The overall goal is to explore the hypothesis that prebiotic fiber Psyllium will ameliorate diarrhea in African American men (AAM) with Type2 Diabetes Mellitus (T2D).

Inclusion criteria

1. Male (M)
2. African American (AA) race
3. Age 20-70 years
4. BMI 28-59 kg/m2
5. T2D
6. A1c 6.5 - 8.9%
7. eGFR =/> 30
8. Drug-naïve or use Glipizide or newly started on Metformin (within 2 weeks).

Exclusion criteria

1. Chronic kidney disease stage 3b, 4 and 5 (eGFR < 30)
2. Insulin use
3. Oral steroids use (inhalers and creams are allowed)
4. Antibiotic use within the last month
5. Artificial heart valves
6. Hospitalization for chronic condition within 6 months prior to the study
7. History, manifestations or medications of significant metabolic, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, urological, neurological, psychiatric/ psychological disorders, or social circumstances which in the opinion of the investigator would be expected to interfere with the study or increase risk to the subject.
8. Use of other antidiabetic drugs (except glipizide and metformin).
9. Acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.

Additional Exclusion criteria for subjects who previously used Metformin:

1. Previous severe allergic reaction to metformin hydrochloride, such as angioedema.
2. Previous Metformin intolerance causing significant diarrhea or GI-upset. Would not exclude participants who had history of mild diarrhea with metformin use.
3. Previous side effects that the subject feels were related to Metformin and the subject is not interested to re-try metformin.