Food Preference Following Bariatric Surgery
Conditions: Obesity
Sponsor: Imperial College London

Food preference following bariatric surgery 
 
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Study Title: Food preference following bariatric surgery 
 
 
Principle Investigator: 
Prof Carel le Roux 
Metabolic Medicine Research Group 
Conway Institute of Biomolecular and Biomedical Research 
University College Dublin 
Belfield 
Dublin 4 
carel.leroux@ucd.ie 
 
Co-Investigators 
Dr Alan Spector 
1107 W. Call St. 
Florida State University  
Tallahassee 
FL 320306-4301 
USA 
spector@psy.fsu.edu 
 
 
Mr Justin Geoghegan 
Department of Surgery 
St Vincent’s University Hospital 
Elm Park 
Dublin 4 
 
 
Prof Donal O’Shea 
Department of Endocrinology 
St Vincent’s University Hospital  
Elm Park 
Dublin 4 
 
 

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Research Investigator 
Dr Loai Shakerdi 
Clinical Trial Co-ordinator 
Metabolic Medicine Research Group 
Conway Institiute of Biomolecular and Biomedical Research 
University College Dublin 
Belfield 
Dublin 4 
loai.shakerdi@ucd.ie 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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1 Overview............................................................................................................................ 4 
1.1 
Relevance ................................................................................................................................ 4 
2 Study Objectives and Design ......................................................................................... 4 
2.1 
Objectives ................................................................................................................................ 4 
2.2 
Design ....................................................................................................................................... 4 
3 Methodology ..................................................................................................................... 5 
3.1 
Recruitment ............................................................................................................................ 5 
3.1.1 
Participants................................................................................................................................... 5 
3.1.2 
Inclusion/Exclusion Criteria ................................................................................................... 5 
3.1.3 
Recruitment procedure.............................................................................................................. 6 
3.2 
Study Procedures .................................................................................................................. 8 
3.2.1 
Food Preference Questionnaire............................................................................................. 8 
3.2.2 
Participant Information and Consent .................................................................................. 8 
3.2.3 
Study Screening Questionnaire .............................................................................................. 8 
3.2.4 
Anthropometric measures ........................................................................................................ 8 
3.2.5 
Visual Analog Scale ................................................................................................................... 9 
3.2.6 
Venepuncture ................................................................................................................................ 9 
3.2.7 
Urinary pregnancy test .......................................................................................................... 10 
3.3 
Randomisation .................................................................................................................... 10 
3.4 
Study Drug preparation and administration .............................................................. 10 
3.5 
Buffet Meal .......................................................................................................................... 11 
3.6 
Clinical Nutritional Assessment ..................................................................................... 13 
4 Protocol Overview/Study visit and Event Schedule ................................................ 14 
5 Adverse event program ................................................................................................. 16 
5.1 
Subject premature Withdrawl........................................................................................ 16 
5.2 
Adverse Events (In accordance with the ICH) ........................................................... 17 
5.3 
Serious Adverse Events .................................................................................................... 17 
6 Insurance and Indemnity ............................................................................................ 17 
7 Reimbursement .............................................................................................................. 17 
8 Data management ......................................................................................................... 18 
9 Statistical analysis ......................................................................................................... 18 
10 Duration of Project ..................................................................................................... 19 
11 Administrative considerations .................................................................................. 19 
11.1 
Changes to the conduct of the study/Amendments to study protocol ................ 19 
11.2 
Premature termination of the study............................................................................ 19 
 
 
 
 

