In summary, compared to diets containing less or no red meat, diets containing red meat did not impact glycemic and insulinemic risk factors for T2D, including fasting glucose, fasting insulin, insulin sensitivity, HbA1c, pancreatic beta-cell function, and GLP-1, but did reduce postprandial glycemia in a small number of studies. Here, GCG is linked to type 2 diabetes mellitus.