In healthy su bjects, following the ingestion of two meals containing potato and butter in different combinations, glucose area responses are always greater after the second meal contrary to the Staub-Traugott effect. We aimed to show the effect of added fat in the first or second meal, or both, on plasma glucose and insulin responses to ingested carbohydrate in type 2 diabetic patients.
Eight subjects with type 2 diabetes were enrolled in the study. The subjects ingested two meals consisting of potatoes containing 50 g carbohydrate, either alone or with 50 g fat in the form of butter in four different combinations on four separate days. Plasma glucose and C-peptide, serum insulin, glucagon, triglyceride, and free fatty acid concentrations were determined over an 8 hour period. The integrated area responses to the meals were quantified.
Following the first meal the glucose area responses and peak glucose concentrations were significantly lower when fat was ingested with carbohydrate. There was a delay of glucose peak time. A delay of insulin and C-peptide peak times were also documented without a decrease of peak concentrations and area responses. Addition of fat to the first or second meal caused a lower glucose area response following the second meal compared with the first.
These findings are consistent with a greater insulinogenic index which may be due to increased incretin hormone secretion consequent to fat ingestion.
Keywords: Carbohydrate, fat, ingestion, two meals, triglyceride, free fatty acids, type 2 diabetes