Changes in Ingestive Behaviour Following Gastric Bypass

Study Overview
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Brief Summary
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The gastric bypass procedure is known to be one of the most successful treatments for morbid obesity and Type 2 diabetes mellitus, and has been shown to decrease appetite, energy intake, body weight and glycemia both in the short and long term. A number of reports hypothesise that these changes may be driven, at least in part, by positive shifts in food preferences following surgery. However, findings are drawn from self-reported dietary intakes which are beset with measurement bias, thus precluding definite conclusions. The current work aims to directly observe food intake to test the hypothesis that after gastric bypass food intake changes in a manner which leads to beneficial outcomes on body weight when compared to weight stable control participants. Patients (n=32) with a planned gastric bypass procedure will be recruited from Phoenix Health (Ireland and England) and Letterkenny University Hospital (Ireland), alongside control participants (n=32) with no planned weight loss. All subjects will attend the Human Intervention Studies Unit (HISU), Ulster University on five occasions (1-month pre-surgery and 3, 12, 24 and 60 months post-surgery, with controls being time-matched). Study visits will be fully residential involving two overnight stays within the facility during which participants' 24-hour food intake will be covertly measured (7am-11pm Day 2 and breakfast Day 3) and the following procedures undertaken; basal metabolic rate, body composition, bone health, assessment of liking/wanting high fat foods and post-meal gut hormone responses. On each study visit participants will have ad lib access to a range of foods of varying macronutrient composition and which are compatible with their stated food preferences (assessed prior to the start of the study). Changes in all ingestive behaviours will be evaluated over time as compared to the control participants.

Official Title
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Changes in Ingestive Behaviour Following Gastric Bypass

Conditions
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Morbid Obesity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: >18 years Planned gastric bypass surgery (patients only) No planned weight loss/gain (controls only) Exclusion Criteria: Patients Significant dysphagia, gastric outlet obstruction or any other factor which prevents consumption of a meal Systemic or gastrointestinal condition which may affect food intake or preference Pregnancy / lactation Significant food allergy or dietary restriction Medication with documented effect on food intake or food preference Any other physical or psychological condition which would affect the outcome of the study as determined by Phoenix Health care team. Controls Medication with documented effect on food intake / preference or study outcomes Pregnancy / lactation Significant food allergy or dietary restriction Undertaking a weight-loss programme or planning to.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Gastric bypass patients<br>Patients planned to undergo Gastric bypass procedure. Patients will be assessed -1 month, 3-, 24-, 48- and 60 months post surgery. | |
| Healthy controls<br>Healthy controls with no planned weight loss/gain. Control participant assessments will be time-matched with patients. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Food intake | Total energy density (kJ / gram) | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total energy intake | 24-hour intake (kJ) | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Relative macronutrient intake | % contribution of macronutrient to energy intake | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Food preferences | Explicit and implicit food preferences measured by the Leeds Food Preference Questionnaire | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Eating occasion size | Grams and kJ over 24 hour period | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Eating speed | g/min and kJ/min over 24 hour period | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Meal frequency | Defined as a continuous period of feeding terminated with a pause >5mins | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Basal Metabolic Rate | Measured by indirect calorimetry | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Percentage body fat | Measured by dual X-ray absorptiometry | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Percentage lean weight | Measured by dual X-ray absorptiometry | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Bone health | Measured by dual X-ray absorptiometry | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Serum lipid profile |  | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Plasma micronutrient status |  | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 
| Serum C-Reactive Protein |  | Change from pre-surgery (-1 month) at 3-, 24-, 48- and 60-months post surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gastric bypass, Morbid obesity, Food choice, Ingestive behaviour, Food preference