The Effects of Current Treatments of Obesity on Food Preferences, Gut Hormones, Bile Acids and Hepatic Glucose Output in Humans.
Conditions: Obesity, Type 2 Diabetes Mellitus
Sponsor: Imperial College London

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
1 
 
 
 
 
 
 
 
 
     
 
 
The effects of current treatments of obesity on food preferences, gut hormones, bile 
acids and hepatic glucose output in humans. 
 
 
Version 4, 12/06/2013 
 
MAIN SPONSOR: Imperial College London 
 
FUNDERS: The Moulton Charitable Foundation 
 
STUDY COORDINATION CENTRE: Imperial Weight Centre, 9E Room 8, Charing Cross 
Hospital, Fulham Palace Road, London W6 8RF. 
NRES reference:  
 
Protocol authorised by: Dr Carel le Roux, Reader and Honorary Consultant in 
Metabolic Medicine 
Date: 12/06/2013 
 
 
Signature: 
 
 
 
 
 
 
 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
2 
 
 
Study Management Group 
Chief Investigator: Dr Carel  le Roux 
Co-investigators: Dr Alexander Miras, Mr Torsten Olbers, Prof David Russell Jones, Mr 
Richard Welbourne, Mr Ji Tham, Prof Nadey Hakim, Prof Margot Umpleby, Dr Fariba 
Shojaee-Moradie, Dr Roselle Herring, Dr Tony Goldstone, Mr Ameet Patel, Miss Beth 
Murgatroyd, Miss Werd Al Najim. 
 
Study Management: Dr Carel le Roux 
 
Study Coordination Centre  
For general queries, supply of study documentation, and collection of data, please contact: 
Study Coordinator: Dr Carel le Roux 
Address: Imperial Weight Centre, 9E Room 8, Charing Cross Hospital, Fulham Palace Road, 
London W6 8RF. 
Tel: 020 8383 5970 
E-mail: c.leroux@imperial.ac.uk 
Clinical Queries 
Clinical queries should be directed to Dr Carel le Roux who will direct the query to the 
appropriate person 
Sponsor 
Imperial College London is the main research Sponsor for this study. 
For further information regarding the sponsorship conditions, please contact the Head of 
Regulatory Compliance at: 
Joint Research Office 
Sir Alexander Fleming Building 
Imperial College 
Exhibition Road 
London SW7 2AZ 
Tel: 020 7594 1188 
Fax: 020 7594 1792 
 
Funder:  
The Moulton Charitable Foundation 
 
This protocol describes this study and provides information about procedures for entering 
participants. Every care was taken in its drafting, but corrections or amendments may be 
necessary. These will be circulated to investigators in the study. Problems relating to this 
study should be referred, in the first instance, to the Chief Investigator. 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
3 
This study will adhere to the principles outlined in the NHS Research Governance 
Framework for Health and Social Care (2nd edition). It will be conducted in compliance with 
the protocol, the Data Protection Act and other regulatory requirements as appropriate. 
 
Table of Contents                                                                       Page 
1. INTRODUCTION                                                       
 
4 
1.1 BACKGROUND   
 
 
 
 
 
4 
2. STUDY OBJECTIVES  
 
 
 
 
 
5 
3. STUDY DESIGN   
 
 
 
 
 
5 
3.1 STUDY OUTCOME MEASURES  
 
 
 
6 
4. PARTICIPANT ENTRY  
 
 
 
 
 
7 
4.1 INCLUSION CRITERIA   
 
 
 
 
7 
4.2 EXCLUSION CRITERIA   
 
 
 
 
7 
5. ADVERSE EVENTS  
 
 
 
 
 
7 
5.1 DEFINITIONS  
 
 
 
 
 
 
7 
5.2 REPORTING PROCEDURES  
 
 
 
 
7 
6. ASSESSMENT AND FOLLOW-UP  
 
 
 
8 
7. STATISTICS AND DATA ANALYSIS  
 
 
 
8 
8. REGULATORY ISSUES   
 
 
 
 
8 
8.1 ETHICS APPROVAL  
 
 
 
 
 
8 
8.2 CONSENT  
 
 
 
 
 
