Glycemic index, cholecystokinin, satiety and disinhibition : is there an unappreciated paradox for overweight women?

Background: The clinical utility of a low glycemic index (LGI) diet for appetite and food intake control is controversial. Complicating the issue are psychological and behavioral influences related to eating. Objective: The aim of this study was to investigate the satiety and glycemic response to high Gl (HGI) and LGI meals in overweight restrained (R, n=12) and unrestrained (UR, n=10) women. Design and measurements: In a randomized crossover study, subjective satiety, cholecystokinin (CCK), glucose, insulin, triacylglyceride (TG) and free fatty acids (FFAs) were measured at defined intervals for 8 h after the participants consumed HGI or LGI test meals. Test meals were matched for energy, energy density, macronutrient content and available carbohydrate, but differed by carbohydrate source; refined grain versus whole grain, respectively. Results: The HGI meal resulted in greater satiety overall, suppressing hunger, desire to eat and prospective consumption compared with the LGI (P<0.01) meal. Plasma CCK was significantly elevated after the HGI meal compared with the LGI meal (P<0.001). Plasma glucose, insulin and TG were higher and FFAs were lower after the HGI meal compared with the LGI meal (P<0001). Dietary restraint did not significantly influence CCK (P=0.14) or subjective satiety (P>0.4); however, an interaction of restraint and disinhibition on CCK was apparent. CCK was blunted in R participants with higher disinhibition scores than UR or R participants with lower disinhibition scores (P<0.05). Conclusions: A LGI diet may not be suitable for optimal satiety and appetite control in overweight women. The relationship between cognitive influences of eating and biobehavioral outcomes requires further investigation.