 - Pre-Test Fast: The participant will not be able to eat or drink anything except plain, unflavored water i.e., you will fast for at least 4 hours before the mixed-meal tolerance test starts. She will get the test meal at that time. She will receive a recommendation when the visit is scheduled when to begin fasting. This recommendation is designed for no more than 10 hours of fasting, or the participants longest usual overnight fast, whichever is shorter. 