The goal of this study was to determine whether the type of fat plays a role in the glucose response to a meal, independent of the carbohydrate content. Ten gestational diabetic women (gestational weeks 29-34) who were well controlled on diet alone were randomized as to the order in which they would eat a meal, after overnight fast, containing saturated fat (SF) or monounsaturated fat (MUFA). Blood was drawn at 0, 60, 120, and 180 min for plasma glucose, insulin, lipid profile (triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol) and free fatty acids. After 2 weeks, each patient received the other type of meal. The test meal was composed of 20% of the total daily caloric needs based on ideal body weight. The area under the curve showed a significantly lower glucose concentration for SF meal (p = 0.001). Serum insulin concentrations followed the glucose response with the peak at the 60-min time point and a significantly lower concentration at the 180-min time point in the SF than in the MUFA group. The present study demonstrated that the addition of SF to the meal resulted in lower postprandial glucose and insulin than when the meal contained MUFA. Thus, SF may be useful in controlling postprandial glucose.