Inclusion Criteria:
* Female
* 20 ≤ BMI ≤ 25
* Right handed
* Stable body weight for at least 3 consecutive months at start of study and no history of behavioral, therapeutic or surgical treatment aiming at or leading to weight loss/gain
* Subject understands the study procedures and agrees to participate in the study by giving written informed consent
Exclusion Criteria:
* Medical (current or history):
* Abdominal/thoracic surgery except appendectomy
* Gastrointestinal, endocrine (especially diabetes), or neurological diseases
* Cardiovascular, respiratory, renal or urinary diseases
* Hypertension
* Food or drug allergies
* Head trauma with loss of consciousness
* Psychiatric disorders (current or history):
* Eating disorders
* Psychotic disorders
* Major depressive disorder
* Somatoform disorder
* Emotional and/or restraint eating
* Treatment in the last 6 months with antidepressants (as MAO inhibitors), neuroleptics, sedative hypnotics, psychostimulants, glucocorticoids, appetite suppressants, estrogens, opiate, or dopamine medications. Oral contraception is allowed
* History of cannabis use or any other drug of abuse for at least 12 months prior to the study
* Intolerance of lactose
* Vegetarians
* Smoking and alcohol intake greater than 5 alcoholic units per week (one alcoholic unit = 10 gr ethanol)
* More than moderate exercise (\> 30 min, five times per week of walking or equivalent)
* High caffeine intake (\> 500 ml coffee daily or equivalent)
* Exposure to a significant amount (\> 1mSv) of ionizing radiation in other research studies within the last 12 months
* Claustrophobia or too much uneasiness in limited spaces (in order tolerate confinement during PET scanning procedures)
* Inability or unwillingness to perform all of the study procedures, or if the subject is considered unsuitable in any way by the principal investigator
* Recent participation (\< 30 days) or simultaneous participation in another clinical trial
* Any condition that would interfere with Magnetic Resonance Imaging (MRI) or PET studies (e.g., cochlear implant, metal fragments in eyes, cardiac pacemaker, neural stimulator, and metallic body inclusion or other metal implanted in the body which may interfere with MRI scanning)
* Anemia
* Pregnancy
