Abstract
Background/Objectives: Data on the effects of low- versus high-glycemic index (GI) meals across various carbohydrate contents on postprandial subjective satiety and gut hormones are unclear. Methods: This study aimed to investigate the effects of low-carbohydrate (45%E) or high-carbohydrate (65%E) breakfasts with low-GI (≤55) versus high-GI (>70) values on postprandial subjective satiety and plasma gut hormone concentrations in healthy adults, and whether sex and the quantity and quality of habitual dietary carbohydrate intake influenced these effects. In this exploratory secondary analysis of an acute randomized crossover controlled-feeding trial, 15 healthy adults (19–25y) were randomly assigned to one of four breakfasts on separate days: high-carbohydrate low-GI, low-carbohydrate low-GI (LCLGI), high-carbohydrate high-GI, and low-carbohydrate high-GI meals. Postprandial subjective satiety scores were measured over 240 min following breakfasts, and area under the curve (AUC240) of fullness, hunger, desire to eat, and prospective eating scores were calculated. Plasma concentrations of ghrelin, glucagon-like peptide-1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) were measured at fasting and 240 min after breakfast. Results: Both low-GI breakfasts resulted in lower AUC240 (PGI = 0.0423) of fullness and higher AUC240 (PGI = 0.0291) compared to high-GI breakfasts. The LCLGI breakfast resulted in the highest AUC240 of hunger (PInteraction = 0.0178) and prospective eating scores (PInteraction = 0.0153) compared to the other three breakfasts. The postprandial plasma concentrations of ghrelin, GLP-1, and GIP were similar among the four breakfasts (all p > 0.05). Conclusions: These findings suggested a relatively unfavorable effect of the LCLGI breakfast on postprandial satiety, without influencing postprandial ghrelin, GLP-1, or GIP concentrations.