fMRI and Ghlrein in Obesity and Binge Eating Disorder

Binge Eating Disorder (BED) may be associated with he development of obesity. However, the pathogenesis of BED is currently unclear, thus making the development of treatment and prevention strategies for BED difficult. Differences in the mechanisms regulating food intake may go some way to reveal potential mechanisms for BED.The purpose of this study is to investigate the responses of key gut-derived hormones that are associated with the regulation of food intake and functional brain activity to food cues using fMRI in BED patients and weight matched controls.

Participants will attend the laboratory on two separate occasions following an overnight fast. Following baseline measures they will be provided wither with a 600mL (600kcal) liquid meal (Fed condition) or a volume matched amount of plain water (Fasted condition) to consume within 15 min in a randomized crossover design. Blood samples will be collected for during the subsequent 120min to measure the glucose, insulin and gut hormone responses, and subjective appetite ratings will be collected. 1500mg of acetaminophen will be added to each of the test drinks so that the appearance in the blood can be used as a proxy measure of gastric emptying. Participants will then undergo a 45min brain scan to assess the responses to visual and auditory food cues.

Blood samples, subjective appetite ratings and fMRI scan will be collected in subjects who meet the current criteria for binge eating disorder (BED) in the fed condition and fasted condition.

Blood samples, subjective appetite ratings and fMRI scan will be collected in subjects who do not meet the current criteria for BED (Controls) in the fed condition and fasted condition.

Blood Oxygen Dependent (BOLD) signal response to pictures and words of food and non-food items will be measured using functional magnetic resonance imaging (fMRI).

Blood oxygen dependent signal (BOLD) response in exposure to auditory and visual food cues will be measured during a fMRI scan and the difference between responses in the fed condition compared with those in the fasted condition.

Blood samples will be collected at -15, 0, 10, 30, 60, 90, 120 min following the ingestion of the liquid test meal and analyzed to determine the gut hormone responses.

Subjective ratings of appetite will be collected using a visual analogue scale (VAS) at -15, 0, 10, 30, 60, 90, 120 min following the liquid test meal

Inclusion Criteria: Age 18-65 years BMI 30-50 kg/m2 Weight stable (<5% change in body weight during past 3 months) Right handed Exclusion Criteria: Smokers Regular use of medications Current or intended participation in a weight-loss program (diet or exercise) Females who are pregnant or lactating