 
8 
 
8.3 CONFIDENTIALITY  
 
 
 
 
 
9 
 
8.4 INDEMNITY  
 
 
 
 
 
 
9 
 
8.5 SPONSOR  
 
 
 
 
 
 
9 
 
8.6 FUNDING  
 
 
 
 
 
 
9 
8.7 AUDITS AND INSPECTIONS  
 
 
 
 
9 
9. STUDY MANAGEMENT   
 
 
 
 
9 
10. PUBLICATION POLICY   
 
 
 
 
9 
11. REFERENCES   
 
 
 
 
 
9 
12. APPENDIX 
 
 
 
 
 
 
11 
 
  
 
 
 
 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
4 
 
 
 
1. Introduction 
1.1 Background 
 
Obesity has reached epidemic proportions and is the biggest challenge our health care 
systems have to face both in terms of its personal and social deleterious consequences.  
 
Lifestyle interventions including alterations in diet and increases in physical activity are 
effective in the short term only [1, 2]. Few pharmacological agents have been used for 
weight loss but unfortunately even fewer have survived the test of time.  
 
The most effective treatment modality for obesity is obesity surgery which has sustainable 
weight loss effects over a 15 year period at least and also offers a mortality benefit [3]. The 
most popular surgical procedures used worldwide include the gastric bypass, gastric 
banding and the sleeve gastrectomy. These procedures cause weight loss primarily by 
reducing hunger and increasing satiety [4]. Bile has been implicated in the release of satiety 
gut hormones as well as a mediator of the metabolic effect of the operation [5]. 
 
In the last few years new pharmacological agents, also called Incretin therapies, have been 
introduced for the treatment of Type 2 Diabetes Mellitus. Exenatide, an Exendin 4 analogue 
and Liraglutide, a GLP-1 analogue, stimulate insulin secretion from the pancreas as part of 
their glucose reducing properties. They do however also have impressive weight reducing 
effects which is something unusual in the field of diabetes pharmacotherapy. They reduce 
food intake through their actions in the hypothalamus, by causing nausea -at least initially- 
and by reducing gastric emptying thus creating a sensation of fullness [6]. 
 
The EndoBarrier is fundamentally a gastrointestinal impermeable barrier or a gastric sleeve 
that prevents food from coming in contact with the intestinal wall.  The device is implanted 
endoscopically through the mouth and is placed in such a way that it lines the first two feet of 
the small intestine. This helps to prevent easy absorption of food as long as it remains in the 
sleeve and has huge impact on the patients intake of nutrients and calories [7]. Research in 
animal models suggests that when the duodenum and proximal jejunum are surgically 
bypassed, the mid and distal jejunum is stimulated by undigested nutrients. The jejunum 
then signals to the brain to reduce hepatic glucose output [8]. In clinical studies, the 
Endobarrier improves fasting and post prandial glycaemia via a reduction in insulin 
resistance, as measured by HOMA-IR (Homeostatic model assessment-Insulin Resistance) 
[9]. This is thought to be mediated by bile acids [10]. The HOMA-IR is a surrogate and 
imprecise marker of hepatic insulin resistance and the hyperglycaemic euglycaemic 
clamping method is the gold standard. Bile acids are believed to be key mediators behind 
these metabolic improvements. By confirming that the bypass of the proximal bowel reduces 
hepatic insulin resistance and hepatic glucose output, we can then begin to understand the 
mechanisms through which this device (and eventually bariatric surgery) improves 
glycaemia and even food preferences through the signalling of the jejunum to the brain. 
 
Anecdotal evidence from the Obesity and Diabetes clinics and also limited data from the 
literature, suggest that patients after obesity surgery [11-15] but also patients on incretin 
therapies not only reduce their total intake of calories but also change the macronutrient 
composition of their diets. The most consistent change patients describe includes a 
reduction in the proportion of fat and sugars in their diets and an increase in the 
consumption of fruit and vegetable. Potential mechanisms causing this impressive shift in 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
5 
food preferences include alterations in sensory perception of these macronutrients (i.e. 
changes in taste) or post ingestive effects. Elucidation of these mechanisms can lead to 
safer and more effective targeted pharmacological and surgical treatments for obesity. 
 