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1 
Overview 
1.1 
Relevance 
Obesity remains a significant public health problem with the prevalence world wide doubling 
and now standing at 600 million adults [1]. We are seeing direct rises in obesity related 
morbidity and mortality, particularly relating to type 2 diabetes, cardiovascular disease and 
obesity related cancers [2]. Treating Obesity remains a challenging prospect and the role of 
pharmacotherapies have been limited by their side effects with surgical interventions proving 
most effective [3]. Bariatric surgery has led the way in terms of effective therapies for obesity 
with 14-25% reduction in body weight as well as improvement in metabolic risk markers and 
reduced mortality compared to control groups [4]. Despite the dramatic effects on calorie 
intake, weight loss and metabolic health, our understanding of mechanisms through which 
bariatric surgery mediates these effects remains limited. The impact of the altered gut 
hormone milieu following Roux-en-Y gastric bypass (RYGB) has raised questions regarding 
the impact of these peptides on food avoidance and food reward patterns. To explore this 
relationship we will conduct a prospective study objectively measuring food preference and 
gut peptide responses in patients undergoing RYGB. 
2 Study Objectives and Design 
2.1 
Objectives 
 
The primary objectives of this study are  
1. Determine the effect of Roux-en-Y gastric bypass (RYGB) surgery on food 
preference using a standardised Buffet meal. 
 
2. Determine if  the changes in food preference following RYGB are mediated through 
changes in gut peptide following surgery. 
2.2 
Design  
The Study will be conducted in two parts. The first phase of the study is an observational 
component where participants who are due to undergo RYGB surgery in addition to a 
matched control group will have their food preference assessed using a standardised 
macronurtient self selection paradigm (MSSP). This process will be undertaken 1 months pre 
and 3, 12 and 24 months post surgical intervention (See figure 1). The control group will be 
studied at matched time points. This will allow determination of the primary outcome, 
whether RYGB surgery alters food preference. Phase two of the trial will focus on 
understanding potential mechanisms responsible for altered food preference. It will take the 
form of a randomised control study whereby subjects following RYGB and controls will be 

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invited to repeat the MSSP after randomly receiving octreotide or saline placebo in a blinded 
crossover fashion. This assessment will take place one year following surgery.  
 
 
Figure 1: Schematic of Study Design 
 
 
 
3 Methodology 
3.1 
Recruitment 
3.1.1 
Participants 
 
1. Patients scheduled to undergo bariatric surgery will be recruited from existing clinics. 
 
2. Healthy free-living individuals will be recruited through community and hospital 
based efforts. 
 
3.1.2 
Inclusion/Exclusion Criteria 
The inclusion and exclusions criteria for the study are outlined below and in order to 
participate in the study patients must comply with these criteria. 
 
Inclusion Criteria 
• 
Age 18 or over 
• 
Surgical and non-surgical groups: 
o Bariatric surgery 
o Controls with no history of bariatric surgery 
• 
Independently mobile 
Figure 1. Each Study visit will include a Buffet lunch, macronutrient self-selection paradigm.  Fasting and 
postprandial blood samples will be collected on all participants. Subjects will be randomised to either 0.9% 
Saline or Octreotide at the 1 year visit crossing over to the other therapy at their second visit.  

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• 
Capacity to consent to participate 
 
Exclusion Criteria 
• 
Age <18 years  
• 
Pre-operatively: Factors impairing ability to consume meal 
o Significant dysphagia 
o Gastric outlet obstruction  
o Anything factor that prevents subjects from eating a meal. 
• 
Post-operatively: Factors impairing ability to consume meal 
o Significant and persistent surgical complications or  
o Anything that prevents subjects from eating a meal. 
• 
Systemic or gastrointestinal condition which may affect food intake or preference 
• 
Pregnancy or lactation 
• 
Active and significant psychiatric illness including substance misuse 
• 
Significant cognitive or communication issues 
• 
Medications with documented effect on food intake or food preference 
• 
History of significant food allergy and certain dietary restrictions 
• 
History of liver disease or pancreatitis (Exclusion from Octreotide) 
• 
History of bradyarrythmia (Exclusion from Octreotide) 
• 
Use of medications with potential serious interactions with Octreotide (Exclusion 
from Octreotide) 
 
3.1.3 
Recruitment procedure 
 
Recruitment of RYGB group  
• 
Subjects referred to the Bariatric surgery service at St Vincents University Hospital 
will be considered for recruitment.  
• 
Subjects will be approached after it is confirmed that they are  suitable candidates for 
RYGB. A member of the clinical team will provide potential participants with a letter 
inviting them to participate in the study.  
• 
Volunteers will be asked to contact the research team if they are interested and a 
screening visit will be scheduled.  
• 
Written information will be sent to individuals interested in taking part prior to the 
screening. 

