Effects of posture on gastric emptying and satiety ratings after a nutritive liquid and solid meal

To study the effects of posture and meal structure on gastric emptying and satiety, nine women ingested tomato soup and then immediately or 20 min lat er an egg sandwich, when seated and when supine. The lag time was not diffe rent, but the half-emptying time of the sandwich was 32% longer (P< 0.01) a nd the emptying rate after the lag phase was 39% slower (P< 0.01) when the subjects were supine than when they were seated. The half-emptying time of the soup was 50% longer (P< 0.01) when the subjects were supine and ingeste d the soup immediately before the sandwich than in the other three conditio ns. Postprandial hunger ratings recovered more slowly (P< 0.01) when the su bjects ingested the soup 20 min before the sandwich than when they ingested the soup immediately before the sandwich. These results suggest that postu re did not affect the intragastric distribution of the sandwich but affecte d propulsion of the meal into the intestine and that postprandial satiety w as enhanced by the cumulative effect over time of a 20-min "head start" in stimulation of intestinal receptors by emptying of the soup.