There is lack of prospective studies comparing the above obesity surgical procedures and 
their effects on food preferences, satiety, gut hormones, bile acids and hepatic glucose 
output. There is no data on incretin therapies and food preferences in humans [16].  
 
2. Study Objectives 
 
The objective of this study is to investigate the effects of obesity surgical procedures and 
incretin therapies on food preferences, satiety, gut hormones, bile acids and hepatic glucose 
output in overweight and obese patients.   
 
3. Study Design 
 
This is a prospective observational controlled trial. 400 overweight and/or obese patients 
(Body Mass Index ≥ 30 Kg/m2) will be recruited from the Imperial College NHS Trust, Royal 
Surrey County Hospital, Musgrove Park Hospital, King’s College Hospital and private obesity 
and/or Diabetes clinics and studied prospectively for 1 year. The study groups will be as 
follows (n=50 per group): 
 
Group A: Patients due to undergo gastric bypass 
Group B: Patients due to undergo gastric banding 
Group C: Patients due to undergo sleeve gastrectomy 
Group D: Patients due to undergo endoscopic Endobarrier insertion 
Group E: Patients due to be commenced on Exenatide 
Group F: Patients due to be commenced on Liraglutide 
Group G (control): Patients due to be commenced on a lifestyle intervention programme 
Group H (control): Patients due to have non bariatric surgery (i.e. cholecystectomy) or an elective 
diagnostic endoscopy 
 
As part of routine care these patients will be seen by a qualified doctor or 
dietician/nutritionist/diabetes specialist nurse (DSN) before and after intervention. Patients in 
control group G and H will be asked to use a low calorie diet either as part of their routine 
care or for research purposes only. Patients will be asked to prospectively complete food 
diaries on three consecutive days which are representative of their usual dietary intake and 
have a dietary assessment. This assessment will take 30-45 minutes and will take the form 
of a short discussion of dietary habits and will include completion of eating behaviour 
questionnaires (assessing dietary/personality traits including restraint, disinhibition, external 
eating and emotional eating).  The first dietary assessment will be completed before the 
intervention and at 1 month, 3 months, 6 months and 12 months after intervention. Total 
energy intake and macronutrient composition comparisons pre and post intervention will 
form the basis of our analysis. 
 
20 patients in each group will undergo more detailed measurements of food intake, hunger, 
satiety, gut hormones and bile acids. The research protocol will be the similar to that 
previously published by the Department of Metabolic Medicine, Imperial College, London.  
Participants will be fasted for 12 hours overnight and will attend for the study on 5 occasions.  
On each occasion venous blood samples will be taken and visual analogue scores will be 
measured over a 3 hour period using previously published methodology (Appendix Table 1: 
Test Periods).  Samples or sample containers will be anonymised before collection but will 
be traceable back to the individual patients. Urine will be collected once. A qualified medical 
doctor will insert a venepuncture cannula into the arm of the patient and 5ml blood will be 
withdrawn at baseline, 15, 30, 60, 90, 120, 150 and 180 minutes following ingestion of a 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
6 
standard 400kcal meal as below (Appendix Table 2: Protocol of each Test).  After each 
sample the cannula will be flushed with saline to keep it patent.  The protocol will be carried 
out 5 times per patient, pre intervention, 2, 7-30 days, 3 and 6-12 months post intervention.  
Plasma samples will be analysed for gut hormones as well as for primary bile acids and 
lipids. An extra blood and urine test will be obtained 1 month after treatment but not 
followed by a meal test. 
 
Ten to twenty patients in each group (different from those taking part in the meal studies) 
will undergo measurements of hepatic glucose output/insulin resistance through 
euglycaemic hyperinsulinaemic clamps (Metabolic Study). Patients will be studied up to 
4 times: at baseline, within 1-2 weeks of a low calorie diet and within 1-2 weeks after 
their weight loss treatment, whilst on the same liquid diet. The low calorie liquid diet is 
nutritious and contains all appropriate macronutrients. Such diets are frequently used as 
part of obesity interventions to reduce weight and risk. Patients will provide the 
investigators with a detailed food diary of their food consumption for this period. The final 
study will take place 6-12 months after the weight loss treatment whilst patients are on 
their normal diet. Throughout this period, the investigators will be in close contact with 
those patients who have diabetes to optimise their glucose control through adjustments 
of their glucose-lowering medications. Our unit has a track record in safe and effective 
glycaemic management before and after weight loss interventions [17]. 
 
