The pre meal priming of gastrointestinal satiety factors

Background. Although experimental studies on meal frequency are few, results show that increasing the number of daily meals leads to decreased energy intake (EI). No studies have yet looked at the type of meal patterning that would maximize this reduction. Objective. The purpose of this study was to determine if structured preloads affects EI, appetite, and Peptide YY (PYY) and Glucagon like peptide-1 (GLP-1) concentrations in normal weight men. Design. Eight normal weight men (25.3 +/- 2.6 kg/m 2) participated in a randomized crossover trial. In condition 1 the subjects were able to self select their snacks ad libitum. In condition 2 the subjects consumed a standardized preload (300 Kcal: 40% protein, 40% carbohydrate and 20% fat) 15 minutes prior to lunch and dinner. During condition 3, participants consumed the preload, at times that maximized their pre meal fullness levels. During each condition, a standardized breakfast was served, while lunch and dinner were self-selected from a 5 item menu, and eaten ad libitum. Daily EI, fasting and postprandial appetite, PYY, and GLP-1 were sampled every 30 minutes for 9 hours for all 3 conditions. Results. No difference in daily EI, AUC GLP-1, and PYY was noted between conditions. Desire, hunger, and PFC were found to be lowest during the control session (P<0.05). Finally, GLP-1 concentrations were correlated to fullness levels with significance during conditions 1 (R=0.81, P<0.05) and 3 (R=0.89, P<0.01). Conclusion. Structured snacking does not affect EI over the short term. Key words. Energy intake, appetite, PYY, GLP-1, preload, meal frequency