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• 
At the study visit the participant will have the opportunity to address any concerns or 
questions prior to informed consent being obtained. 
 
Recruitment of RYGB group (non affiliated) 
Recruitment will be opened up to individuals scheduled to undergo bariatric surgery in 
centres other than those outlined above. Posters containing information about the study and 
contact details of the investigators will be distributed to external centres undertaking bariatric 
surgical procedures. Allowing members of the public undergoing bariatric surgery the 
opportunity to opt in to the study if they wish. 
 
Recruitment of Control group 
Recruitment of the control group will be focused on recruiting healthy free living individuals 
who did not have bariatric surgery. These subjects will include those recruited by the 
community and hospital based protocol. 
 
Proposed Recruitment methods 
1. Community based campaign 
Posters outlining the study initiative will be places in public areas including hospital 
waiting rooms, and universities contact information for the research investigator will 
be available. Study information will be circulated internally by email at University 
College Dublin as well as its affiliated hospitals St Vincents University Hospital. 
Potential participants identified through this method will be able to make contact with 
the research investigator and they will receive written information detailing the study 
and be invited to attend a screening visit. If required an open advertisment will be 
placed in national newspaper.  
 
 
2. Primary care campaign 
Posters and information sheets relating to the study will be circulated to GP practices 
in the greater dublin area. We will offer to make a presentation at the UCD and the 
North Dublin City GP training meetings educting primary care physicians on the 
ongoing study initiative. GP/GP trainees will be given information supporting this 
presentation containing contact details for the research investigator that can be given 
to people ientified as potentially suitable in GP practices. Potential subjects identified 
through this method will be able to make contact with the research investigator, 
patients will be invited to attend the hospital for a screening visit. 
 

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3.2 
Study Procedures 
3.2.1 
Food Preference Questionnaire 
At the screening visit, volunteers will be asked to rate their preferences for 72 different food 
stuffs using a Likert scale. The items will be categorised into 6 different groups representing 
depending on their macronutrient content. They will be listed in no particular order. 
Participants will be asked to rate each individual item along the 9 point scale with the 
following anchors: 1 = dislike extremely; 5 = neutral; 9 = like extremely. Responses from the 
Screening Questionnaire will be used to select appropriate foodstuffs for use in a 18 item 
buffet spread, for each given subject, from the stock list of 72 items. The 18 items selected for 
the buffet spread will comprise high fat and low fat options combined with varying 
carbohydrate and protein content.  
 
3.2.2 
Participant Information and Consent 
In advance of the study volunteers will have received a copy of the participant information.  
Any questions and concerns that remain can be discussed with the investigator at the 
screening visit. If the volunteer meets the inclusion criteria and is satisfied to proceed with 
recruitment to the study they will be asked to sign the consent form prior to the initiation of 
any further elements of the study visit. As part of this process every participant will be 
advised of their right to refuse to participate or to withdraw at any time without impediment 
to their medical care in accordance with Good Clinical Practice guidelines. Withdrawal from 
the study can be done at any time by contacting the hospital or research team. If a participant 
chooses to participate, and subsequently withdraws their consent, all blood samples, records 
or footage in storage will be destroyed and the information stored will be deleted so it cannot 
be used again.  
 
3.2.3 
Study Screening Questionnaire 
All volunteers attending who have attended and consented to the screening procedure will 
undertake a screening questionnarie with the assistance of the study doctor. This will outline 
medical history and inclusion and exclusion criteria for the study. 
 
