No Apparent Impact of Meal Glycemic Index on Postprandial Lipid Response in Lean and Abdominally Obese Women

Abstract

The objective of this study was to investigate effects of a low and high glycemic index (GI) meal and abdominal obesity on postprandial lipid response. Twenty-six obese and 15 lean women consumed a high (66) or low GI (44) meal of similar macronutrient and energy composition and then returned one to two weeks later to consume the other meal. Blood samples (0, 1, 3, 5 hour) were analyzed for insulin; free fatty acids; and total-, and chylomicron (CM)- triglycerides. Both groups (obese and lean, respectively) had significantly (p<0.05) greater insulin AUCs after consuming the high GI meal (1264 ± 889 vs. 653 ± 431 pmol/L) than the low GI meal (764 ± 708 vs. 320 ± 243). Meal type had no effect on the AUC for total-, or CM-triglyceride. Obese subjects had higher postprandial insulin (p<0.05), free fatty acid ((p<0.05), total- (p=0.06) and CM-triglycerides (p<0.05). QUICKI, an index of insulin sensitivity, was used to compare subjects from the upper and lower quartiles. Subjects with a QUICKI  0.31 (n=10) had higher AUCs for insulin (3-fold) and triglyceride (2.5-fold); and TG/HDL-C (3-fold) than subjects with a QUICKI ≥ 0.35 (n=9). These later subjects had a slightly reduced triglyceride AUC after the high GI meal (p=0.12). Women with abdominal obesity and insulin resistance have greater postprandial triglyceride response. The high GI meal increased the postprandial insulin response but appeared to have no effect on postprandial lipids. In this study, single meal GI had no effect on postprandial lipids but more research is needed, both short- and long-term studies.