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Completed

NCT Number: NCT01531738

Investigation of the Effects of Bariatric Surgery on Taste Reward in Humans

The investigators hypothesize that some of these changes in the reduced appetite after surgery may be due to alterations in taste. The aim is to compare obese patients before and after bariatric surgery (gastric bypass and banding) to define the reward value of sweet, fatty and vegetable/fruit taste in obese individuals, and how this changes after surgery.

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Key information

Conditions

Obesity Behavior Body Weight Feeding Behavior Food Preferences Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Imperial Weight Centre, Imperial College London

London, W6 8RF, United Kingdom

About this study

Severe obesity is associated with excessive food eating and appetite. Bariatric surgery (also known as 'obesity surgery' or 'weight loss surgery') is a well known treatment for severely obese individuals. The way in which these operations achieve weight loss is not fully understood. The investigators hypothesize that some of these changes in the reduced appetite after surgery may be due to alterations in taste. The aim is to compare obese patients before and after bariatric surgery (gastric bypass and banding) to define the reward value of sweet, fatty and vegetable/fruit taste in obese individuals, and how this changes after surgery.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • BMI of 18-25 for normal weight volunteers
  • BMI of >30 for obese patients

Exclusion criteria

  • Pregnancy
  • breast feeding
  • substance abuse
  • consumption of more than 3 alcoholic units per day
  • severe psychiatric illness
  • lack of understanding of test instructions
  • diabetes mellitus
  • chronic medical conditions making a general anaesthetic unsafe
  • allergy to stimulus ingredients
  • active smoking

Treatment and study plan

Primary outcomes

  1. Breakpoints as Assessed by Change in the Number of Mouse Clicks in the Last Completed Ratio

    Time frame: 2 weeks pre and 8-12 weeks post operatively for surgical patients or on two occasions 10-14 weeks apart for normal weight control group

    Patients were placed in front of a computer screen and a plate of 20 chocolate candies. The following prompt appeared on the screen: "You can earn food by clicking on the mouse button. Click as much or as little as you like. When you no longer want to continue, press the spacebar to stop the session."Upon completion of each ratio a message box appeared on the screen: "You have earned food. Enjoy your reward and after you have swallowed it completely you may click on OK to continue with the programme."After ingesting the reward, the patients pressed the OK button in the message box only if they wished to progress to the next ratio to obtain another chocolate candy. The starting ratio was 10 clicks with a geometric increment of 2 (i.e., 10, 20, 40, 80, and so on). When the effort of pressing the mouse button was greater than the rewarding value of the chocolate candy, patients pressed on the space bar to terminate the session. This indicated that the breakpoint was reached.

Secondary outcomes

  1. Hunger

    Time frame: 2 weeks pre and 8-12 weeks post operatively for surgical patients or on two occasions 10-14 weeks apart for normal weight control group

    Visual Analogue Scale ratings of hunger. The scale is 100mm line with two anchors at each end. Scores are recorded by making a handwritten mark that represents a continuum between "not hungry at all" and "Extremely hungry." The score of 0 represents least hunger. The score of 100 represents extreme hunger.

    change in hunger levels quantified by a 100mm visual analogue scale

  2. Body Mass Index

    Time frame: 2 weeks pre and 8-12 weeks post operatively for surgical patients or on two occasions 10-14 weeks apart for normal weight control group

    change in BMI will be quantified based on the participants weight in kilograms and height in meters

Sponsors and collaborators

Lead sponsor

Imperial College London

Other

Collaborators

  • Medical Research Council

Registry information

Important dates

Study start
2010
Primary completion
2012
Study completion
2012
First posted
Feb 13, 2012
Registry last updated
Nov 16, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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