3.2.4 
Anthropometric measures 
In order to minimise variability in the measurements the same investigator will take all 
measurements. At the screening visit the following procedures for anthropometric 
measurement will take place 
 

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• 
Weight measurement 
Study participants will have their weight meaured on a digital eqilibrated scale. The 
measurements will be taken between 10.00 and 11.00 after the volunteer has been 
asked to void. Volunteers will be weighted in their clothing with their shoes off and 
in barefeet or socks . Measurements will be recorded to the nearest 0.1Kg. 
 
• 
Height measurement 
Study participants will have their height measured using a stadiometer. This 
measuremet will be taken in bare feet or socks. Patients will be asked to stand upright 
with their heels, buttocks and occiput touching the backboard of the stadiometer. The 
measuring  arm are of the stadiometer will be brought down to the top of the subjects 
head. Height is recorded to the nearest 0.1cm.  
 
• 
Waist Circumference 
A non-stretch tape measure will be used to measure waist circumference. The 
measurement will be taken with the subject in a standing position with the abdomen 
relaxed, the arms at the sides and the feet together and breathing normally.  The 
measurer faces the subject and places a measuring tape around the subject in a 
horizontal plane, at the mid-point between the lowest rib and the supra iliac crest. The 
measurement should be taken at the end of a normal expiration, ensuring the tape is 
taut around the subject’s waist, without compressing the skin. Waist circumference 
measurements will be taken in duplicate and values will be recorded to the nearest 
0.1cm. The mean value of both measurements will be recorded as the waist 
circumference.  
 
3.2.5 
Venepuncture 
At the study visits bloods will be taken to evlauate both fasting and post prandial gut peptide 
levels.  
 
• 
A blood sample will be drawn approximatley 10ml in total.  
• 
They will be collected in the fasting state and 2 hours after meal initiation.  
• 
All samples will be acquired by a medical doctor with experience in phlebotomy. 
 
• 
2x 5ml EDTA tube  
 

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Collected samples will be transferred to the laboratory and processed accordingly. Plasma 
samples will be centrifuged for 15 minutes at 2500g. The supranatent pipetted into aliquots. 
The aliquots will be labelled with the subject recruitment number, visit number and 
“fasting” or “Post Prandial”. Samples will be stored within a -20 freezer at the clinical 
research centre until processing of the samples commencs. Waste will be disposed of in line 
with hospital was disposal policies.  
 
3.2.6 
Urinary pregnancy test 
Urine specimens will be collected on all women with child bearing potential prior to the 
administration of any drugs which the investigator and participant are blinded to. A spot urine 
sample will be collected from participants, transferred to the biochemistry lab and analysed 
for βHCG according to standardised method in the laboratory. Samples will be labelled with 
the volunteers name, date of birth and medical record number where available. Volunteers 
with an unexpected positive pregnency will be informed by the investigator of the result, 
excluded from the study and referred to their primary care physician for further assessment.  
  
3.3 
Randomisation 
For phase two, the randomised control trial. All subjects recruited will have be assigned an 
anonmysed study number. Randomisation of volunteers to the intervention or placebo group 
will be undertaken using a web based randomisation programme. Subjects will be randomised 
to receive treatment A or B. Treatment A or B will correlate to either Octreotide 1μg/Kg or 
0.01ml/Kg of 0.9% Saline. The buffet meal will be undertaken 60 minutes following the 
administration of either treatment A or B. At the subsequent study visit subjects will receive 
the opposite treatment in a crossover manner. The research investigator and volunteer will be 
blinded to the treatment. Unblinding will only take place at the end of the intervention study 
and data on all subjects has been statistically analysed.  
 
3.4 
Study Drug preparation and administration 
 
Octreotide (Sandostatin® 100μg/ml, Novartis Ireland) 
• 
The drug will be stored in line with manufacturer instructions.   
• 
As the study drug will be blinded to the research investigator, the research nurse will 
be charged with preparing the study drug.  
• 
A dose of 1μg/Kg will be drawn up by the research nurse and labeled with the 
appropriate code Treatment A or Treatment B.  