Patient will attend the investigation unit after an overnight fast. They will be weighed and 
an intravenous cannula will be inserted in the antecubital of each arm. The first cannula 
will be used for infusions and the other for blood sampling. Participants will be asked to 
provide a urine sample that will be tested for albumin creatinine ratio and 
metabolic/inflammatory markers. If blood glucose levels are high on arrival an insulin 
infusion will be started to attain a stable glucose level (4.0 -6.0 mmol/l) prior to 
commencement of the hyperinsulinaemic euglycaemia clamp (Time -120). A priming 
dose of a stable isotope tracer will be given directly into the cannula and stable isotope 
of glucose will be infused at -120 to +120 minutes to measure the rate of hepatic glucose 
production. At 0 minutes a low dose insulin infusion (0.3-0.5 mU/kg/min) will be 
commenced and a variable rate infusion of 20% dextrose “spiked” glucose tracer will be 
given to maintain the glucose level to 4.0-6.0 mmol/l. Blood samples of 4-13 mls each 
will be taken to measure glucose, insulin, c-peptide, glucagon, lipids and gut hormones 
at -120, -20, -15, -10, -5, 0, +30, +60, +90, +100, +110, +120, +150. At +120 minutes the 
insulin infusion and glucose tracer infusion will be stopped. At the same time points 
participants will be asked to complete appetite visual analogue scales. Participants will 
be fed and glucose infusion continued for a further 20 minutes to prevent 
hypoglycaemia.  Depending on the patient’s blood glucose control on arrival, the 
maximum duration of the whole visit will be up to 7 hours. 
 
Blood samples will be centrifuged and the separated plasma kept in a - 20°C freezer. The 
isotopic enrichment of plasma glucose will be determined by gas chromatography mass 
spectrometry (GCMS) at the Wolfson Centre for Translational Research, Postgraduate 
Medical School, University of Surrey. 
 
The stable labelled isotope tracers [6,6 2H2] is not a drug, but a naturally occurring 
metabolite which has been labelled with a stable, i.e. non-radioactive label. Stable 
isotope tracers are widely used in metabolic research by groups throughout the UK and 
worldwide. All labelled isotope tracers are ordered from Cambridge Isotopes Ltd through 
their UK suppliers CK gases Ltd. They are prepared as sterile solutions suitable for 
intravenous use by the Pharmacy Production Unit at Guys & St. Thomas’ NHS Trust to 
ensure they are safe for the participants. The products are supplied with the appropriate 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
7 
certificate of analysis and MSDS. We have used the same manufacturer to be sure of 
the quality of the products and the supporting documentation.  
 
 
3.1 
Study outcome measures 
 
Primary Endpoint 
The primary outcome measure will be total energy intake and dietary composition in terms 
macronutrient proportions (fat, saturated fat, carbohydrates, sugars, fibre, protein and salt). 
 
Secondary outcomes 
The secondary outcome measures will be the ratings of hunger and satiety, gut hormones, 
bile acid and lipid levels before and after a standardised meal. In the clamp studies, the 
outcome will also be hepatic glucose output and insulin resistance.  
 
 
4. Participant Entry 
 
4.1 Inclusion criteria 
Adult patients with overweight or obesity (BMI ≥30 Kg/m2) who are having a weight loss 
intervention. 
 
4.2 Exclusion criteria 
None. 
 
5. Adverse events 
5.1 Definitions 
Adverse Event (AE): any untoward medical occurrence in a patient or clinical study subject. 
Serious Adverse Event (SAE): any untoward and unexpected medical occurrence or effect 
that: 
 
Results in death 
 
Is life-threatening – refers to an event in which the subject 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 
 
Requires hospitalisation, or prolongation of existing inpatients’ hospitalisation 
 
Results in persistent or significant disability or incapacity 
 
Is a congenital anomaly or birth defect 
 
Medical judgement should be exercised in deciding whether an AE is serious in other 
situations. Important AEs that are not immediately life-threatening or do not result in death or 
hospitalisation but may jeopardise the subject or may require intervention to prevent one of 
the other outcomes listed in the definition above, should also be considered serious. 
 
