1. FEMALES 18 to 40 years of age, inclusive

2. Lean control subjects with BMI's between 19 and 25kg/m2.

3. Obese subjects with BMI's between 30 and 35kg/m2.

4. Willingness to participate in this study as evidenced by a signed, written informed consent form (ICF).

5. Willingness to avoid pregnancy and practice adequate birth control (abstinence, oral contraception, intrauterine devices, implantable devices, or barrier method with spermicide) during the time of study enrollment.

6. Negative urine pregnancy tests at all visits.

7. All subjects must be premenopausal.

8. In the follicular stage of the menstrual cycle, as determined by menstrual history at Visit 2 \&3.

9. Ambulatory outpatient (not depending exclusively on a wheelchair for mobility)

10. English is primary oral and written language.

11. Random (non fasting) Blood sugar level < 200mg/dl at screening.

12. Right-handed

1. Evidence of structural abnormality of the gastrointestinal tract or GI diseases/conditions. Exclusionary GI conditions include but are not limited to: gastrointestinal surgery (exceptions: appendectomy, benign polypectomy, cholecystectomy), pancreatitis, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), esophagitis (exception: symptom controlled reflux disease), celiac disease, gastrointestinal malignancy or obstruction, functional dyspepsia, peptic ulcer disease, lactose intolerance or any malabsorptive condition.

2. Clinical evidence of cardiovascular, respiratory, renal, hepatic, malignancy, hematologic, neurologic (including regular migraines defined as more than 1 migraine per month), psychiatric or any disease that the PI determines may interfere with safe participation in the study.

* Very specifically subjects with any history or symptoms of poor glucose control, osteoporosis, diabetes, thyroid, adrenal or other endocrine disorder.

3. Subjects with current psychiatric disorder, or history of such disorder in the past 5 years. This list includes but is not limited to bipolar disorder, alcohol or substance abuse/dependence, suicide attempt or behavior, or presence of anxiety or depression at the time of screening. Poorly controlled anxiety or depression will be determined as a result of MINI + interview by the clinician at screening.

4. Current history of chronic pain.

5. Use of investigational drugs, products or devices within 28 days prior to screen and through study participation.

6. Subjects with current use of any medications/drugs during the study that affect the central nervous system, gastrointestinal motility, autonomic activity or pain sensation, including but not limited to: opiates or other narcotic analgesics, THC, alpha adrenergic receptor antagonists, beta blockers, Ca+ blockers, prokinetics and sympatholytic agents, or antidepressants.

7. Subjects who have used diet aids within the last month.

8. Pregnancy, postpartum within 4 months or breast-feeding

9. Subjects who smoke more than 5 cigarettes per month.

10. Subjects with BMI of less than 20, between 26 and 29 and over 35.

11. Subjects with metal implants, dental retainers, large tattoos (e.g. full arm or back) or claustrophobia; making MRI safety not possible.

12. Any clinically significant abnormalities from the screening medical history or physical examination.

13. Subjects who exercise excessively (more than 8 hours a week on average).

14. Postmenopausal women and/or women who have had oophorectomies.

15. Any other condition that the investigator believes would jeopardize the safety or rights of the subject or would render the subject unable to comply with the study protocol.

16. Subject taking any medications that might interfere or react badly with the GLP-1 agonist: Exenatide

17. Subjects with a non-fasting blood glucose level at > 200 dl/ml.

18. MRI visits with fasting blood sugar < 65 or 126 mg/dl

19. Left handedness