Recruiting

Stable Isotopes

Sponsor:

University of Illinois at Urbana-Champaign

Code:

NCT07020741

Conditions

Obese Patients (BMI ≥ 30 kg/m²)

Glucose Metabolism

Protein Metabolism

Eligibility Criteria

Sex: All

Age: 19 - 59

Healthy Volunteers: Accepted

Interventions

Indispensable Amino Acid Oxidation

Stable Isotope Oral Glucose Tolerance Test

Study Details

Brief summary:

In a crossover design, 8 participants will receive caloric drinks containing stable isotopes. In one arm of the study, participants will consume 6 hourly drinks containing two stable isotopes. Repeated blood, breath, urine, and muscle biopsies will be taken. In the second arm, participants will consume 1 drink containing 75g glucose, labeled with two stable isotopes of glucose. Periodic blood and breath will be taken over three hours.

Conditions

Obese Patients (BMI ≥ 30 kg/m²)

Glucose Metabolism

Protein Metabolism

Study ID

NCT07020741

Start date

Sep 12, 2025

Status verified date

Jun, 2025

Completion date

Dec 31, 2026

Anticipated

Primary completion date

Aug 30, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 19 - 59

Healthy Volunteers: Accepted

Inclusion Criteria:

  • ages 19-59
  • Obese >/= 30 kg/m\^2 and >/= 102 cm for males and >/= 88 cm for females
  • Godin Leisure-time or exercise questionnaire <14 units

Exclusion Criteria:

1. Pregnant or become pregnant
2. Any known food allergies
3. Smoker
4. Are physically active
5. Have any known metabolic diseases
6. Have been weight unstable within the last 6 months (lost or gained >10% of body mass)
7. Non eumenorrheic or on a hormonal birth control

Study Design

Enrollment

8 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: IAAO

Participants will ingest a series of 6 hourly beverages containing 50% of the daily intake of 1.1g/kg/day

experimental: SIOGTT

Participants will consume one 75g glucose drink dissolved in 250 ml of water.

Interventions

Indispensable Amino Acid Oxidation

Participants will ingest six hourly meals designed to provide 50% of the daily intake of 1.1 g·kgLBM. Additional energy (1.5x daily resting metabolic rate), carbohydrate (55%), and fat (35%) will be provided in beverages and protein-free cookies (for palatability). The first drink will contain priming doses of NaH13CO2 (0.176 mg·kg-1), \[13C\]phenylalanine (1.86 mg·kg-1), \[2H5\]phenylalanine (0.34 mg·kg-1) with all subsequent drinks containing 1.2 mg·kg-1 \[13C\]phenylalanine and 0.51 mg·kg-1 \[2H5\]phenylalanine.

Stable Isotope Oral Glucose Tolerance Test

Participants will consume a 75g glucose drink dissolved in 250 ml of water enriched with \[6,6\_2H2\]glucose and \[13C6\]glucose.

Primary outcome measure

  • Define obesity-related whole body protein efficiency based of the IAAO method [ Time Frame: 0 - 6 hours observational period ingesting six hourly meals, within 1 week of preliminary testing. Baseline measures taken at --30 minutes. ]
  • Assessment of oral glucose tolerance based on a dual tracer technique [ Time Frame: 0- 3 hour observational period. Within 1 week of the prospective arm. Baseline taken at -30 minutes. ]

Central Contacts and Locations

Central contacts

Nicholas Burd (Associate Professor), PhD

2172440970naburd@illinois.edu

Gena L Irwin (Research Assistant), M.S

3608883281genai2@illinois.edu

Locations

Freer Hall - University of Illinois

Recruiting

Urbana, Illinois, United States, 61801

Contacts

Nicholas Burd (Associate Professor), PhD

2172440970naburd@illinois.edu

Gena L Irwin Research Assistant, M.S

3608883281genai2@illinois.edu

Principal Investigator:

Nicholas Burd, PhD

More Information

Sponsor

University of Illinois at Urbana-Champaign

Last update posted

Apr 29, 2026

Last verified

Jun, 2025

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of Illinois at Urbana-Champaign on 2026-04-29.