Direct Measurement of Microstructure of Ingestive Behaviour After Initiation of GLP-1 Receptor Agonist Treatment at Maximum Dose (DIGRAT)

Food intake results in the feeling of fullness, but different foods with the same energy value may induce a variable amount of fullness. Many of the satiety signals come from the lower part of the small intestine where satiety hormones are released. Obesity is associated with impaired metabolic pathways along with disordered signalling of appetite, hence individuals with obesity experience symptoms that manifest as an increase in hunger and lack of fullness. Thus, using analogues of our natural satiety/fullness hormones in individuals with obesity can suppress excessive hunger and increase fullness via slowing down gastric emptying, increasing secretion of insulin and satiety hormones and affecting on Brain-Gut axis which leads to less calorie intake and weight loss. In this study, the investigators want to review the changes in the microstructure of ingestive behaviour of participants after using the maximum dose of an obesity management medication which is similar to our natural satiety hormone via a specific device named drinkometer allowing real-time measurement of subjects' intake rate and total volume intake of one standardised liquid meal. The drinkometer device consists of an electronic scale on which a container with the liquid meal is set at each study visit in the Clinical Research Centre of St. Vincent's University Hospital. Guidance, fixed to a casing around the balance container system, delivers a tube close to the bottom of the container. The other end of the opaque tube extends to the subject and allows the sampling of the liquid meal via a mouthpiece. The tube, mouthpiece and liquid container are biocompatible and food safe. The participants will attend five visits in total including 1) Pre-Intervention site visit, 2) 4 weeks after initiation of the treatment, 3) at 12 weeks, when maximum dose is reached, 4) 26 weeks after initiation, still at maximum dose, 5) 52 weeks after initiation, still at maximum dose. The primary objective of the study is to use an analysis of ingestive behaviour to test the hypothesis that using a maximum dose of a GLP-1 receptor agonist medication changes the microstructure of the ingestive behaviour with specific patterns that can be used for behavioural phenotyping and therefore, treatment decision and prediction of the clinical outcomes.