5.3 Reporting procedures 
All adverse events should be reported. Depending on the nature of the event the reporting 
procedures below should be followed. Any questions concerning adverse event reporting 
should be directed to the Chief Investigator in the first instance. 
 
5.3.1 Non serious AEs 
All such events, whether expected or not, should be recorded. 
 
5.3.2 Serious AEs 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
8 
An SAE form should be completed and faxed to the Chief Investigator within 24 hours. 
However, relapse and death due to non-obesity or diabetes related causes, and 
hospitalisations for elective treatment of a pre-existing condition do not need reporting as 
SAEs. All SAEs should be reported to the Charing Cross Hospital REC where in the opinion 
of the Chief Investigator, the event was: 
 
‘related’, i.e. resulted from the administration of any of the research procedures; and 
 
‘unexpected’, i.e. an event that is not listed in the protocol as an expected occurrence 
 
Reports of related and unexpected SAEs should be submitted within 15 days of the Chief 
Investigator becoming aware of the event, using the NRES SAE form for non-IMP studies. 
Local investigators should report any SAEs as required by their Local Research Ethics 
Committee, Sponsor and/or Research & Development Office. 
Contact details for reporting SAEs 
Fax: 02083830673, attention Dr Carel le Roux 
Please send SAE forms to: Dr Carel le Roux, Imperial Weight Centre, 9E Room 8, 
Charing Cross Hospital, Fulham Palace Road, London W6 8RF. 
Tel: 07970719453 (Mon to Fri 09.00 – 17.00) 
6. Assessment and Follow Up 
Assessment will take place through the use of dietary assessments, standardized meal tests 
and metabolic clamp tests. The dietary assessments will be completed once before and 1, 3, 
6 and 12 months post all interventions. The meal tests will take place once before and 2 
days, 7-30 days, 3 and 12 months after intervention. The metabolic study will be performed 
4 times: at baseline, within 1-2 weeks of a low calorie diet and within 1-2 weeks after 
their weight loss treatment, whilst on the same liquid diet. The final study visit will take 
place 6-12 months after the weight loss treatment whilst patients are on their normal 
diet.  
 
7. Statistics and Data Analysis 
The groups will be allocated at random and thus the distribution of the data should be 
similar. A student's t-test will be used to compare the two groups for the primary and 
secondary end points. Descriptive statistics (proportions, mean, medians, standard errors 
and ranges) will be computed for all baseline variables with 95% CI using either exact 
binomial confidence intervals or t-confidence intervals for continuous outcomes (after 
appropriate transformation of the outcome to symmetry). All tests will be conducted at 
alpha=0.05. Previous studies investigating the effects of obesity surgery on macronutrient 
intake have recruited 50 patients per group and had power to detect significant differences. 
This type of study has never been performed with incretin pharmacotherapies and therefore 
will serve as a pilot for the investigation of the effects of this treatment intervention. The 
standardised meal study will have 80% statistical power to detect a difference of 5 pmol/L 
from the expected mean PYY level of 30 pmol/L when the usual standard deviation is 8 
pmol/L, the sample size 20 subjects and the alpha error level 5%. This power calculation has 
been based on previous published results by the same group.  Therefore 20 patients in each 
group are needed.   
 
For the metabolic study, the endpoint is the minimum endogenous glucose production rate. 
Based on the HOMA-IR results from the only published study on patients having undergone 
the Endobarrier procedure, we will have a power of 81% at a p level of <0.05 if 6 patients 
complete the study.  To allow for patients dropping out, a maximum of 10 patients will be 
enrolled to ensure 6 patients complete the study.  
8. Regulatory Issues 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
9 
 
8.1 Ethics approval 
The Chief Investigator has obtained approval from the West London 2 Research Ethics 
Committee. The study will be conducted in accordance with the recommendations for 
physicians involved in research on human subjects adopted by the 18th World Medical 
Assembly, Helsinki 1964 and later revisions. 
 