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• 
The weight used will have been recorded prior to drug administration 
• 
This drug will be administered using a sterile technique to the participant’s 
subcutaneous tissue.  
• 
It will be given 60 minutes prior to the Buffet meal.  
• 
A menstrual history and urinary pregnancy test will be completed on all females of 
child bearing potential prior to the administration of any drug. 
 
0.9% Saline Placebo 
• 
The drug will be stored in line with manufacturer instructions.   
• 
As the study drug will be blinded to the research investigator, the research nurse will 
be charged with preparing the study drug.  
• 
A dose of 0.01ml/Kg will be drawn up by the research nurse and labeled with the 
appropriate code Treatment A or Treatment B.  
• 
The drug will be drawn up using a 1 or 2 ml syringe depending on the volume 
needed.  
• 
The weight used will have been recorded prior to drug administration. 
• 
This drug will be administered using a sterile technique to the participant’s 
subcutaneous tissue.  
• 
It will be given 60 minutes prior to the Buffet meal.  
• 
A menstrual history and urinary pregnancy test will be completed on all females of 
child bearing potential prior to the administration of any drug. 
 
3.5 
Buffet Meal  
The study will take place at the Clinical Research Centre at St Vincents University Hospital. 
The study methodology will follow the paradigm for food preference assessment developed 
and validated by Geiselman et al [1].  
 
Subjects will be provided with a Food preference questionnaire prior to the study visit. This 
will ask patients to hedonically/by preference rate each of approximately 90 common 
foodstuffs of known macronutrient composition on a 9-point Likert scale with the following 
anchors: 1 = dislike extremely; 5 = neutral; 9 = like extremely. This assessment will be 
completed by subjects priot to their screening visit, the data sheet will the collected and 
evaluated by the research investigator. This food preference questionnarie will categorise the 
90 food stuffs into each of the 6 cells highlighted in the table below and in no particular order.  
 

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Responses from the questionnaire will be used to select appropriate foodstuffs for use in an 
18 item buffet spread, for each given subject, from the stock list of 90 items. The 18 items 
selected for the buffet spread will comprise high fat and low fat options combined with 
varying carbohydrate and protein content, as depicted in Table 1. We will endeavour to 
provide each subject with foods to which he/she had an intermediate hedonic response (5 – 7). 
High fat foods given to an individual subject will be paired with a low fat variation of the 
same food; eg high and low fat meat options, high and low fat cheese options. Stock list foods 
are all items which are commercially available and require minimal or no preparation (for 
example slicing fruit, bread or cheese). All food items will be stored and used according to 
manufacturer’s instructions.  
 
Table 1: Macronutrient self-selection paradigm 
 
High Simple Sugar 
High Complex CHO 
Low CHO/High Protein 
High Fat 
Three foods 
Fat > 40% 
Sugar >30% 
Three foods 
Fat >40% 
Comp Carb >30% 
Three foods 
Fat >40% 
Protein >13% 
Low Fat 
Three foods 
Fat <20% 
Sugar >30% 
Three foods 
Fat <20% 
Comp Carb >30% 
Three foods 
Fat <20% 
Protein >13% 
Adapted from Geiselman et al [1]. 
 
 
Subjects will be asked to fast from 22:00 the night before the study visit. Subjects may drink 
water during this period. Volunteers will be asked to abstain from alcohol consumption and 
strenuous exercise for the preceeding 24 hours.  Medications may be taken as per usual, but 
this will be discussed with individual subjects in advance of the study day. Subjects will be 
asked to come to the CRC at 10:30 on the morning of the assessment. On arrival at the CRF, 
study documentation and body anthropometry will be completed.  
 
