Clinical Trials

Group 1: Obese + Impaired Fasting Glucose (Obese + IFG)

Inclusion Criteria:

• Age 25–70 years, inclusive.

• BMI ≥28.0 and <40.0 kg/m².

• Fasting plasma glucose ≥100 and <126 mg/dL, consistent with impaired fasting glucose (IFG).

• HbA1c <6.5%.

• No current use of glucose-lowering medications.

• Willing and able to comply with all study procedures.

• Residence within a 100-mile radius of Mayo Clinic, Rochester, Minnesota.

• Eligible for age and sex matching with participants in the comparison groups, as applicable.

Exclusion Criteria:

• Age <25 or >70 years.

• BMI <28.0 or ≥40.0 kg/m².

• Fasting plasma glucose <100 or ≥126 mg/dL.

• HbA1c ≥6.5%.

• Current use of any glucose-lowering medication.

• Pregnancy or a positive pregnancy test at enrollment, if female.

• History of major upper abdominal surgery that could affect gastrointestinal or pancreatic physiology, including adjustable gastric banding, pyloroplasty, or vagotomy.

• Active systemic illness or malignancy that, in the investigator's judgment, could interfere with study participation or study outcomes.

• Symptomatic macrovascular or microvascular disease that, in the investigator's judgment, could interfere with study participation or study outcomes.

Group 2: Lean Control (Lean)

Inclusion Criteria:

• Age 25–70 years, inclusive.

• BMI ≥19.0 and <25.0 kg/m².

• Fasting plasma glucose <100 mg/dL.

• HbA1c <5.8%.

• No current use of glucose-lowering medications.

• Willing and able to comply with all study procedures.

• Residence within a 100-mile radius of Mayo Clinic, Rochester, Minnesota.

• Age- and sex-matched, as applicable, to participants in the Obese + IFG group.

Exclusion Criteria:

• Age <25 or >70 years.

• BMI <19.0 or ≥25.0 kg/m².

• Fasting plasma glucose ≥100 mg/dL.

• HbA1c ≥5.8%.

• Current use of any glucose-lowering medication.

• Pregnancy or a positive pregnancy test at enrollment, if female.

• History of major upper abdominal surgery that could affect gastrointestinal or pancreatic physiology, including adjustable gastric banding, pyloroplasty, or vagotomy.

• Active systemic illness or malignancy that, in the investigator's judgment, could interfere with study participation or study outcomes.

• Symptomatic macrovascular or microvascular disease that, in the investigator's judgment, could interfere with study participation or study outcomes.

Group 3: Type 1 Diabetes Mellitus (T1DM)

Inclusion Criteria:

• Age 25–70 years, inclusive.

• BMI ≥28.0 and <40.0 kg/m².

• Established diagnosis of type 1 diabetes mellitus (T1DM).

• HbA1c ≥5.8% and ≤9.0%.

• Current treatment with insulin.

• Willing and able to comply with all study procedures.

• Residence within a 100-mile radius of Mayo Clinic, Rochester, Minnesota.

• Age-, sex-, and BMI-matched, as applicable, to participants in the Obese + IFG group.

Exclusion Criteria:

• Age <25 or >70 years.

• BMI <28.0 or ≥40.0 kg/m².

• HbA1c <5.8% or >9.0%.

• Use of glucose-lowering medications other than insulin.

• Pregnancy or a positive pregnancy test at enrollment, if female.

• History of major upper abdominal surgery that could affect gastrointestinal or pancreatic physiology, including adjustable gastric banding, pyloroplasty, or vagotomy.

• Active systemic illness or malignancy that, in the investigator's judgment, could interfere with study participation or study outcomes.

• Symptomatic macrovascular or microvascular disease that, in the investigator's judgment, could interfere with study participation or study outcomes.

Group 4: Obese + Normal Fasting Glucose (Obese + NFG)

Inclusion Criteria:

1. Age 25–70 years, inclusive.

2. BMI ≥28.0 and <40.0 kg/m².

3. Fasting plasma glucose <100 mg/dL, consistent with normal fasting glucose (NFG).

4. HbA1c <5.8%.

5. No current use of glucose-lowering medications.

6. Willing and able to comply with all study procedures.

7. Residence within a 100-mile radius of Mayo Clinic, Rochester, Minnesota.

8. Age- and sex-matched, as applicable, to participants in the Obese + IFG group.

Exclusion Criteria:

• Age <25 or >70 years.

• BMI <28.0 or ≥40.0 kg/m².

• Fasting plasma glucose ≥100 mg/dL.

• HbA1c ≥5.8%.

• Current use of any glucose-lowering medication.

• Pregnancy or a positive pregnancy test at enrollment, if female.

• History of major upper abdominal surgery that could affect gastrointestinal or pancreatic physiology, including adjustable gastric banding, pyloroplasty, or vagotomy.

• Active systemic illness or malignancy that, in the investigator's judgment, could interfere with study participation or study outcomes.

• Symptomatic macrovascular or microvascular disease that, in the investigator's judgment, could interfere with study participation or study outcomes.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 08/10/2026. Questions regarding updates should be directed to the study team contact.