8.2 Consent 
Consent to enter the study will be sought from each obese patients and healthy volunteers 
only after a full explanation has been given, an information leaflet offered and time allowed 
for consideration. Signed participant consent will be obtained. The right of the participant to 
refuse to participate without giving reasons will be respected. After the participant has 
entered the study the clinician remains free to give alternative treatment to that specified in 
the protocol at any stage if he/she feels it is in the participant’s best interest, but the reasons 
for doing so should be recorded. In these cases the participants remain within the study for 
the purposes of follow-up and data analysis. All participants are free to withdraw at any time 
from the protocol treatment without giving reasons and without prejudicing further treatment. 
 
8.3 Confidentiality 
The Chief Investigator will preserve the confidentiality of participants taking part in the study 
and is registered under the Data Protection Act. 
 
8.4 Indemnity 
Imperial College London holds negligent harm and non-negligent harm insurance policies 
which apply to this study. 
8.5 Sponsor 
Imperial College London will act as the main sponsor for this study. Delegated 
responsibilities will be assigned to the NHS trusts taking part in this study. 
8.6 Funding 
The Moulton Charitable Foundation. 
 
8.7 Audits and inspections 
The study may be subject to inspection and audit by Imperial College London under their 
remit as sponsor and other regulatory bodies to ensure adherence to GCP and the NHS 
Research Governance Framework for Health and Social Care (2nd edition). 
 
9. Study Management 
The day-to-day management of the study will be co-ordinated through Dr Carel le Roux. 
 
10. Publication policy 
Publication to be aimed for medical conferences and peer-reviewed journals. 
 
11. References 
1. 
Buchwald, H., et al., Bariatric surgery: a systematic review and meta-analysis. JAMA, 2004. 
292(14): p. 1724-37. 
2. 
Sjostrom, L., et al., Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric 
surgery. N Engl J Med, 2004. 351(26): p. 2683-93. 
3. 
Sjostrom, L., et al., Effects of bariatric surgery on mortality in Swedish obese subjects. N Engl 
J Med, 2007. 357(8): p. 741-52. 
4. 
le Roux, C.W., et al., Gut hormone profiles following bariatric surgery favor an anorectic 
state, facilitate weight loss, and improve metabolic parameters. Ann Surg, 2006. 243(1): p. 
108-14. 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
10
5. 
Patti, M.E., et al., Serum bile acids are higher in humans with prior gastric bypass: potential 
contribution to improved glucose and lipid metabolism. Obesity (Silver Spring), 2009. 17(9): 
p. 1671-7. 
6. 
Bradley, D.P., R. Kulstad, and D.A. Schoeller, Exenatide and weight loss. Nutrition, 2010. 
26(3): p. 243-9. 
7. 
Schouten, R., et al., A multicenter, randomized efficacy study of the EndoBarrier 
Gastrointestinal Liner for presurgical weight loss prior to bariatric surgery. Ann Surg, 2010. 
251(2): p. 236-43. 
8. 
Breen, D.M., et al., Jejunal nutrient sensing is required for duodenal-jejunal bypass surgery to 
rapidly lower glucose concentrations in uncontrolled diabetes. Nat Med, 2012. advance 
online publication. 
9. 
Cohen RV, et al. Endoscopic Duodenal-Jejunal Bypass: Effect on Insulin Sensitivity in Mildly 
Obese Diabetic Subjects. in 72nd Scientific Sessions American Diabetes Association. 2012. 
Philadelphia, USA. 
10. 
Kars, M., et al., Tauroursodeoxycholic Acid may improve liver and muscle but not adipose 
tissue insulin sensitivity in obese men and women. Diabetes, 2010. 59(8): p. 1899-905. 
11. 
Thomas, J.R., F. Gizis, and E. Marcus, Food selections of Roux-en-Y gastric bypass patients up 
to 2.5 years postsurgery. J Am Diet Assoc, 2010. 110(4): p. 608-12. 
12. 
Kenler, H.A., R.E. Brolin, and R.P. Cody, Changes in eating behavior after horizontal 
gastroplasty and Roux-en-Y gastric bypass. Am J Clin Nutr, 1990. 52(1): p. 87-92. 
13. 
Olbers, T., et al., Body composition, dietary intake, and energy expenditure after laparoscopic 
Roux-en-Y gastric bypass and laparoscopic vertical banded gastroplasty: a randomized 
clinical trial. Ann Surg, 2006. 244(5): p. 715-22. 
14. 
Halmi, K.A., et al., Appetitive behavior after gastric bypass for obesity. Int J Obes, 1981. 5(5): 
p. 457-64. 
15. 
Brown, E.K., E.A. Settle, and A.M. Van Rij, Food intake patterns of gastric bypass patients. J 
Am Diet Assoc, 1982. 80(5): p. 437-43. 
16. 
Vedtofte, L., et al., Liraglutide, but not vildagliptin, restores normoglycaemia and insulin 
content in the animal model of type 2 diabetes, Psammomys obesus. Regul Pept, 2010. 
160(1-3): p. 106-14. 
17. 
Fenske, W.K., et al., Can a protocol for glycaemic control improve type 2 diabetes outcomes 
after gastric bypass? Obes Surg, 2012. 22(1): p. 90-6. 
 