Each subject will have access to their own individual buffet table, in separate rooms, such that 
subjects cannot observe the selections made by other subjects. Order of foods on the buffet 
spread will be randomised on each study visit. Containers of known weight of the 12 test 
foods will be provided to each subject. Subjects will be provided with written and verbal 
instructions prior to commencing the buffet meal. Volunteers will be instructed that they can 
now eat their meal and consume as much food as they wish in order to feel “comfortably 

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full”. Patients will be made aware that gut hormone responses will not be optimal if they 
don’t reach a state of being comfortably full, eat the foods they like or if they overeat and feel 
unwell. Subjects will be reminded that it is important that they understand and follow these 
instructions, as the blood test for gut hormones will be performed on completion of the meal. 
They may also eat as much of any particular food type they wish and that it is not a 
competition. All subjects will be provided with still bottle water to accompany the buffet 
meal.  
 
Each subject will have access to their own individual buffet table. Subjects will be asked to 
place any mobile electronic devices that they have brought with them into a sealed container 
in their room, with all electronic devices switched off. Reading material and medica sources 
in the form of television or radio will be provided. Subjects will instructed to alert the 
research team when they have finished eating, or should they experience any problems. After 
providing these instructions and answering any questions the subject may have, the 
investigator will then leave the room.  
 
At this point a member of the research team will record the exact quantity of each foodstuff 
chosen by each subject by determining change in test food container weight.  
 
At each of the 12 month visits, patients eligible for randomisation will receive a subcutaneous 
injection of either 1μg/kg octreotide(Sandostatin® 100microgram/ml) or 0.01ml/Kg 0.9% 
saline, in a random sequence. The study meal will be initiated directly after the completion of 
the baseline blood test on study visits not requiring a subcutaneous injection. Where subjects 
have received an injection of octreotide or saline, the meal will be initiated one hour after 
injection to ensure adequate serum concentrations of octreotide have been achieved.  
 
3.6 
Clinical Nutritional Assessment 
All participants will be have an assessment by a trained clinical nutritionist at the end of the 
first study visit. The session include a 45 minute consultation with all participants. It will 
include a review of current dietary preferences followed by a standardised dialogue guiding 
subjects on the priniciples of healthy eating.   
 

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4 
Protocol Overview/Study visit and Event Schedule 
Outlined below is a detailed overview of the study protocol. Table 2 summarises the 
procedures that will be undertaken at each patient visit while Table 3 outlines the basic 
schedule of a typical study visit.  
 
 
Screening Visit 
1. Informed consent 
2. Food preference Qiestionairre 
3. Screening Questionairre and Eligibility Assessment   
 
Study Visit 1: Week -4 
1. Anthropometric assessment: Height, weight, BMI and waist circumference 
2. Fasting Bloods 
3. Buffet Meal 
4. Post prandial bloods 
5. Clinical Nutrition education session  
 
Study Visit 2: Week 12 
1. Anthropometric Assessment: Height, weight, BMI and waist circumference 
2. Fasting Bloods 
3. Buffet meal  
4. Post Prandial Bloods 
 
Study Visit 3: Week 52 
1. Anthropometric Assessment: Height, weight, BMI and waist circumference 
2. Fasting Gut peptide level 
3. Randomisation to treatment A or B (Saline or Octreotide) 
4. Administration of blinded Study drug prior to buffet meal 
5. Buffet meal 
6. Post prandial bloods 
7. Urinary Pregnancy test 
 
Study Visit 4: Week 52 
1. Anthropometric Assessment: Height, weight, BMI and waist circumference 
2. Fasting Gut peptide level 

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3. Administration of blinded study drug prior to buffet meal(A or B determined by 
previous randomization) 
4. Buffet meal 
5. Post prandial bloods 
6. Urinary Pregnancy test 
 
Study Visit 5: Week 102  
1. Anthropometric Assessment: Height, weight, BMI and waist circumference 
2. Fasting Bloods 
3. Buffet meal  
4. Post Prandial Bloods 
5. Discharge from study/Letter to General Practitioner 
 
 
 
