GLP1R and type 2 diabetes mellitus: The most critical considerations are a larger cohort of participants with T2D treated with metformin monotherapy; a longer duration of intervention; the inclusion of a companion prebiotic or additional butyrate-producing taxa; the direct measurement of GLP-1; and the collection of additional blood plasma specimens, especially during the oral meal tolerance tests to allow for identification of transient phenomena that manifest only during the postprandial period.