Inclusion Criteria:

1. Healthy as assessed by:

   • The TNO health and lifestyle questionnaire
   • Physical examination
2. Females aged 18 through 65 years on Day 01 of the study
3. Body mass index (BMI) 25 - 32 kg/m2 (if enough subjects are available, subjects with a BMI 25 - 30 kg/m2 will be included first).
4. Regular and normal Dutch eating habits (consuming mostly three main meals including breakfast) as assessed by the questionnaire on health and lifestyle
5. Non-restraint eaters, defined by a score of < 3.4 on the Dutch Eating Behaviour Questionnaire
6. Using oral contraceptives for > 3 months (only fixed phase)
7. Voluntary participation
8. Having given written informed consent
9. Willing to comply with the study procedures
10. Willing to agree to the use of all nameless data, including publication, and the confidential use and storage of all data for at least 15 years
11. Willing to agree to the disclosure of the financial benefit of participation in the study to the authorities concerned

Exclusion Criteria:

Subjects with one or more of the following characteristics will be excluded from participation:

1. Participation in any clinical trial including blood sampling and/or administration of pharmaceutical or nutritional substances up to 90 days before Day 01 of this study
2. Participation in any non-invasive clinical trial up to 30 days before Day 01 of this study, including blood sampling and/or oral, intravenous, or inhalatory administration of pharmaceutical or nutritional substances
3. Mental status that is incompatible with the proper conduct of the study (including depression)
4. Having a history of medical or surgical events that may significantly affect the study outcome, including metabolic or endocrine disease, especially diabetes type I or II; cardiovascular diseases (including hypertension); gastrointestinal diseases, including events that affect nutrient uptake or appetite; or using medication that may interfere with 5-HTP (antidepressants [selective serotonin reuptake inhibitors {SSRIs}, monoamine oxidase inhibitors {MAOIs}], migraine medication, or some hypertension medication).
5. Smoking
6. Having a history of drug abuse
7. Claustrophobia
8. Alcohol consumption > 21 units (glasses)/week
9. Not willing to stop use of supplements of minerals or vitamins from screening onwards
10. Reported food allergy or sensitivity (wheat, milk, eggs, nuts, etc.)
11. Reported unexplained weight loss or weight gain of > 2 kg in the month prior to pre-study screening
12. Practicing sports > 10 hours a week
13. Reported slimming or medically prescribed diet
14. Reported vegan, vegetarian, or macrobiotic lifestyle
15. Pregnant or lactating or wishing to become pregnant in the period of the study
16. Recent blood or plasma donation (< 1 month prior to Day 01 of the study)
17. Not willing to give up blood/plasma donation during the study
18. Personnel of TNO Quality of Life (located in Zeist), their partners and their first and second degree relatives
19. Not having a general practitioner
20. Not willing to accept information-transfer concerning participation in the study; or information regarding health, like laboratory results, findings at anamnesis or physical examination, and eventual adverse events to and from general practitioner.