Table 2: Schedule of Study Visits and Events 
 
Screening 
Visit 
Visit 1 
Week -4  
Visit 2 
Week 12 
Visit 3 
Week 52 
Visit 4 
Week 52 
Visit 5 
Week 104 
Informed Consent 
X 
X 
 
 
 
 
Height 
 
X 
X 
X 
X 
 
Weight 
 
X 
X 
X 
X 
 
Fat mass 
 
X 
X 
 
X 
 
Blood pressure 
 
X 
X 
X 
X 
X 
Heart rate 
 
X 
X 
X 
X 
X 
Medical History 
 
X 
 
 
 
X 
Fasting Gut Peptides 
 
X 
X 
X 
X 
X 
Post Prandial Gut Peptides 
 
X 
X 
X 
X 
X 
Pregnancy test 
 
X 
X 
X 
X 
X 
Administration of Study 
Drug 
 
 
 
X 
X 
 
Food preference 
Questionnaire 
X 
 
 
 
 
 
Buffet meal 
 
 
X 
 
X 
 
Clinical Nutrition session 
 
X 
 
 
 
 
GP letter 
X 
 
 
 
 
X 
 
 
 
 
 

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5 
Adverse event program 
5.1 
Subject premature Withdrawl 
If a study volunteer fails to complete the study protocol it will be documented in the 
individual case report form. The reason for failure to complete the study will be included in 
the CRF. Study Subjects may be withdrawn for the following reasons 
 
• Adverse Event(s) (AEs)  
• Abnormal laboratory value(s)  
• Protocol violation  
• Subject withdrew consent  
• Lost to follow-up  
• Death  
All patients who withdraw early from the study will have their GP informed in writing that 
their participation in the study is complete. In the event of adverse event, GP’s will be 
informed and arrangements will be made for subjects who have a requirement for ongoing 
medical follow-up as a consequence of an adverse event.  
 
TABLE 3:  General study visit schedule 
Time 
Action 
10:30 
to 
12.00 
Arrive at CRC 
Complete paperwork, questionnaires and collection of anthropometric data 
10.50 
Phlebotomy 1 (fasting pre-meal) 
11.00 
SC injection of octreotide or saline as randomised at 52 week visit 
12.00 
Commence ad libitum buffet meal 
Upon completion of the ad libitum meal 
14.00 
Phlebotomy 2 at 2 hours post meal initiation 
14.15 
End of Visit 

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5.2 
Adverse Events (In accordance with the ICH) 
An adverse event (AE) is defined as “any untoward medical occurrence in a patient or clinical 
investigation subject administered a pharmaceutical product and which does not necessarily 
have to have a causal relationship with this treatment”. The principal investigator (PI) will be 
informed of any adverse events affecting participants within 24 hours of the research 
investigator becoming aware of them.  The suitability of the participant to continue with the 
study will be determined by the PI. All adverse events will be recorded in the CRF and the 
adverse events log contained within the site file. A data safety monitoring committee will be 
establish consisting of a senior physicians. All events will be reported within 7 working days 
and decisions to progress or stop the study will be made in conjunction with the Ethics 
committee. 
 
5.3 
Serious Adverse Events 
A serious adverse event (SAE) or reaction is defined as any untoward medical 
occurrence that: 
• 
results in death  
• 
is life-threatening 
• 
requires inpatient hospitalisation or prolongation of existing hospitalisation 
• 
results in persistent or significant disability/incapacity, or 
• 
is a congenital anomaly/birth defect. 
 
