Metabolic and cognitive coefficients in the development of hunger sensations after pure macronutrient ingestion in the morning

The effect of pure carbohydrate, protein and fat ingestion on different aspects of short-term satiety and their relation to metabolic and cognitive performance indices were studied in 15 healthy male students. Subjects were tested in three sessions for short-term changes in blood indices, indirect calorimetry, different aspects of hunger sensations as well as mood and objective cognitive performance using a repeated-measures, counterbalanced cross-over design. Measurements were made after an overnight fast before and hourly during 3 h after macronutrient ingestion. Preloads were isoenergetic (1670 kJ) spoonable creams with similar sensory properties of either pure carbohydrates, protein or fat. Overall ‘desire to eat’ and ‘gastric emptiness’ represented principal components for overall ‘hunger’ ratings, which were larger after fat and carbohydrate compared with protein ingestion. In the first hour, the hunger suppression of carbohydrates was similar to that of protein and related to changes in β-hydroxybutyrate and insulin concentrations accompanied with a preference for carbohydrate-rich food. In the third hour, it was similar to the low satiating power of fat and related to diet-induced thermogenesis together with a preference for protein-rich food. For all macronutrients feelings of ‘energy’ were negatively related to hunger sensations, whereas objective cognitive performance was positively related. Our findings suggest that the subjective satiating effect of carbohydrates seems to change with time in relation to postprandial metabolic changes, presumably mainly dependent on the glycemic response and diet-induced thermogenesis.