 
 
 
 
 
 
 
 
 
 
 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
11
Appendix 
Table 1: Testing time points  
Frequency test performed 
Test 
Preoperatively 
400kcal standard meal plus venous blood sampling 
and visual analogue scores 
Day 2 
400kcal standard meal plus venous blood sampling 
and visual analogue scores 
Day 7-30) 
400kcal standard meal plus venous blood sampling 
and visual analogue scores 
3 months 
400kcal standard meal plus venous blood sampling 
and visual analogue scores 
6-12 months 
400kcal standard meal plus venous blood sampling 
and visual analogue scores 
 
Table 2: Meal study protocol 
Time 
Intervention 
Outcome measured 
Outcome measured 
0’ 
400kcal standard 
meal 
Venous blood 
sampling 5ml 
Visual analogue score 
15’ 
 
Venous blood 
sampling 5ml 
 
30’ 
 
Venous blood 
sampling 5ml 
 
60’ 
 
Venous blood 
sampling 5ml 
Visual analogue score 
90’ 
 
Venous blood 
sampling 5ml 
 
120’ 
 
Venous blood 
sampling 5ml 
Visual analogue score 
150’ 
 
Venous blood 
sampling 5ml 
 
180’ 
 
Venous blood 
sampling 5ml 
Visual analogue score 
 
 
 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
12
Diagrammatic representation of the metabolic study protocol 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
13
Metabolic study protocol 
Time (min) 
Action 
Blood sampling (volume) 
 
 
Glucose  
Conc and Enrichment 
(1ml) 
Insulin 
(Serum) 
(3ml) 
Glucagon 
(Serum) 
(2ml) 
c-peptide/lipids/Gut 
hormones  
(Serum)  
(7ml) 
– 120 to 0 
Sliding scale insulin infusion 1 U/ml (0.1 - 6 ml/h) 
15 minute interval blood glucose monitoring; maintenance of glucose at 4.0 – 6.0 mmol/l; 
-120 
X 
x 
-120 to +120 Start 6,6 2H2 glucose infusion  
-20 
X 
x 
-15 
X 
x 
-10 
X 
x 
-5 
X 
x 
0 
X 
x 
x 
x 
0-240 
Low dose insulin infusion 0.3-0.5 mU/kg/min 
Initiation of variable infusion of 20% glucose spiked with 2H2 glucose; maintenance of clamp 
glucose at 4.0 – 6.0 mmol/ l 
+30 
X 
x 
x 
x 
+60 
X 
x 
+90 
X 
x 
x 
x 
+100 
X 
x 
+110 
X 
x 
+120 
Stop isotope 
and insulin          
Food will be 
given to the 
patient 
X 
x 
x 
x 
+150 
X 
x 
x 
x 
             .  
 

 
 REC reference 11/LO/0322, Version 4, 12/06/2013 
 
14