated equally, regardless of day and breakfast / 
lunch test context, resulting in the inclusion of as many data points as possible.