Effects of simultaneous oral-intragastric ingestion on meal patterns and satiety in humans

Simultaneous oral-intragastric ingestion of a liquid diet was compared with oral ingestion for 15-21 days in four males or normal weight, 18-21 years old. All the subjects are significantly more (M= 222 cm3 or kcal [930 kJ] per meal, p less than .025) during simultaneous compared with oral lunches and dinners. Subjects reduced the size and frequency of breakfasts and snacks, which were always ingested orally, however, and did not gain weight. In a second experiment, the same four subjects ate significantly more (M-177 cm3 more, p less than .001 at lunch when the rate of ingestion was 200 cm3/min compared with 100 cm3/min regardless of route (oral, intragastric or simultaneous). They also ate significantly more (M=135 cm3 more, p less than 0.25) during simultaneous meals compared with oral or intragastric meals ingested at the same rate. Thus, rate of ingestion and oral stimulation are important determinants of meal size in humans.