Influence of breakfasts with different nutrient contents on glucose, C peptide, insulin, glucagon, triglycerides, and GIP in non-insulin-dependent diabetics.
 To examine the influence of coingestion of fat and protein in a mixed meal on carbohydrate metabolism, subjects with non-insulin-dependent diabetes mellitus (NIDDM) received three different breakfasts varying in the amount of fat and protein (group 1) or only in the amount of fat (group 2).
 Compared with the changes after a standard breakfast, insulin increased after the protein-rich meal and decreased after the fat-rich meal in group 1.
 Glucose and gastric inhibitory polypeptide (GIP) remained constant.
 In contrast, only GIP showed a significant increase after a high-fat meal in group 2.
 Thus, in NIDDM subjects, glucose and insulin responses to different mixed meals do not appear to be exclusively mediated by GIP.
 Protein was confirmed as a potent stimulator of insulin secretion.
 Other factors, such as an altered beta-cell response in diabetics to GIP or other incretions, must be considered to explain the reported results.