The term "life-threatening" in the definition of "serious" refers to an event in which the 
patient was at risk of death at the time of the event; it does not refer to an event which 
hypothetically might have caused death if it were more severe. The principal investigator (PI) 
will be informed of any adverse events affecting participants within 24 hours of the research 
investigator becoming aware of them.  The suitability of the participant to continue with the 
study will be determined by the PI. All adverse events will be recorded in the CRF and the 
adverse events log contained within the site file. A data safety monitoring committee will be 
establish consisting of a senior physicians. All events will be reported within 7 working days 
and decisions to progress or stop the study will be made in conjunction with the Ethics 
committee. 
6 
Insurance and Indemnity 
Clinical staff will be covered under the institutional Clinical Indemnity Scheme (CIS) 
7 
Reimbursement 
All participants will be reimbursed for travel and parking expenses incurred while 

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participating. Volunteers will not be paid to participate in this study.  
8 
Data management 
 
Data will be collected and stored in both paper and electronic format. Paper data will be filed 
and stored in a locked office at the Clinical Research Centre, St Vincents University Hospital. 
Electronic data will be password encrypted. All data will be handled in line with data 
protection legislation.  
9 
Statistical analysis 
Data will be analysed using GraphPad Prism (version 6.0) for Windows, GraphPad software 
(San Diego, CA, USA) and SPSS® (version 20.0) software (SPSS, Chicago, IL, USA). 
Central tendencies for patient and control group demographics, anthropometric data, caloric 
intake and macronutrient intake will be calculated and expressed using arithmetic mean ± 
standard error of the mean or median (range), as appropriate. Differences in continuous 
variables between surgical and control groups will be calculated using the Student’s t test or 
Mann-Whitney U test for parametric or non-parametric data, respectively. Correlative 
analyses will be performed using the Spearman Rho rank correlation to assess the relationship 
between ad libitum caloric intake and macronutrient intake with peri-operative weight loss 
and anthropometric data. Univariate analysis of factors associated with perioperative and 
post-surgical weight loss will be performed using Student’s t test or one-way ANOVA for 
categorical variables or simple logistic regression for continuous variables. For the 
multivariate analysis, independent variables which were significant on univariate analysis, 
including standard demographic, food intake and food preference, will be entered into a 
multiple logistic regression model with a forward stepwise selection procedure to assess their 
impact on perioperative and post-surgical weight loss. All statistical analyses will be two-
tailed with the threshold of significance set at P < 0.05.  
 
Although the patients will be tested at all of the time points. Sample size has been estimated 
based on Gregersen et al.[2] who suggest that 35 patients will be required per group in an 
unpaired study design to detect a 300kJ difference in overall caloric consumption between 
two groups with a power of 0.8. We anticipate that single-sitting food intake after upper GI 
surgery will be approximately 60-80% that of matched controls. Given a control ad libitum 
caloric intake of approximately 600kcal, this would equate to a 120 – 240kcal difference in 
caloric intake. In addition, differences in preferred food types will be studied.  
 

Food preference following bariatric surgery 
 
June 2016 
  
    
 
 
Version 3 
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10 Duration of Project 
The estimated duration of the study will be 36 months. Screening and recruitment will begin 
in February 2016.  Completion of the study is planned for February 2019. 
 
11 Administrative considerations 
11.1 Changes to the conduct of the study/Amendments to study protocol 
Any and all amendments to the protocol must be agreed upon by the named investigators of 
the study. All protocol amendments must submitted to the institutional ethics committee for 
approval. Informed consent documents must be updated with amendments appropriately and 
submitted with application for protocol revision. Changes to the protocol may not be 
implemented prior to ethical approval unless it is intented to eliminate and immediate hazard 
to the study subject. In this case study sponser and ethics committee must be informed as 
soon as possible of the deviation.  
11.2 Premature termination of the study 
The principal investigator reserves the right to terminate the study at any time. Adequate 
consideration must be given to the protection of all study volunteers on termination of the 
investigation. Subjects will be informed in writing immediately and appropriate follow-up is 
assured.  
 
 
 
 
 
 
References 
 
1. 
Geiselman, P.J., et al., Reliability and Validity of a Macronutrient Self-
Selection Paradigm and a Food Preference Questionnaire. 1997. 63: p. 919-
928. 
2. 
Gregersen, N.T., et al., Reproducibility and power of ad libitum energy 
intake assessed by repeated single meals. Am J Clin Nutr, 2008. 87(5): p. 
1277-81.