Effect of Ghrelin on Decision-Making

Effect of Ghrelin on Nutritional and Financial Decision-Making

This study evaluates the effect of the "hunger hormone" ghrelin on human decision-making. Participants will be given an injection of ghrelin or saline on different study days and will then be asked to make a series of computer-based decisions. The investigators hypothesize that ghrelin will increase participant's preference for energy-dense foods and will also increase impulsiveness in decision making.

Ghrelin is a hormone made by the stomach that stimulates hunger and feeding behavior. How ghrelin affects human decision-making is poorly understood. This study will investigate the effect of ghrelin on nutrition-related and time-based decisions in humans. Participants eye movements will be tracked by a computer during the decision-making process.

Inclusion Criteria:

• Ability to speak and understand English
• BMI of 18.0 - 24.9 kg/m2 or 30.0 - 50.0 kg/m2

Exclusion Criteria:

• Diagnosis of diabetes mellitus (including gestational diabetes)
• Active infections
• History of malignant or inflammatory conditions, such as rheumatoid arthritis and inflammatory bowel disease
• History of myocardial infarction or congestive heart failure
• Active liver or kidney disease
• Uncontrolled hypertension
• Pituitary or adrenal disorders or neuroendocrine tumors
• History of anorexia nervosa, bulimia, or eating disorders not otherwise specified (NOS); Score of "at risk" on the EAT-26 eating disorder screening tool
• Diagnosis of attention-deficient/hyperactivity disorder (ADHD)
• Malabsorptive gastrointestinal disease, gastroparesis, or history of gastrointestinal surgery
• Pregnancy or lactation
• Requirement of daily medications that alter gastrointestinal function (including, but not limited to, glucocorticoids, psychotropics, narcotics, and metoclopramide).
• Requirement of glasses for impaired vision (including reading glasses). Subjects who wear contact lenses for vision correction will not be excluded.
• Insufficient visual acuity to read and interpret the decision stimuli
• Insufficient motor capabilities to press a button, move the joystick, or move their eyes to indicate a response