The primary goal of this study was to determine the acute glycemic and endocrine responses to the reduction of fat content from a meal. On three separate occasions, 9 overweight subjects (BMI=30±1 kg/m²; 5 men, 4 women) consumed: 1) a CONTROL meal (~800 kcals; 100 g carbohydrate, 31 g fat, and 30 g protein), 2) a LOW-FAT meal (~530 kcals; 100 g carbohydrate, 1 g fat, 30 g protein), or 3) a low-fat meal + lipid infusion (LIPID INFUSION; same meal as LOW-FAT but total energy provided was same as CONTROL (800 kcal), with "missing" fat [~30 g] provided via an intravenous lipid infusion). All three meals contained ¹³C-glucose (3mg/kg body weight) in order to assess the bioavailability of ingested glucose. During the 5 h period after each meal we measured recovery of ¹³C-glucose in plasma, and plasma glucose and insulin concentrations. We also measured plasma concentration of the gastrointestinal peptides: glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and peptide YY_3-36 (PYY_3-36). Recovery of ingested ¹³C-glucose in the hour after ingestion was greater (P<0.05) during LOW-FAT than CONTROL (AUC: 1206±252 and 687±161 µM^.h, respectively). However, removing dietary fat from the meal did not affect the plasma concentration of glucose or insulin. Importantly, ¹³C-glucose recovery was not different during LOW-FAT and LIPID INFUSION (AUC: 1206±252 and 1134±247 µM^.h, respectively) indicating that the accelerated delivery of exogenous glucose found after removing fat from the meal is due exclusively to the reduction of fat in the gastrointestinal tract. In parallel with these findings, the reduction in fat calories from the meal reduced plasma concentration of GIP, GLP-1, and PYY_3-36. In summary, these data suggest that removing fat from the diet expedited exogenous glucose delivery into the systemic circulation, reduced the concentration of key gastrointestinal peptides, yet maintained plasma glucose concentration at CONTROL levels.