Sex differences in acute energy intake regulation.

The purpose of this investigation was to determine if energy intake compensation is more accurate in males compared to females matched for age, habitual physical activity, cardiorespiratory fitness, and dietary cognitive restraint. Healthy, nonobese young men (n=12) and women (n=12) were provided with an ad libitum lunch meal on two occasions. Thirty minutes prior to the lunch meals, subjects were given either a yogurt preload (YP; 500 mL, 1988 kJ, men; 375 mL, 1507 kJ, women) or no preload (NP). Energy intake at the two lunch meals was measured. Visual analog scales were used to assess changes in hunger and fullness. Blood glucose concentrations were also determined. Energy intake compensation for the YP was significantly more accurate in the male compared to the female subjects (86.2+/-5.0 vs. 73.6+/-4.8% compensation). There were no sex differences in perceptions of hunger and satiety. In the pooled sample, hunger ratings were significantly higher in the NP condition, but there were no significant differences in fullness ratings between test meals. In the YP condition, glycemic response to the preload and the ad libitum meal was significantly higher in males compared to females. These results suggest that under acute test meal conditions, energy intake regulation is more accurate in males. Relative inability to regulate energy intake may predispose females to gain weight over time.