Effects of increasing solid component size of a mixed solid/liquid meal on solid and liquid gastric emptying

This study evaluated the hypothesis that an increase in the volume of the solid component of a mixed solid/nutrient liquid meal will result in more rapid emptying of the solid but slower liquid emptying. Eight normal volunteers were studied on two occasions after ingesting a meal containing 150 ml of 10% dextrose with either 100 g (small) or 400 g (large) of ground beef. Subjects ingested the solid component before the liquid. For the solid component, the lag phase was longer for the larger meal (56 vs. 31 min, P < 0.001). However, the absolute emptying rate for the proximal stomach and the postlag emptying rate of solid from the total stomach, when expressed as kilocalories per minute, were greater with the larger meal (P < 0.002). The lag phase was prolonged (P < 0.03) and the rate of emptying of liquid from the total and proximal stomach was slower (P < 0.001) in the large compared with the small meal. The total amount of energy delivered to the duodenum (from solid and liquid components) after the solid lag phase was greater for the larger meal (4.8 vs. 2.5 kcal/min, P < 0.002). These results indicate that an increase in the volume of the solid component of a mixed solid/liquid meal 1) prolongs the lag phase but accelerates the postlag emptying rate of solid and 2) retards intragastric distribution and emptying of liquid.