Comparing two sizes of liquid meal tests in healthy adults
Compares fixed and body-adjusted liquid meals to see how blood sugar responds in healthy adults.
Plain-language title generated from the registry record
Registry title: Variability In Mixed Meal Tests: Fixed Versus Adjusted to Energy Needs Caloric Dose
Key facts
- Where
- Phoenix, United StatesSee the site
Could this be for you?
Answer for yourself. This is not a decision: only the study team can say whether you can take part.
- Are you between 18 and 99 years old?
Source: NCT06223555, who can take part
Where in United States
- NIDDK, PhoenixPhoenix, United StatesTaking people
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Trial code
- NCT06223555
- Record updated
- 21 September 2026
- Original description
Background:Read full original descriptionShow less
Variability In Mixed Meal Tests: Fixed Versus Adjusted to Energy Needs Caloric Dose
Background:
Researchers use mixed meal tolerance tests (MMTTs) to look at how people s bodies respond to eating a meal. However, researchers do not agree on how to decide the number of calories to give in each meal. Some use fixed meals, which are the same size for everyone, and some use adjusted meals, based on the size of the person s body. Researchers want to know which MMTT is best to use for future research.
Objective:
To learn how fixed vs adjusted meals affect blood glucose levels in healthy people.
Eligibility:
Healthy people aged 18 years or older.
Design:
Participants will have 3 or 4 clinic visits of up to 8 hours in 8 weeks.
Participants will have baseline tests:
Their height, weight, and waist size will be measured.
They will have an oral glucose tolerance test: A needle attached to a tube (IV) will be inserted into a vein in the arm. They will have a sugary drink. Blood samples will be taken from the tube at intervals up to 3 hours after the drink.
They will have a body scan.
Participants will have 2 MMTT visits. One will include a fixed meal and one will include an adjusted meal. They will have tests at both visits:
Resting metabolic rate: A clear hood will be placed over the participant s head while they rest for 20 minutes. This will measure the oxygen they breathe in and out.
MMTT. Participants will have 5 minutes to drink a liquid meal. Blood samples will be taken at intervals for the next 4 hours....
Exclusion: Current use of medications, dietary supplements, or alternative therapies known to alter energy metabolism; Participants who report taking large doses of acetaminophen (> 3 grams daily) who cannot stop acetaminophen 24 hours prior to and following the meal tests will be excluded from the study; Type I or Type II Diabetes Mellitus by self-report; History or self-report of gastrointestinal disease, including inflammatory bowel diseases (e.g. Chron s disease and ulcerative colitis), malabsorption syndromes (e.g. celiac disease), gastric ulcer (active) which may alter metabolism or absorption of study food by self-report; Inability to consume provided food based on a food allergy or intolerance; Conditions not specifically mentioned above may serve as criteria for exclusion at the discretion of the investigators; Any disorder, unwillingness, or inability not covered by any other exclusion criteria which, in the investigator s and/or team s opinion, jeopardizes the safety of the participant or others or would interfere with adherence to the protocol (such as claustrophobia); Conditions not specifically mentioned above may serve as criteria for exclusion at the discretion of the investigators; Fasting plasma glucose >= 126 mg/dL; Hematologic disorders including significant anemia (male hemoglobin < 13.0 g/dL or female hemoglobin < 11.0 g/dL); An individual who meets any of the following criteria will be excluded from participation in this; study:; Current pregnancy, pregnancy within the past 6 months or currently lactating; Evidence of alcohol abuse as defined by an 8-point score on the Alcohol consumption screening AUDIT questionnaire in adults.
INCLUSION CRITERIA:; In order to be eligible to participate in this study, an individual must meet all of the following criteria:; Provision of signed and dated informed consent form; Agreement to adhere to Lifestyle Considerations throughout study duration; Males and females; Age >= 18years; Healthy, as determined by medical history, physical examination, and laboratory tests.