Among all the existing ways to treat obesity (lifestyle, pharmacological), Roux-en-Y gastric bypass (RYGB) surgery is currently the most effective. It results in long term weight loss maintenance, significant remission of obesity-related comorbidities and decreased overall mortality. It also induces changes in gastrointestinal hormones responses, with an increase of anorexigenic hormones GLP-1, and PYY. Although successful, the mechanisms for RYGB-induced weight loss are not completely understood. The RYGB does result in increased satiation, decreased calorie intake and decreased preferences for sweet and fatty foods. Previous work from our lab has shown using progressive ratio task (PRT) that RYGB specifically decreases the appetitive behaviour for sweet and fat stimuli but not for vegetables. The reasons for this change in appetitive behaviour after the surgery remain unknown. They may be triggered by changes in gut hormones, conditioned taste aversion (negative post-ingestive effects) or changes in serum bile acids levels. This study aims to assess whether RGYB-induced gut hormone changes contribute to the decrease in appetitive behaviour for sweet and fatty foods observed after the surgery. This is a double blind controlled study comparing the effect of blocking gut hormones with somatostatin analogue (octreotide) on the appetitive behaviour for sweet-fat candies will be carried out. Appetitive behaviour will be measured using the progressive ratio task. The investigators hypothesize that blocking the gut hormones in obese patients with RYGB will increase their appetitive behaviour for sweet-fat candies.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
HEALTH_SERVICES_RESEARCH
Masking
DOUBLE
Enrollment
30
University College Dublin Clinical Research Centre
Dublin, Ireland
Progressive ratio breakpoint
In the Progressive ratio task, the participants click a computer mouse in order to obtain a sweet/fat food reward. The effort required to obtain a reward is progressively increased. The breakpoint refers to the point at which the reward value of the food stimulus is lower than the effort necessary to obtain it and the participant stops pressing the button.
Time frame: One hour
Subjective ratings
Hunger, fullness, desire in eating and nausea state will be assessed using Visual Analogue Scales (VAS).
Time frame: One hour
Gut hormones level
GLP-1, ghrelin, leptin and insulin levels will be measured.
Time frame: One hour
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