Postprandial changes of electrical activity of the stomach after different meals

The aim of the study was to investigate the response of the electrical activity of the stomach (electrogastrogram, EGG) to meals, different with respect to consistency, nutrient and caloric composition.

EGG was recorded in ten healthy volunteers for 30 min before and 45 min after a meal. All subjects received three different meals: A standard 500 kcal solid, a 500 cc isocaloric liquid diet of identical composition (55% carbohydrates, 15% protein, 30% fat) or 500 cc water. Data were analyzed off-line for postprandial changes.

Water as well as liquid diet induced a significant postprandial decrease, while solid food induced a slight initial decrease and a subsequent marked increase of the dominant frequency above the fasting level. The response to the solid meal was significantly different from both tap water and liquid diet, but there was no difference between liquid diet and water. All meals significantly increased the signal power with a more sustained effect over time for the liquid diet and water than the solid meal.

EGG changes seem to be more dependent on the consistency than the caloric and nutrient composition. Because of the dissociation between the timing of EGG changes and the known emptying kinetics, EGG changes seem to reflect other gastric functions rather than being associated with gastric emptying.