Effect of Ghrelin on 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